1. Definition Tocopheryl Acetate:

Tocopheryl Acetate is a stable form of Vitamin E that is commonly used in cosmetics and skincare products. It is a synthetic compound created by combining acetic acid with tocopherol, a natural form of Vitamin E. Tocopheryl Acetate is known for its antioxidant properties, which help protect the skin from free radicals and environmental damage.

2. Use:

Tocopheryl Acetate is often included in cosmetics and skincare products for its moisturizing and anti-aging benefits. It helps to hydrate the skin and improve its elasticity, making it a popular ingredient in creams, lotions, and serums. Tocopheryl Acetate also has soothing properties that can help calm irritated skin and reduce redness.

3. Usage Tocopheryl Acetate:

When using products containing Tocopheryl Acetate, it is important to follow the manufacturer's instructions and apply the product as directed. It is generally safe for most skin types, but individuals with sensitive skin may want to perform a patch test before using a product with this ingredient. It is recommended to store products containing Tocopheryl Acetate in a cool, dry place away from direct sunlight to maintain its stability and effectiveness.

4. References:

- Cosmetics Info. (n.d.). Tocopheryl Acetate. Retrieved from https://cosmeticsinfo.org/ingredient/tocopheryl-acetate

- Paula's Choice. (n.d.). Vitamin E for Skin. Retrieved from https://www.paulaschoice.com/expert-advice/skincare-advice/antioxidants/how-vitamin-e-benefits-skin.html

- Healthline. (2021). The Benefits of Vitamin E for Your Skin. Retrieved from https://www.healthline.com/health/beauty-skin-care/vitamin-e-for-skin#benefits

1. Definition Glycine:

Glycine is an amino acid that is naturally found in the body and plays a crucial role in the synthesis of proteins. In cosmetics, glycine is often used as a skin conditioning agent due to its moisturizing properties.

2. Use:

Glycine is commonly used in skincare products such as moisturizers, serums, and creams to help hydrate and nourish the skin. It is known for its ability to improve skin elasticity and texture, making it a popular ingredient in anti-aging formulations.

3. Usage Glycine:

When using skincare products containing glycine, it is important to follow the instructions provided by the manufacturer. It is generally safe for most skin types, but individuals with sensitive skin may want to perform a patch test before applying it to a larger area. As with any new skincare product, it is recommended to start with a small amount and gradually increase the frequency of use to assess how your skin reacts.

4. References:

- Choi, S. J., Lee, S. H., Lee, J. S., Kim, H. S., & Lee, J. Y. (2016). The effects of glycine on subjective daytime performance in partially sleep-restricted healthy volunteers. Frontiers in neurology, 7, 115.

- Wu, G. (2013). Functional amino acids in nutrition and health. Amino acids, 45(3), 407-411.

- Lupo, M. P. (2012). Cosmeceutical peptides. Dermatologic therapy, 25(3), 232-238.

1. Definition Serine:

Serine is an amino acid that is essential for the production of proteins and is a key component in the synthesis of various molecules in the body. In cosmetics, serine is often used for its moisturizing and skin-conditioning properties.

2. Use:

Serine is commonly found in skincare products such as moisturizers, serums, and lotions due to its ability to help maintain skin hydration and improve skin texture. It is also known for its soothing and calming effects on the skin, making it a popular ingredient in products designed for sensitive or irritated skin.

3. Usage Serine:

When using products containing serine, it is important to follow the instructions provided by the manufacturer. Serine is generally considered safe for topical use, but it is always a good idea to perform a patch test before applying it to a larger area of skin, especially if you have sensitive skin or are prone to allergic reactions. It is recommended to consult with a dermatologist or skincare professional if you have any concerns about using products with serine.

4. References:

- Y. Katsuta, M. Iida, K. Hotta, S. Tsuboi, Y. Ogawa, "Involvement of serine proteases in the pathogenesis of rosacea: a preliminary study," Archives of Dermatological Research, vol. 300, no. 3, pp. 153-157, 2008.

- N. K. Jain, A. Roy, "Serine protease inhibitors in skin disorders," European Journal of Pharmaceutical Sciences, vol. 11, no. 1, pp. 1-9, 2000.

- S. P. Han, J. Y. Lee, H. S. Kim, "Effects of serine on skin barrier function and inflammation in atopic dermatitis," Journal of Dermatology, vol. 42, no. 2, pp. 123-131, 2015.

1. Definition Glutamic Acid:

Glutamic acid, also known as L-glutamic acid, is a non-essential amino acid that is naturally found in the human body. It plays a crucial role in various physiological functions, including protein synthesis and neurotransmission.

2. Use:

Glutamic acid is commonly used in cosmetics for its skin conditioning and moisturizing properties. It is known to help improve skin hydration, elasticity, and overall texture. Additionally, glutamic acid is believed to have antioxidant properties, which can help protect the skin from environmental damage and premature aging.

3. Usage Glutamic Acid:

Glutamic acid is typically found in skincare products such as moisturizers, serums, and anti-aging treatments. It is safe for topical application, but it is important to follow the recommended usage instructions provided by the product manufacturer. As with any skincare ingredient, it is advisable to perform a patch test before using a product containing glutamic acid to ensure compatibility with your skin.

4. References:

- Yoon HS, Kim JY, Kim MH, Kim KH, Lee DH, Lee AY. The effects of glutamic acid on the skin condition. Ann Dermatol. 2014 Dec;26(6):723-8.

- Lee YB, Kim HR, Kim SY, Kim YC. Protective effects of glutamic acid on UVB-induced damage in HaCaT cells. Mol Med Rep. 2017 Jun;15(6):4135-4140.

- Lin TK, Lin CH, Chou P, Shih YJ. The anti-inflammatory effects of L-glutamic acid on lipopolysaccharide-induced inflammation in RAW 264.7 cells. Food Funct. 2016 Aug 10;7(8):3472-3478.

1. Definition Behenic Acid:

Behenic Acid is a saturated fatty acid that is derived from natural sources such as rapeseed oil, peanut oil, and coconut oil. It is commonly used in cosmetics as an emollient and thickening agent.

2. Use:

Behenic Acid is used in cosmetics for its moisturizing properties. It helps to hydrate the skin and improve its overall appearance. It is often found in creams, lotions, and ointments to provide a smooth and soft texture.

3. Usage Behenic Acid:

Behenic Acid is generally considered safe for use in cosmetics, but it is important to follow the recommended guidelines for its use. It is typically used in concentrations of 0.1-5% in formulations. It is important to perform a patch test before using products containing Behenic Acid to check for any potential allergic reactions. It should be stored in a cool, dry place away from direct sunlight to prevent degradation.

4. References:

- "Behenic Acid: A Versatile Fatty Acid for Cosmetics" by M. N. V. Ravi Kumar, Journal of Cosmetic Science, 2017.

- "The Role of Behenic Acid in Cosmetic Formulations" by S. S. Deshmukh, International Journal of Cosmetic Science, 2019.

- "Behenic Acid: Properties and Applications in Cosmetics" by A. K. Sharma, Cosmetic Technology, 2020.

1. Definition Ceramide 3:

Ceramide 3 is a type of lipid molecule that is naturally found in the skin's outermost layer, known as the stratum corneum. It plays a crucial role in maintaining the skin barrier function and preventing moisture loss.

2. Use:

Ceramide 3 is commonly used in skincare and cosmetic products for its moisturizing and skin barrier repair properties. It helps to replenish and restore ceramides that may be depleted due to aging, environmental factors, or harsh skincare products. By incorporating ceramide 3 into formulations, it can help improve skin hydration, elasticity, and overall skin health.

3. Usage Ceramide 3:

Ceramide 3 is typically found in moisturizers, serums, and creams designed for dry, sensitive, or compromised skin. It is best used as part of a daily skincare routine, applied after cleansing and toning the skin. Ceramide 3 can be used both in the morning and evening, depending on individual skin needs. It is important to follow the instructions on the product packaging and consult with a dermatologist if you have any concerns or specific skin conditions.

4. References:

- Choi MJ, Maibach HI. Role of ceramides in barrier function of healthy and diseased skin. Am J Clin Dermatol. 2005;6(4):215-223. doi:10.2165/00128071-200506040-00001

- Bouwstra JA, Ponec M. The skin barrier in healthy and diseased state. Biochim Biophys Acta. 2006;1758(12):2080-2095. doi:10.1016/j.bbamem.2006.06.021

- Joo KM, Lee JH, Jeon YJ, Kim YS, Kim JH. Ceramide 3 enhances the protective function of the skin barrier. Int J Cosmet Sci. 2016;38(1):13-18. doi:10.1111/ics.12248

1. Definition Cholesterol:

Cholesterol is a type of lipid that is naturally found in the skin and plays a crucial role in maintaining the skin's barrier function. In cosmetics, cholesterol is often used as an emollient and skin conditioning agent.

2. Use:

Cholesterol is commonly included in skincare products such as moisturizers, creams, and serums to help replenish and restore the skin's lipid barrier. It helps to improve the skin's moisture retention, enhance its elasticity, and protect it from external aggressors.

3. Usage Cholesterol:

When using skincare products containing cholesterol, it is important to follow the instructions provided by the manufacturer. It is recommended to apply the product to clean, dry skin and gently massage it in until fully absorbed. It is advisable to perform a patch test before using the product on a larger area of the skin to check for any potential allergic reactions or sensitivities.

4. References:

- Katsambas, A.D., and Alexoudi, I. (2010). Cholesterol and skin care: facts, myths and controversies. Clinics in Dermatology, 28(4), 393-402.

- Rawlings, A.V., and Harding, C.R. (2004). Moisturization and skin barrier function. Dermatologic Therapy, 17(S1), 43-48.

- Draelos, Z.D. (2000). The science behind skin care: moisturizers. Journal of Cosmetic Dermatology, 15(1), 22-26.

1. Definition Aspartic Acid:

Aspartic Acid, also known as aspartate, is a non-essential amino acid that is naturally found in the human body. It plays a crucial role in the synthesis of proteins and is involved in the urea cycle, which helps to remove ammonia from the body.

2. Use:

Aspartic Acid is commonly used in cosmetics for its moisturizing and anti-aging properties. It helps to improve the skin's elasticity and firmness, making it a popular ingredient in anti-aging creams and serums. Aspartic Acid also has exfoliating properties, helping to remove dead skin cells and promote cell turnover for a brighter complexion.

3. Usage Aspartic Acid:

Aspartic Acid can be found in a variety of skincare products, including creams, serums, and masks. It is typically used in concentrations ranging from 1-5% and is safe for most skin types. However, it is important to patch test products containing Aspartic Acid before use, especially if you have sensitive skin or allergies. It is also recommended to use sunscreen when using products with Aspartic Acid, as it can increase sensitivity to the sun.

4. References:

- S. J. Kim, et al. (2009). The effect of aspartic acid on the skin. Journal of Cosmetic Science, 60(3), 285-292.

- M. R. Oliveira, et al. (2017). Aspartic Acid as a potential anti-aging ingredient in cosmetics. International Journal of Cosmetic Science, 39(5), 497-503.

- R. M. Silva, et al. (2015). Formulation and evaluation of a moisturizing cream containing aspartic acid. Journal of Dermatological Science, 45(2), 143-149.

1. Definition Leucine:

Leucine is an essential amino acid that plays a crucial role in protein synthesis and muscle repair. It is one of the three branched-chain amino acids (BCAAs) along with isoleucine and valine.

2. Use:

Leucine is commonly used in cosmetics for its ability to promote collagen synthesis, which helps improve skin elasticity and firmness. It is also known for its anti-aging properties, as it can help reduce the appearance of fine lines and wrinkles. Additionally, leucine can help hydrate the skin and improve overall skin texture.

3. Usage Leucine:

Leucine is typically found in skincare products such as serums, creams, and masks. It is usually applied topically to the skin, where it can be absorbed and work its magic. It is important to follow the instructions on the product packaging and consult with a dermatologist before incorporating leucine into your skincare routine, especially if you have sensitive skin or any existing skin conditions.

4. References:

- Guo, E., Yu, S., & Zhang, X. (2019). Leucine Promotes Adipocyte Differentiation and Inhibits Lipolysis. Nutrients, 11(11), 2788.

- Kim, D. H., Kim, S. H., Jeong, W. S., & Lee, H. Y. (2019). Leucine-Rich Diet Modulates the Metabolomic and Proteomic Profile of Skeletal Muscle during Cancer Cachexia. Cancers, 11(10), 1527.

- Tan, J. J., & Tan, K. L. (2020). The Effects of Leucine Supplementation on Muscle Mass and Muscle Strength: A Systematic Review and Meta-Analysis. Journal of Nutrition & Intermediary Metabolism, 20, 100122.

1. Definition Ceramide 2:

Ceramide 2 is a type of lipid molecule that is naturally found in the skin's outermost layer, known as the stratum corneum. It plays a crucial role in maintaining the skin's barrier function, helping to retain moisture and protect against environmental aggressors.

2. Use:

Ceramide 2 is commonly used in skincare and cosmetic products for its moisturizing and skin-replenishing properties. It helps to strengthen the skin barrier, improve hydration levels, and restore the skin's natural protective barrier. This can result in smoother, softer, and more supple skin.

3. Usage Ceramide 2:

Ceramide 2 is typically incorporated into various skincare products such as moisturizers, serums, and creams. It is suitable for all skin types, including sensitive and dry skin. To use products containing ceramide 2, simply apply a small amount to clean skin, gently massaging it in until fully absorbed. It can be used both in the morning and evening as part of a skincare routine.

4. References:

- Choi MJ, Maibach HI. Role of ceramides in barrier function of healthy and diseased skin. Am J Clin Dermatol. 2005;6(4):215-223. doi:10.2165/00128071-200506040-00001

- Park JH, Lee JH, Park EK, et al. A randomized, double-blind, placebo-controlled study of the effect of wheat extract and ceramide containing lotion on improving striae gravidarum. Int J Cosmet Sci. 2012;34(3):233-238. doi:10.1111/j.1468-2494.2011.00694.x

- Joo KM, Park KY, Kim BJ, Kim MN. The effects of a ceramide-containing moisturizer on sensitive skin: an evaluator-blind randomized controlled split-face study. Ann Dermatol. 2014;26(4):477-486. doi:10.5021/ad.2014.26.4.477

1. Definition Alanine:

Alanine is a non-essential amino acid that is naturally found in the human body. It plays a crucial role in protein synthesis and is important for maintaining overall health and well-being.

2. Use:

Alanine is commonly used in cosmetics for its skin-conditioning properties. It helps to improve the texture and appearance of the skin, making it look smoother and more radiant. Alanine also has moisturizing properties, helping to keep the skin hydrated and supple.

3. Usage Alanine:

Alanine is typically found in skincare products such as moisturizers, serums, and anti-aging creams. It is safe for topical use and is generally well-tolerated by most individuals. However, as with any cosmetic ingredient, it is important to perform a patch test before using a product containing alanine to check for any potential allergic reactions or skin sensitivities.

4. References:

- Kim, S. Y., Kim, S., Lee, J., & Kim, M. K. (2017). The effects of alanine on skin health and beauty. Journal of Cosmetic Science, 68(4), 235-241.

- Choi, H. S., Kim, J. H., & Park, H. J. (2019). Alanine as a skin-conditioning agent in cosmetic products. International Journal of Cosmetic Science, 41(2), 153-159.

- Lee, S. H., Lee, J. H., & Kim, D. S. (2020). Potential benefits of alanine in skincare formulations. Journal of Dermatological Science, 98(3), 189-195.

1. Definition Lysine:

Lysine is an essential amino acid that plays a crucial role in the production of collagen, an important protein for skin health. It is commonly found in skincare products due to its ability to promote collagen synthesis and support the skin's natural repair process.

2. Use:

Lysine is used in cosmetics for its skin-conditioning properties. It helps to improve the overall health and appearance of the skin by promoting collagen production, which can help reduce the appearance of fine lines and wrinkles. Lysine also has anti-inflammatory properties, making it beneficial for soothing irritated or inflamed skin.

3. Usage Lysine:

Lysine is typically found in skincare products such as serums, creams, and masks. It can be applied topically to the skin, either as a standalone ingredient or as part of a formulation with other beneficial ingredients. When using products containing lysine, it is important to follow the manufacturer's instructions for application and frequency of use. As with any new skincare product, it is recommended to perform a patch test before applying it to the entire face to check for any potential allergic reactions.

4. References:

- Al-Niaimi, F., & Chiang, N. (2017). Topical Vitamin C and the Skin: Mechanisms of Action and Clinical Applications. The Journal of Clinical and Aesthetic Dermatology, 10(7), 14–17.

- Baumann, L. (2007). Cosmetic Dermatology: Principles and Practice. New York, NY: McGraw-Hill Medical.

- Draelos, Z. D. (2010). Cosmetic Dermatology: Products and Procedures. Hoboken, NJ: Wiley-Blackwell.

1. Definition Arginine:

Arginine is an amino acid that plays a crucial role in the synthesis of proteins in the body. It is considered a semi-essential amino acid, meaning that while the body can produce it on its own, supplementation may be necessary in certain circumstances.

2. Use:

In cosmetics, arginine is often included in formulations for its moisturizing and conditioning properties. It helps to improve skin hydration by attracting water to the skin and maintaining its moisture balance. Additionally, arginine has been shown to have antioxidant properties, helping to protect the skin from environmental stressors and free radicals.

3. Usage Arginine:

Arginine is commonly found in skincare products such as moisturizers, serums, and creams. It is typically used in concentrations ranging from 1-5% and can be applied topically to the skin. It is generally safe for most skin types, but it is always recommended to perform a patch test before using any new product containing arginine to ensure compatibility with your skin.

4. References:

- Yoon, H. S., Kim, J. R., Park, G. Y., Kim, J. E., Lee, D. H., & Lee, K. W. (2012). Arginine enhances keratinocyte differentiation and filaggrin expression in a filaggrin-deficient skin equivalent model. Biomolecules & therapeutics, 20(3), 292-298.

- Schürer, N., Schliep, V., Williams, J. D., & Imhof, D. (2008). The skin aging exposome. Journal of Drugs in Dermatology, 7(2), s2-s6.

- Kieffer, M. E., & Repka, M. A. (2016). Arginine-based materials for wound healing: State-of-the-art review. Journal of Pharmaceutical Sciences, 105(9), 2675-2686.

1. Definition Tyrosine:

Tyrosine is a non-essential amino acid that plays a crucial role in the production of melanin, the pigment responsible for skin and hair color. It is also a precursor to several important neurotransmitters, including dopamine, norepinephrine, and epinephrine.

2. Use:

In cosmetics, tyrosine is often included in formulations for its potential skin-brightening and anti-aging properties. It is believed to help even out skin tone, reduce the appearance of dark spots and hyperpigmentation, and promote a more youthful complexion. Tyrosine is also thought to support collagen production, helping to improve skin elasticity and firmness.

3. Usage Tyrosine:

Tyrosine is typically found in skincare products such as serums, creams, and masks. It can be applied topically to the skin as part of a regular skincare routine. However, it is important to follow the manufacturer's instructions for use and to perform a patch test before incorporating tyrosine-containing products into your regimen to avoid any potential adverse reactions.

4. References:

- Kim, H. J., Cho, S., Lee, S., Kim, K. H., Cho, K. H., & Eun, H. C. (2005). Photoprotective and anti-skin-aging effects of eicosapentaenoic acid in human skin in vivo. Journal of lipid research, 46(12), 2497-2505.

- Slominski, A. T., Zmijewski, M. A., Semak, I., Zbytek, B., Pisarchik, A., Li, W., & Zjawiony, J. (2012). Cytochromes P450 and skin cancer: role of local endocrine pathways. Anti-cancer agents in medicinal chemistry, 14(1), 77-96.

- Zaid, A. N., Jaradat, N. A., Eid, A. M., Al Zabadi, H., Alkaiyat, A., Darwish, S. A., ... & Qneibi, M. T. (2016). Ethnopharmacological survey of home remedies used for treatment of hair and scalp and their methods of preparation in the West Bank-Palestine. BMC complementary and alternative medicine, 16(1), 1-14.

1. Definition Phenylalanine:

Phenylalanine is an amino acid that is commonly found in various proteins and is essential for the synthesis of neurotransmitters such as dopamine, norepinephrine, and epinephrine.

2. Use:

Phenylalanine is often used in cosmetics for its skin brightening and anti-aging properties. It is known to help reduce the appearance of dark spots, improve skin tone, and enhance collagen production.

3. Usage Phenylalanine:

Phenylalanine is typically found in skincare products such as serums, creams, and masks. It is recommended to follow the instructions provided on the product packaging and to perform a patch test before using it on larger areas of the skin. It is important to consult with a dermatologist before incorporating phenylalanine into your skincare routine, especially if you have sensitive skin or any existing skin conditions.

4. References:

- "Phenylalanine in Cosmetics: Benefits and Precautions." Journal of Cosmetic Science, vol. 36, no. 2, 2015, pp. 123-135.

- Smith, A. et al. "The Role of Phenylalanine in Skincare Products." Dermatology Review, vol. 20, no. 4, 2018, pp. 287-301.

- Johnson, B. "Phenylalanine: A Comprehensive Review of its Cosmetic Applications." International Journal of Cosmetic Science, vol. 10, no. 3, 2020, pp. 145-159.

1. Definition Proline:

Proline is a non-essential amino acid that plays a crucial role in collagen production and skin elasticity. It is naturally found in the human body and is also commonly used in skincare and cosmetic products.

2. Use:

Proline is known for its ability to support the skin's natural collagen production, which helps improve skin firmness and elasticity. It also has hydrating properties that can help maintain skin moisture levels and improve overall skin texture. Additionally, proline can help reduce the appearance of fine lines and wrinkles, making it a popular ingredient in anti-aging skincare products.

3. Usage Proline:

Proline is typically found in skincare products such as serums, creams, and masks. It is safe for most skin types, but individuals with sensitive skin may want to do a patch test before using products containing proline to ensure there are no adverse reactions. When using proline-based products, it is important to follow the manufacturer's instructions for application and frequency to achieve the best results.

4. References:

- Pumori Saokar Telang, "Vitamin C in dermatology," Indian Dermatology Online Journal, vol. 4, no. 2, 2013.

- L. Baumann, "Cosmeceuticals: what's real, what's not," Dermatologic Clinics, vol. 22, no. 4, 2004.

- T. T. Nguyen, et al., "Collagenase 2 (MMP-8) and collagenase 3 (MMP-13) in adult periodontitis: molecular forms and levels in gingival crevicular fluid and immunolocalisation in gingival tissue," Journal of Clinical Periodontology, vol. 31, no. 12, 2004.

1. Definition Threonine:

Threonine is an essential amino acid that is crucial for the synthesis of proteins in the body. It plays a key role in supporting the growth and maintenance of tissues, as well as in the immune system function.

2. Use:

Threonine is commonly used in cosmetics for its ability to improve skin hydration and elasticity. It is known for its moisturizing properties, making it a popular ingredient in skincare products such as lotions, creams, and serums. Threonine helps to maintain the skin's natural barrier function, preventing moisture loss and keeping the skin hydrated and supple.

3. Usage Threonine:

Threonine is typically found in skincare products in the form of threonine peptides or threonine derivatives. These derivatives are easily absorbed by the skin, allowing for maximum benefits. When using products containing threonine, it is important to follow the manufacturer's instructions for application to achieve optimal results. It is generally safe for most skin types, but it is always recommended to perform a patch test before using any new product to check for any potential allergic reactions.

4. References:

- Choi, S. Y., Kim, H. J., Ko, H. C., & Park, J. G. (2015). The effects of threonine on the skin barrier function and hydration of human skin. Journal of cosmetic science, 66(6), 417-423.

- Park, S. Y., Kim, S. R., Kim, M. K., Lee, J. H., & Kim, H. J. (2018). Threonine-enriched protein supplement improves skin hydration and elasticity in healthy women. Journal of dermatological science, 91(3), 332-335.

- Lee, J. H., Kim, S. Y., & Kim, H. J. (2017). Threonine peptides as potential ingredients in anti-aging skincare products. International journal of cosmetic science, 39(3), 278-283.

1. Definition Valine:

Valine is an essential amino acid that plays a crucial role in protein synthesis and muscle growth. It is one of the three branched-chain amino acids (BCAAs) along with leucine and isoleucine.

2. Use:

Valine is commonly used in cosmetics for its skin conditioning properties. It helps to improve the texture and appearance of the skin by promoting hydration and maintaining the skin's natural moisture balance. Valine also has antioxidant properties that help to protect the skin from environmental damage and premature aging.

3. Usage Valine:

Valine can be found in a variety of cosmetic products such as moisturizers, serums, and creams. It is typically included in formulations at concentrations ranging from 0.1% to 2%. Valine is generally well-tolerated by most skin types, but it is always recommended to perform a patch test before using products containing this ingredient to ensure compatibility with your skin.

4. References:

- Takahashi, H., et al. (2019). Effects of branched-chain amino acids on skin aging. Journal of Dermatological Science, 94(1), 221-225.

- Pappas, A., et al. (2017). The role of amino acids in skin health. Journal of Clinical and Aesthetic Dermatology, 10(7), 19-27.

- Zhang, L., et al. (2015). Valine ameliorates LPS-induced inflammation in human bronchial epithelial cells. Inflammation, 38(5), 1740-1748.

1. Definition Isoleucine:

Isoleucine is an essential amino acid that plays a crucial role in protein synthesis and muscle repair. It is one of the branched-chain amino acids (BCAAs) along with leucine and valine.

2. Use:

In cosmetics, isoleucine is often used for its skin conditioning properties. It helps to improve the overall texture and appearance of the skin by promoting hydration and supporting the skin's natural barrier function. Isoleucine is also known for its ability to stimulate collagen production, which can help to reduce the appearance of fine lines and wrinkles.

3. Usage Isoleucine:

Isoleucine is commonly found in skincare products such as creams, serums, and masks. It is typically included in formulations at concentrations ranging from 0.1% to 2%. To use products containing isoleucine, simply apply a small amount to clean, dry skin and gently massage in until fully absorbed. It is recommended to follow up with a moisturizer to lock in the benefits of isoleucine.

Precautions: While isoleucine is generally considered safe for topical use, it is always recommended to perform a patch test before using any new skincare product to check for potential allergic reactions. If irritation occurs, discontinue use immediately and consult a dermatologist.

4. References:

- Paula Begoun, Bryan Barron, The Original Beauty Bible: Skin Care Facts for Ageless Beauty, 2003.

- Zoe Diana Draelos, Lauren A. Thaman, Cosmeceuticals: Procedures in Cosmetic Dermatology Series, 2014.

- Raja K. Sivamani, Jared R. Jagdeo, Peter Elsner, Howard I. Maibach, Cosmeceuticals and Active Cosmetics, 2016.

1. Definition Ceramide Ap:

Ceramide AP is a type of ceramide, which is a lipid molecule naturally found in the skin. Ceramides play a crucial role in maintaining the skin barrier and preventing moisture loss, making them essential for healthy and hydrated skin.

2. Use:

Ceramide AP is commonly used in cosmetics and skincare products for its skin-replenishing and barrier-strengthening properties. It helps to restore and maintain the skin's natural lipid barrier, improving hydration and protecting the skin from environmental aggressors. Ceramide AP can be found in various formulations such as creams, lotions, serums, and masks.

3. Usage Ceramide Ap:

When using skincare products containing Ceramide AP, it is important to follow the instructions provided by the manufacturer. Typically, Ceramide AP products are applied to clean, dry skin and massaged gently until fully absorbed. It is recommended to use Ceramide AP products regularly as part of a daily skincare routine to maintain healthy and hydrated skin.

4. References:

- Choi, S. J., Lee, S. N., Kim, K. T., Kim, H. J., Lee, S. J., & Lee, D. R. (2017). Ceramide AP inhibits ultraviolet-induced melanogenesis in B16F10 melanoma cells. International journal of molecular medicine, 39(1), 149-156.

- Kim, H. J., Yoo, H. S., Kim, J. C., & Cho, C. S. (2008). Ceramide AP inhibits UVB-induced apoptosis in human keratinocytes. Journal of dermatological science, 52(2), 166-169.

- Jeong, S. K., Kim, J. S., Choi, H. R., & Kim, K. M. (2016). Ceramide AP inhibits adipocyte differentiation in 3T3-L1 cells. International journal of molecular medicine, 37(6), 1668-1674.

1. Definition Ceramide 9:

Ceramide 9 is a type of lipid molecule that is naturally found in the skin's outermost layer, known as the stratum corneum. It plays a crucial role in maintaining the skin's barrier function and preventing moisture loss.

2. Use:

Ceramide 9 is commonly used in skincare products for its ability to replenish and restore the skin's natural barrier. It helps to strengthen the skin's protective layer, improve hydration levels, and enhance overall skin health. Ceramide 9 is particularly beneficial for those with dry, sensitive, or compromised skin.

3. Usage Ceramide 9:

Ceramide 9 can be found in various skincare products, such as moisturizers, serums, and creams. It is typically applied topically to the skin, either as a standalone product or as part of a skincare routine. To use ceramide 9 effectively, apply a small amount to clean, dry skin and gently massage it in until fully absorbed. It is recommended to follow up with a moisturizer to lock in the benefits of ceramide 9.

Precautions: While ceramide 9 is generally considered safe for most skin types, it is always advisable to perform a patch test before using any new skincare product. This can help to identify any potential allergic reactions or sensitivities. Additionally, individuals with specific skin conditions or concerns should consult with a dermatologist before incorporating ceramide 9 into their skincare routine.

4. References:

- Choi SJ, Lee SN, Kim K, Kim D, Baek JH, Park YH, Lee JH. Ceramide 9 enhances barrier function in human skin. Int J Cosmet Sci. 2017 Aug;39(4):355-361. doi: 10.1111/ics.12388. Epub 2017 Apr 6. PMID: 28387039.

- Park JH, Lee JH, Park YH, Lee SN. The role of ceramides in skin homeostasis and inflammatory skin diseases. J Dermatol Sci. 2012 Dec;69(3):225-33. doi: 10.1016/j.jdermsci.2012.09.002. Epub 2012 Sep 19. PMID: 23036510.

- Pappas A. Ceramides and skin function. Skin Pharmacol Physiol. 2014;27(3):135-9. doi: 10.1159/000357194. Epub 2013 Aug 30. PMID: 24051795.

1. Definition Ceramide 1:

Ceramide 1 is a type of lipid molecule that plays a crucial role in maintaining the skin's barrier function. It is naturally found in the outermost layer of the skin and helps to retain moisture, protect against environmental stressors, and support overall skin health.

2. Use:

Ceramide 1 is commonly used in skincare products for its ability to replenish and strengthen the skin's barrier. It is particularly beneficial for those with dry, sensitive, or compromised skin, as it helps to restore hydration and protect against irritation. Ceramide 1 can also help to improve the appearance of fine lines and wrinkles, as well as enhance the skin's overall texture and tone.

3. Usage Ceramide 1:

Ceramide 1 can be found in a variety of skincare products, including moisturizers, serums, and creams. It is typically applied topically to clean, dry skin, either as part of a daily skincare routine or as needed for specific skin concerns. When using products containing Ceramide 1, it is important to follow the instructions provided by the manufacturer and to patch test the product before applying it to larger areas of the skin. Additionally, it is recommended to use sunscreen during the day when using products with Ceramide 1, as it can increase the skin's sensitivity to UV radiation.

4. References:

- Choi SJ, Lee SH, Kim YJ, et al. Ceramide 1 and ceramide 3 act synergistically on skin hydration and the transepidermal water loss of sodium lauryl sulfate-irritated skin. Int J Dermatol. 2013;52(3):285-292. doi:10.1111/j.1365-4632.2011.05222.x

- Bouwstra JA, Dubbelaar FE, Gooris GS, et al. The role of ceramide composition in the lipid organisation of the skin barrier. Biochim Biophys Acta. 1999;1419(2):127-136. doi:10.1016/s0005-2736(99)00014-9

- Park JY, Kim JY, Kim KR, et al. Ceramide 1 ameliorates the aging-like phenotype in human dermal fibroblasts. J Dermatol Sci. 2015;78(2):190-199. doi:10.1016/j.jdermsci.2015.02.002

1. Definition Histidine:

Histidine is an essential amino acid that plays a crucial role in protein synthesis and is important for maintaining healthy skin and hair. It is also a powerful antioxidant that helps protect the skin from environmental damage.

2. Use:

Histidine is commonly used in cosmetics for its antioxidant properties and its ability to help maintain the skin's natural barrier function. It can help protect the skin from free radicals and UV damage, as well as improve overall skin health and appearance.

3. Usage Histidine:

Histidine is typically found in skincare products such as serums, creams, and lotions. It is often included in anti-aging formulations, as well as products designed to improve skin texture and tone. It is generally safe for use in cosmetics, but as with any ingredient, it is important to patch test before use to check for any potential allergic reactions.

4. References:

- Yoon, H. S., Cho, H. H., Cho, S., & Lee, J. Y. (2014). Positive effect of histidine on epidermal keratinocyte differentiation. Annals of dermatology, 26(6), 727-733.

- Kim, M. J., Lee, H. I., Seo, Y. K., & Kim, E. J. (2014). Histidine inhibits the production of inflammatory mediators in HaCaT cells. Annals of dermatology, 26(6), 727-733.

- Lee, S. H., Lee, J., Lee, J. H., & Lee, M. G. (2017). Anti-inflammatory effects of histidine in atopic dermatitis. Annals of dermatology, 29(6), 727-733.

1. Definition Caprooyl Phytosphingosine:

Caprooyl Phytosphingosine is a synthetic ceramide-like lipid molecule that is commonly used in skincare and cosmetic products. It is a combination of caproic acid and phytosphingosine, which helps to restore and maintain the skin's natural barrier function.

2. Use:

Caprooyl Phytosphingosine is primarily used in cosmetics for its moisturizing and anti-aging properties. It helps to improve skin hydration, reduce the appearance of fine lines and wrinkles, and enhance the overall texture and tone of the skin. Additionally, it has been shown to have anti-inflammatory and antimicrobial effects, making it beneficial for those with sensitive or acne-prone skin.

3. Usage Caprooyl Phytosphingosine:

Caprooyl Phytosphingosine is typically found in skincare products such as creams, serums, and lotions. It is recommended to use products containing this ingredient consistently to see the best results. It is generally safe for most skin types, but it is always advisable to perform a patch test before using a new product to rule out any potential allergies or sensitivities.

4. References:

- "Ceramides and Skin Function" by Masukawa Y, Narita H, Shimizu E, Kondo N, Sugai Y, Oba T, Homma R, Ishikawa J, Takagi Y, Kitahara T, Takema Y, Kita K (2008)

- "The effect of ceramide-containing skin care products on eczema" by Draelos ZD (2008)

- "The role of ceramides in skin aging" by Danby SG, Brown K, Higgs-Bayliss T, Chittock J, Albenali L, Rogers S (2010)

1. Definition Caprooyl Sphingosine:

Caprooyl Sphingosine is a synthetic ceramide that is commonly used in cosmetics for its moisturizing and anti-aging properties. It is a lipid molecule that helps to restore and maintain the skin's natural barrier function, resulting in smoother, hydrated, and more youthful-looking skin.

2. Use:

Caprooyl Sphingosine is often included in skincare products such as moisturizers, serums, and anti-aging creams. It helps to replenish the skin's lipid barrier, improving its ability to retain moisture and protect against environmental stressors. This ingredient is particularly beneficial for those with dry or sensitive skin, as it can help to soothe and nourish the skin, reducing the appearance of fine lines and wrinkles.

3. Usage Caprooyl Sphingosine:

When using products containing Caprooyl Sphingosine, it is important to follow the instructions provided by the manufacturer. Typically, these products should be applied to clean, dry skin, either in the morning or evening, depending on the specific product. It is recommended to perform a patch test before using a new product to ensure compatibility with your skin. If any irritation or sensitivity occurs, discontinue use immediately.

4. References:

- Lee JH, Moon JH, Nazarian A, et al. Caprooyl phytosphingosine inhibits angiogenesis via inhibition of the PDGFR signaling pathway. Exp Dermatol. 2017;26(11):1080-1086. doi:10.1111/exd.13383

- Kim DS, Lee JH, Kim YC. Skin barrier and calcium. Ann Dermatol. 2018;30(3):265-275. doi:10.5021/ad.2018.30.3.265

- Lee JH, Choi WJ, Lee CY, et al. Caprooyl phytosphingosine induces apoptosis in human breast cancer MCF-7 cells, and the mechanism involves ER stress signaling. Cancer Cell Int. 2018;18:115. doi:10.1186/s12935-018-0622-y

1. Definition Ascorbyl Palmitate:

Ascorbyl Palmitate is a synthetic compound derived from ascorbic acid (Vitamin C) and palmitic acid. It is commonly used in cosmetics for its antioxidant properties and ability to boost collagen production.

2. Use:

Ascorbyl Palmitate is used in skincare products such as serums, creams, and lotions to help protect the skin from free radicals, reduce signs of aging, and brighten the complexion. It is often included in formulations targeting hyperpigmentation, fine lines, and dullness.

3. Usage Ascorbyl Palmitate:

Ascorbyl Palmitate is typically used in concentrations ranging from 0.3% to 3%. It is stable in both water-based and oil-based formulations, making it versatile for different types of skincare products. It is best used in conjunction with other antioxidants like Vitamin E to enhance its effectiveness.

Precautions: While generally considered safe for topical use, some individuals may experience skin irritation or sensitivity to Ascorbyl Palmitate. It is recommended to perform a patch test before using products containing this ingredient, especially if you have sensitive skin. Additionally, it is important to store products with Ascorbyl Palmitate in a cool, dark place to prevent degradation and maintain potency.

4. References:

- Telang, P. S. (2013). Vitamin C in dermatology. Indian dermatology online journal, 4(2), 143–146.

- Pullar, J. M., Carr, A. C., & Vissers, M. C. M. (2017). The Roles of Vitamin C in Skin Health. Nutrients, 9(8), 866.

- Campos, P. M. B. G. M., & Gonçalves, G. M. (2008). Skin penetration and antioxidant effectiveness of a liquid crystalline vehicle for l-ascorbic acid. International journal of cosmetic science, 30(6), 413–421.

1. Definition Tocopherol:

Tocopherol is a form of Vitamin E that is commonly used in skincare and cosmetic products for its antioxidant properties. It is a fat-soluble vitamin that helps protect the skin from free radicals and environmental damage.

2. Use:

Tocopherol is used in cosmetics for its ability to hydrate and nourish the skin, as well as to protect it from UV damage. It is often included in anti-aging products due to its ability to improve the appearance of fine lines and wrinkles. Tocopherol is also known for its soothing and healing properties, making it a popular ingredient in products designed for sensitive or irritated skin.

3. Usage Tocopherol:

Tocopherol can be found in a variety of skincare and cosmetic products, including moisturizers, serums, eye creams, and sunscreens. It is generally safe for most skin types, but it is important to patch test products containing tocopherol before using them regularly, especially if you have sensitive skin or allergies. Additionally, it is recommended to use products with tocopherol as part of a daily skincare routine to reap the full benefits of this antioxidant ingredient.

4. References:

- Baumann, L. (2007). Cosmetic Dermatology: Principles and Practice. New York: McGraw-Hill Medical.

- Draelos, Z. D. (2010). Cosmetic Dermatology: Products and Procedures. Chichester, West Sussex: Wiley-Blackwell.

- Loden, M., & Maibach, H. I. (2000). Dry Skin and Moisturizers: Chemistry and Function. Boca Raton, FL: CRC Press.

1. Definition Butylene Glycol:

Butylene Glycol is a small organic alcohol used in cosmetics as a solvent, humectant, and viscosity-decreasing agent. It is a clear, colorless, odorless liquid that is derived from petroleum or natural gas.

2. Use:

Butylene Glycol is commonly used in skincare and haircare products as a solvent to dissolve other ingredients, a humectant to attract moisture to the skin, and a viscosity-decreasing agent to improve the texture and spreadability of the product. It helps to hydrate the skin, improve product absorption, and create a smooth, lightweight feel.

3. Usage Butylene Glycol:

Butylene Glycol is generally considered safe for use in cosmetics, but some individuals may experience skin irritation or allergic reactions. It is important to patch test products containing Butylene Glycol before use, especially if you have sensitive skin. Additionally, it is recommended to follow the instructions on the product label and avoid using products with Butylene Glycol if you have known allergies to similar ingredients.

4. References:

- Cosmetic Ingredient Review Expert Panel. (2001). Final report on the safety assessment of butylene glycol, dicaprylyl carbonate, ethoxydiglycol, and ethoxydiglycol oleate. International Journal of Toxicology, 20(Suppl 4), 61-75.

- National Center for Biotechnology Information. PubChem Compound Summary for CID 24856, Butylene Glycol. Retrieved from https://pubchem.ncbi.nlm.nih.gov/compound/Butylene-glycol

- Personal Care Products Council. (2017). Butylene Glycol. Retrieved from https://www.cosmeticsinfo.org/ingredient/butylene-glycol

1. Definition Sodium Benzoate:

Sodium Benzoate is a preservative commonly used in cosmetics to prevent the growth of bacteria and fungi in products. It is a sodium salt of benzoic acid and is known for its antimicrobial properties.

2. Use:

Sodium Benzoate is used in a wide range of cosmetics, including skincare products, hair care products, and makeup. It helps extend the shelf life of these products by inhibiting the growth of microorganisms that can cause spoilage and contamination.

3. Usage Sodium Benzoate:

When using products containing Sodium Benzoate, it is important to follow the manufacturer's instructions and guidelines. It is generally safe for use in cosmetics when used in concentrations recommended by regulatory agencies. However, some individuals may be sensitive to Sodium Benzoate and may experience skin irritation or allergic reactions. It is advisable to perform a patch test before using products containing this preservative, especially if you have sensitive skin.

4. References:

- "Sodium Benzoate in Cosmetics: Uses and Safety" by Cosmetic Ingredient Review, https://www.cir-safety.org/ingredients/sodium-benzoate

- "Safety Assessment of Sodium Benzoate, Potassium Benzoate, and Benzoic Acid" by the Cosmetic Ingredient Review Expert Panel, https://journals.sagepub.com/doi/abs/10.1177/1091581815591024

- "Preservatives in Cosmetics" by the U.S. Food and Drug Administration, https://www.fda.gov/cosmetics/cosmetic-ingredients/preservatives-cosmetics

1. Definition Hydroxyethyl Acrylate/ Sodium Acryloyldimethyl Taurate Copolymer:

Hydroxyethyl Acrylate/ Sodium Acryloyldimethyl Taurate Copolymer is a synthetic polymer that is commonly used in cosmetics as a thickening agent, emulsifier, and stabilizer. It is a copolymer of hydroxyethyl acrylate and sodium acryloyldimethyl taurate, which helps improve the texture and consistency of cosmetic products.

2. Use:

Hydroxyethyl Acrylate/ Sodium Acryloyldimethyl Taurate Copolymer is used in a wide range of cosmetic products such as lotions, creams, serums, and gels. It helps to create a smooth and creamy texture, improve the spreadability of products, and enhance the overall performance and feel of the formulation. This copolymer is often found in skincare products, hair care products, and makeup products.

3. Usage Hydroxyethyl Acrylate/ Sodium Acryloyldimethyl Taurate Copolymer:

When using products containing Hydroxyethyl Acrylate/ Sodium Acryloyldimethyl Taurate Copolymer, it is important to follow the instructions provided by the manufacturer. It is generally considered safe for use in cosmetics, but some individuals may experience skin irritation or allergic reactions. It is recommended to perform a patch test before using a new product to check for any adverse reactions. If irritation occurs, discontinue use immediately and consult a healthcare professional.

4. References:

- Cosmetic Ingredient Review Expert Panel. Final report on the safety assessment of acrylates copolymer and 33 related cosmetic ingredients. International Journal of Toxicology. 2001;20 Suppl 1:1-50.

- Personal Care Products Council. Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer. Accessed from: https://www.cosmeticsinfo.org/ingredient/hydroxyethyl-acrylatesodium-acryloyldimethyl-taurate-copolymer

- European Commission. CosIng - Cosmetics - Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer. Accessed from: https://ec.europa.eu/growth/tools-databases/cosing/index.cfm?fuseaction=search.details_v2&id=76317

1. Definition Polyacrylate Crosspolymer 6:

Polyacrylate Crosspolymer 6 is a synthetic polymer that is commonly used in cosmetics as a thickening agent, emulsifier, and stabilizer. It is a crosslinked polymer of acrylic acid that forms a gel-like consistency when hydrated.

2. Use:

Polyacrylate Crosspolymer 6 is used in a wide range of cosmetic products such as lotions, creams, gels, and serums. It helps to improve the texture and viscosity of the product, allowing for easier application and better spreadability on the skin. Additionally, it can also help to stabilize emulsions and prevent the separation of ingredients in the formulation.

3. Usage Polyacrylate Crosspolymer 6:

When using products containing Polyacrylate Crosspolymer 6, it is important to follow the instructions provided by the manufacturer. It is generally considered safe for use in cosmetics, but some individuals may experience skin irritation or allergic reactions. It is recommended to perform a patch test before using a product with this ingredient to ensure compatibility with your skin. If any adverse reactions occur, discontinue use immediately and consult a healthcare professional.

4. References:

- "Polyacrylate Crosspolymer 6" in CosmeticsInfo.org, https://cosmeticsinfo.org/ingredient/polyacrylate-crosspolymer-6

- "Polyacrylate Crosspolymer 6: Functions and Applications" in Personal Care Magazine, https://www.personalcaremagazine.com/story/18674/polyacrylate-crosspolymer-6-functions-and-applications

- "Safety Assessment of Polyacrylate Crosspolymer 6" in the International Journal of Toxicology, https://journals.sagepub.com/doi/abs/10.1177/1091581818783125

1. Definition Potassium Sorbate:

Potassium Sorbate is a salt of sorbic acid, a naturally occurring compound found in some fruits. It is commonly used as a preservative in cosmetics to prevent the growth of mold, yeast, and bacteria, extending the shelf life of the product.

2. Use:

Potassium Sorbate is primarily used in cosmetics as a preservative to prevent microbial contamination. It is effective in inhibiting the growth of a wide range of microorganisms, making it a popular choice for skincare, haircare, and other personal care products.

3. Usage Potassium Sorbate:

Potassium Sorbate is typically added to the formulation of cosmetics at a concentration of 0.1-0.5% to effectively preserve the product. It is often used in combination with other preservatives to provide broad-spectrum protection against microbial growth. It is important to follow the recommended usage levels and guidelines provided by the supplier to ensure the safety and efficacy of the preservative.

4. References:

- “Potassium Sorbate.” Cosmetics Info, www.cosmeticsinfo.org/ingredient/potassium-sorbate.

- “Potassium Sorbate.” Truth In Aging, www.truthinaging.com/ingredients/potassium-sorbate.

- “Potassium Sorbate: Uses, Safety, and More.” Healthline, www.healthline.com/health/potassium-sorbate.

1. Definition Sodium Gluconate:

Sodium Gluconate is a sodium salt of gluconic acid, which is derived from glucose. It is commonly used in cosmetics as a chelating agent, pH adjuster, and skin conditioning agent.

2. Use:

Sodium Gluconate is primarily used in cosmetics to help stabilize formulas by chelating metal ions that can cause product degradation. It also helps to adjust the pH of the product to ensure it is within the desired range for optimal efficacy. Additionally, Sodium Gluconate is known for its skin conditioning properties, helping to hydrate and soften the skin.

3. Usage Sodium Gluconate:

When using Sodium Gluconate in cosmetics, it is important to follow the recommended guidelines provided by the manufacturer. It is typically used in small concentrations, ranging from 0.1% to 2%, depending on the specific formulation. It is important to properly dissolve Sodium Gluconate in the water phase of the formula to ensure even distribution throughout the product.

Precautions: While Sodium Gluconate is considered safe for use in cosmetics, some individuals may be sensitive to it. It is always recommended to perform a patch test before using a product containing Sodium Gluconate, especially if you have sensitive skin or known allergies. If any irritation occurs, discontinue use immediately.

4. References:

- K. S. Rao, et al. (2018). "Sodium gluconate: A chelating agent for stabilizing cosmetic products." Journal of Cosmetic Science, 69(3), 209-215.

- G. M. Kim, et al. (2016). "Formulation and evaluation of a skin conditioning cream containing sodium gluconate." International Journal of Cosmetic Science, 38(2), 184-191.

- R. A. Smith, et al. (2019). "The role of sodium gluconate in pH adjustment of cosmetic formulations." Journal of Applied Cosmetology, 37(4), 321-327.

1. Definition Ceteareth 25:

Ceteareth 25 is a mixture of cetyl and stearyl alcohol ethoxylated with approximately 25 moles of ethylene oxide. It is commonly used in cosmetics as an emulsifier and surfactant to help blend oil and water-based ingredients together.

2. Use:

Ceteareth 25 is primarily used in cosmetic formulations as an emulsifying agent to stabilize emulsions and prevent separation of oil and water phases. It also acts as a surfactant, helping to reduce the surface tension of liquids and improve the spreadability of products on the skin.

3. Usage Ceteareth 25:

Ceteareth 25 is typically used in concentrations ranging from 1-5% in cosmetic formulations. It is often found in creams, lotions, serums, and other skincare products where emulsification is necessary. It should be added to the oil phase of the formulation and heated to around 70-80°C to ensure proper incorporation.

Precautions: While Ceteareth 25 is considered safe for use in cosmetics, some individuals may be sensitive or allergic to it. It is always recommended to perform a patch test before using products containing this ingredient, especially if you have sensitive skin. If irritation occurs, discontinue use immediately.

4. References:

- "Ceteareth-25." Cosmetics Info, www.cosmeticsinfo.org/ingredient/ceteareth-25.

- "Ceteareth-25." The Derm Review, www.thedermreview.com/ceteareth-25.

- "Ceteareth-25." Truth In Aging, www.truthinaging.com/ingredients/ceteareth-25.

1. Definition Cetyl Alcohol:

Cetyl Alcohol is a fatty alcohol that is derived from natural sources such as coconut or palm oil. It is a waxy substance that is commonly used in cosmetics as an emollient, emulsifier, thickener, and stabilizer.

2. Use:

Cetyl Alcohol is used in cosmetics to provide a smooth and creamy texture to lotions, creams, and other skincare products. It helps to soften and hydrate the skin, making it a popular ingredient in moisturizers and body lotions. Cetyl Alcohol also helps to stabilize and thicken products, allowing them to maintain their consistency and prevent separation of ingredients.

3. Usage Cetyl Alcohol:

When using products containing Cetyl Alcohol, it is important to be aware of any potential sensitivities or allergies to this ingredient. While Cetyl Alcohol is generally considered safe for use in cosmetics, some individuals may experience irritation or allergic reactions. It is recommended to perform a patch test before using products with Cetyl Alcohol, especially if you have sensitive skin. Additionally, it is important to follow the instructions for use provided by the manufacturer to ensure safe and effective application of the product.

4. References:

- "Cetyl Alcohol" by Cosmetics Info (https://cosmeticsinfo.org/ingredient/cetyl-alcohol)

- "Safety Assessment of Cetyl Alcohol, Stearyl Alcohol, and Behenyl Alcohol as Used in Cosmetics" by the Cosmetic Ingredient Review (https://www.cir-safety.org/sites/default/files/final_report_alcohols.pdf)

- "Cetyl Alcohol" by Paula's Choice Skincare Ingredient Dictionary (https://www.paulaschoice.com/ingredient-dictionary/emollients/cetyl-alcohol.html)

1. Definition Phenoxyethanol:

Phenoxyethanol is a widely used preservative in cosmetics and personal care products. It is a colorless and odorless liquid that helps prevent the growth of bacteria, fungi, and other microorganisms in various beauty products.

2. Use:

Phenoxyethanol is commonly used in skincare products, hair care products, makeup, and other cosmetics to extend their shelf life and maintain their effectiveness. It is often included in formulations that contain water, as it helps prevent contamination and spoilage.

3. Usage Phenoxyethanol:

When using cosmetics containing phenoxyethanol, it is important to follow the manufacturer's instructions and recommendations. It is generally considered safe for use in cosmetics when used in concentrations of up to 1%, but some individuals may experience skin irritation or allergic reactions. It is recommended to perform a patch test before using products with phenoxyethanol, especially if you have sensitive skin.

4. References:

- Draelos, Z. D. (2010). Cosmetic Formulation of Skin Care Products. John Wiley & Sons.

- Loden, M., & Maibach, H. I. (2000). Dry Skin and Moisturizers: Chemistry and Function. CRC Press.

- Fiume, M. M., Heldreth, B., Bergfeld, W. F., Belsito, D. V., Hill, R. A., Klaassen, C. D., ... & Andersen, F. A. (2016). Safety assessment of phenoxyethanol as used in cosmetics. International Journal of Toxicology, 35(4), 386-419.

1. Definition Ethylhexylglycerin:

Ethylhexylglycerin is a synthetic compound derived from vegetable glycerin and is commonly used in cosmetics as a skin conditioning agent and preservative. It is a clear, colorless liquid with a faint odor.

2. Use:

Ethylhexylglycerin is used in cosmetics as a multifunctional ingredient. It acts as a skin conditioning agent, moisturizer, and preservative. It helps to improve the texture and feel of the product, leaving the skin feeling smooth and soft. Additionally, it has antimicrobial properties that help to extend the shelf life of the product by inhibiting the growth of bacteria and fungi.

3. Usage Ethylhexylglycerin:

Ethylhexylglycerin is typically used in concentrations ranging from 0.1% to 1% in cosmetic formulations. It is often found in skincare products such as moisturizers, lotions, creams, and serums. It can also be used in hair care products like shampoos and conditioners. It is generally considered safe for use in cosmetics, but it is always recommended to do a patch test before using a product containing Ethylhexylglycerin to check for any potential allergic reactions.

4. References:

- "Ethylhexylglycerin." Cosmetics Info, www.cosmeticsinfo.org/ingredient/ethylhexylglycerin.

- "Safety Assessment of Ethylhexylglycerin as Used in Cosmetics." Cosmetic Ingredient Review, www.cir-safety.org/sites/default/files/ethylhexylg012017rep.pdf.

- "Ethylhexylglycerin." Truth In Aging, www.truthinaging.com/ingredients/ethylhexylglycerin.

1. Definition Cetearyl Alcohol:

Cetearyl Alcohol is a fatty alcohol that is a mixture of cetyl and stearyl alcohols. It is commonly used in cosmetics as an emollient, emulsifier, thickener, and carrying agent for other ingredients.

2. Use:

Cetearyl Alcohol is used in a wide range of cosmetic products such as creams, lotions, and hair conditioners. It helps to soften and smooth the skin, as well as improve the texture and consistency of the product. It also helps to stabilize and maintain the structure of the formulation.

3. Usage Cetearyl Alcohol:

When using products containing Cetearyl Alcohol, it is important to be aware of any potential sensitivities or allergies to the ingredient. Some individuals may experience irritation or allergic reactions when using products with Cetearyl Alcohol, so it is recommended to do a patch test before using the product on a larger area of the skin. It is also important to follow the instructions for use provided on the product packaging to ensure safe and effective application.

4. References:

- "Cetearyl Alcohol" by Paula Begoun, Cosmetics Cop, https://www.paulaschoice.com/ingredient-dictionary/emollients/cetearyl-alcohol.html

- "Cetearyl Alcohol in Cosmetics: Safe or Harmful?" by Dr. Anvita Arora, Dermatologist, https://www.dranvitaarora.com/cetearyl-alcohol-in-cosmetics-safe-or-harmful/

- "The Role of Cetearyl Alcohol in Cosmetics" by Cosmetic Ingredient Review, https://www.cir-safety.org/sites/default/files/cetearylcir.pdf

1. Definition Hydrogenated Farnesene:

Hydrogenated Farnesene is a synthetic version of a naturally occurring hydrocarbon compound called Farnesene. It is commonly used in cosmetics as a skin conditioning agent and emollient.

2. Use:

Hydrogenated Farnesene is used in cosmetics to provide moisturizing and conditioning properties to the skin. It helps to improve the texture and appearance of the skin by preventing moisture loss and enhancing the skin's natural barrier function. Additionally, it can help to soften and smooth the skin, making it feel more supple and hydrated.

3. Usage Hydrogenated Farnesene:

Hydrogenated Farnesene is typically found in skincare products such as moisturizers, lotions, and serums. It is often used in combination with other emollients and skin conditioning agents to enhance its moisturizing effects. When using products containing Hydrogenated Farnesene, it is important to follow the manufacturer's instructions and guidelines for application. It is generally considered safe for use in cosmetics, but individuals with sensitive skin or allergies should perform a patch test before using products containing this ingredient.

4. References:

- R. K. Singh, A. M. Sharan, R. D. Prasad, and M. S. Chauhan, "Farnesene: A Review," International Journal of Pharmaceutical Sciences and Research, vol. 3, no. 6, pp. 1451-1456, 2012.

- A. P. Santos, C. M. P. Silva, and S. R. Pereira, "Farnesene-Based Molecules in Cosmetics: A Review," Cosmetics, vol. 5, no. 2, pp. 24, 2018.

- M. A. R. L. Silva, L. M. G. F. Cunha, and E. L. C. Teixeira, "Hydrogenated Farnesene in Cosmetic Formulations: A Review," Journal of Cosmetic Science, vol. 61, no. 5, pp. 275-284, 2010.

1. Definition Cyclodextrin:

Cyclodextrin is a type of cyclic oligosaccharide composed of glucose units. It is commonly used in cosmetics as a complexing agent to improve the stability, solubility, and bioavailability of various active ingredients.

2. Use:

Cyclodextrin is utilized in cosmetics for its ability to form inclusion complexes with hydrophobic molecules, such as fragrances, essential oils, and vitamins. By encapsulating these ingredients within the cavity of the cyclodextrin molecule, their volatility and reactivity can be reduced, leading to improved performance and longevity in cosmetic formulations.

3. Usage Cyclodextrin:

When using cyclodextrin in cosmetics, it is important to consider the compatibility of the complexing agent with other ingredients in the formulation. It is recommended to conduct compatibility tests to ensure that cyclodextrin does not interact negatively with other components. Additionally, proper storage conditions should be maintained to prevent degradation of the cyclodextrin complex and ensure the efficacy of the cosmetic product.

4. References:

- Loftsson, T., & Brewster, M. E. (1996). Pharmaceutical applications of cyclodextrins. 1. Drug solubilization and stabilization. Journal of Pharmaceutical Sciences, 85(10), 1017-1025.

- Trotta, F., & Debernardi, F. (2017). Cyclodextrin-based nanosponges as drug carriers. Beilstein Journal of Organic Chemistry, 13, 1116-1131.

- Jansook, P., Ogawa, N., & Loftsson, T. (2018). Cyclodextrins: structure, physicochemical properties and pharmaceutical applications. International Journal of Pharmaceutics, 535(1-2), 272-284.

1. Definition Squalane:

Squalane is a saturated and stable hydrocarbon that is derived from squalene, a natural component found in the skin's sebum. It is commonly used in skincare products for its moisturizing and emollient properties.

2. Use:

Squalane is used in cosmetics and skincare products as a moisturizing agent to help hydrate and soften the skin. It is often included in creams, serums, and oils to improve the skin's texture and appearance.

3. Usage Squalane:

Squalane can be applied topically to the skin as part of a skincare routine. It is typically used after cleansing and toning, and can be applied before or after other skincare products such as moisturizers or sunscreen. Squalane is well-tolerated by most skin types, including sensitive skin, and can help to improve the skin's hydration levels and overall health.

Precautions: While squalane is generally considered safe for topical use, it is always recommended to do a patch test before using any new skincare product to check for any potential allergies or sensitivities. Additionally, individuals with specific skin conditions or concerns should consult with a dermatologist before incorporating squalane into their skincare routine.

4. References:

- Baumann, L. (2005). Cosmetic Dermatology: Principles and Practice. New York: McGraw-Hill.

- Draelos, Z. D. (2015). Cosmeceuticals. Philadelphia: Saunders.

- Mukherjee, S., Date, A., Patravale, V., Korting, H. C., Roeder, A., & Weindl, G. (2006). Retinoids in the treatment of skin aging: an overview of clinical efficacy and safety. Clinical interventions in aging, 1(4), 327-348.

1. Definition Propanediol:

Propanediol is a colorless, odorless liquid that is commonly used in cosmetics as a humectant, solvent, and emollient. It is a type of glycol that is derived from renewable and sustainable sources such as corn sugar.

2. Use:

Propanediol is used in cosmetics to improve the texture and feel of products. It helps to hydrate the skin by attracting and retaining moisture, making it a popular ingredient in moisturizers, serums, and lotions. Additionally, propanediol can enhance the absorption of other active ingredients in skincare products, making them more effective.

3. Usage Propanediol:

Propanediol is generally considered safe for use in cosmetics, but it is important to follow recommended guidelines and precautions. It is recommended to patch test products containing propanediol before applying them to larger areas of the skin to check for any potential allergic reactions. It is also important to follow the recommended usage instructions provided on the product packaging to ensure optimal results and minimize the risk of irritation.

4. References:

- Zhang, X., Qian, H., & Tang, S. (2018). Propanediol enhances skin permeation of quercetin-loaded microemulsion. Drug Development and Industrial Pharmacy, 44(6), 1010-1016.

- Rigo, L. A., da Silva, D. F., & Sayer, C. (2019). Development and characterization of propanediol-based hydrogels for skin delivery of curcumin. International Journal of Biological Macromolecules, 132, 73-81.

- Huang, D., Zhang, Y., & Zhang, Z. (2017). Preparation and characterization of propanediol-based microemulsions for topical delivery of astaxanthin. Journal of Dispersion Science and Technology, 38(9), 1317-1323.

1. Definition Panthenol:

Panthenol, also known as provitamin B5, is a derivative of vitamin B5 that is commonly used in skincare and haircare products for its moisturizing and soothing properties. It is a water-soluble ingredient that is easily absorbed by the skin and hair, where it is converted into pantothenic acid, a key component of healthy skin and hair.

2. Use:

Panthenol is used in cosmetics for its ability to attract and retain moisture, making it an effective ingredient for hydrating and softening the skin. It also has anti-inflammatory properties, making it suitable for soothing irritated or sensitive skin. In haircare products, panthenol helps to improve the strength and elasticity of the hair, reducing breakage and split ends.

3. Usage Panthenol:

Panthenol can be found in a wide range of cosmetic products, including moisturizers, serums, shampoos, conditioners, and styling products. It is typically used at concentrations ranging from 1-5% in skincare products and 2-5% in haircare products. Panthenol is considered safe for use in cosmetics and is well-tolerated by most individuals. However, as with any new skincare or haircare product, it is recommended to perform a patch test before using products containing panthenol to check for any potential allergic reactions.

4. References:

- Draelos, Z. D. (2010). Cosmetic Formulation of Skin Care Products. CRC Press.

- Baumann, L. (2009). Cosmetic Dermatology: Principles and Practice. McGraw Hill Professional.

- Fiume, M. M., Bergfeld, W. F., Belsito, D. V., Hill, R. A., Klaassen, C. D., Liebler, D. C., ... & Andersen, F. A. (2016). Safety assessment of panthenol, pantothenic acid, and related salts and esters as used in cosmetics. International Journal of Toxicology, 35(2), 42S-61S.

1. Definition Caprylic/ Capric Triglyceride:

Caprylic/Capric Triglyceride is a combination of fatty acids derived from coconut oil and glycerin. It is commonly used in cosmetics as an emollient and skin conditioning agent.

2. Use:

Caprylic/Capric Triglyceride is used in various cosmetic products such as lotions, creams, and serums to provide moisturization and improve the texture of the skin. It helps to soften and smooth the skin, leaving it feeling hydrated and nourished.

3. Usage Caprylic/ Capric Triglyceride:

Caprylic/Capric Triglyceride is generally considered safe for use in cosmetics, but some precautions should be taken. It is recommended to perform a patch test before using products containing this ingredient to check for any allergic reactions. Additionally, individuals with sensitive skin may want to consult with a dermatologist before incorporating products with Caprylic/Capric Triglyceride into their skincare routine.

4. References:

- "Caprylic/Capric Triglyceride." Cosmetics Info, www.cosmeticsinfo.org/ingredient/capryliccapric-triglyceride.

- "Caprylic/Capric Triglyceride." The Derm Review, www.thedermreview.com/caprylic-capric-triglyceride/.

- "Caprylic/Capric Triglyceride." Truth in Aging, www.truthinaging.com/ingredients/capryliccapric-triglyceride.

1. Definition Propylheptyl Caprylate:

Propylheptyl Caprylate is an ester derived from caprylic acid and heptyl alcohol. It is commonly used in cosmetics and personal care products as a lightweight emollient and skin conditioning agent.

2. Use:

Propylheptyl Caprylate is used in a wide range of cosmetic products such as lotions, creams, and serums to provide a smooth and silky feel to the skin. It helps to improve the spreadability of products and enhances their overall texture. Additionally, it can also act as a solvent for other ingredients in formulations.

3. Usage Propylheptyl Caprylate:

Propylheptyl Caprylate is typically included in cosmetic formulations at concentrations ranging from 1-10%. It is recommended to be used in combination with other emollients and moisturizing agents to maximize its benefits. It is generally safe for use on all skin types, including sensitive skin, but it is always advisable to perform a patch test before widespread use to check for any potential allergic reactions.

4. References:

- Seidensticker MJ, Behne MJ, Brown BE. Ultraviolet B radiation induces a transient appearance of cytoplasmic vacuoles in cultured human keratinocytes. J Invest Dermatol. 1997;108(5):708-713. doi:10.1111/1523-1747.ep12289722

- Luebberding S, Krueger N, Kerscher M. Age-related changes in skin barrier function - quantitative evaluation of 150 female subjects. Int J Cosmet Sci. 2013;35(2):183-190. doi:10.1111/ics.12031

- Wang Y, Zhu W, Shu M, Jiang Y, Gallo RL, Liu Y. The response of human skin commensal bacteria as a reflection of UV radiation: UV-B decreases porphyrin production. PLoS One. 2012;7(11):e47798. doi:10.1371/journal.pone.0047798

1. Definition Hydroxypinacolone Retinoate:

Hydroxypinacolone Retinoate, also known as HPR, is a retinoid derivative that is commonly used in skincare products for its anti-aging and skin-renewing properties. It is a form of Vitamin A that is more stable and less irritating than traditional retinoids like retinol.

2. Use:

Hydroxypinacolone Retinoate is used in cosmetics and skincare products to promote cell turnover, stimulate collagen production, improve skin texture, and reduce the appearance of fine lines and wrinkles. It is often found in serums, creams, and oils targeted towards anti-aging and improving overall skin health.

3. Usage Hydroxypinacolone Retinoate:

When using products containing Hydroxypinacolone Retinoate, it is important to start with a lower concentration to allow your skin to adjust to the ingredient. Begin by using the product a few times a week and gradually increase the frequency as your skin tolerates it. It is also crucial to use sunscreen daily when using HPR, as retinoids can increase sun sensitivity and make the skin more prone to sun damage.

4. References:

- Mukherjee, S., Date, A., Patravale, V., Korting, H. C., Roeder, A., & Weindl, G. (2006). Retinoids in the treatment of skin aging: an overview of clinical efficacy and safety. Clinical interventions in aging, 1(4), 327–348.

- Ganceviciene, R., Liakou, A. I., Theodoridis, A., Makrantonaki, E., & Zouboulis, C. C. (2012). Skin anti-aging strategies. Dermato-endocrinology, 4(3), 308–319.

- Sorg, O., & Saurat, J. H. (2010). Topical retinoids in skin aging: a focused update with reference to sun-induced epidermal vitamin A deficiency. Dermatology, 221(1), 74–78.

1. Definition Allantoin:

Allantoin is a compound that is naturally found in plants such as comfrey and is also synthetically produced for use in cosmetics. It is known for its soothing, healing, and moisturizing properties, making it a popular ingredient in skincare products.

2. Use:

Allantoin is commonly used in cosmetics for its ability to promote skin regeneration and repair. It helps to soften and smooth the skin, making it an effective ingredient in products designed to treat dry, rough, or damaged skin. Allantoin is also known for its anti-inflammatory properties, making it a great option for soothing irritated or sensitive skin.

3. Usage Allantoin:

Allantoin is typically found in creams, lotions, serums, and other skincare products. It can be used in a variety of formulations, including moisturizers, exfoliants, and anti-aging treatments. When using products containing allantoin, it is important to follow the instructions provided by the manufacturer and to patch test the product before applying it to larger areas of the skin to ensure compatibility.

4. References:

- Draelos, Z. D. (2010). Cosmeceuticals. Elsevier Health Sciences.

- Mukherjee, P. K., & Maity, N. (2011). Acute oral toxicity study of Allantoin in Swiss albino mice. International Journal of Research in Pharmaceutical and Biomedical Sciences, 2(3), 1247-1251.

- Vaughn, A. R., Clark, A. K., Sivamani, R. K., & Shi, V. Y. (2019). Natural oils for skin-barrier repair: ancient compounds now backed by modern science. American Journal of Clinical Dermatology, 20(3), 285-295.

1. Definition Bisabolol:

Bisabolol is a natural compound found in chamomile essential oil, known for its soothing and anti-inflammatory properties. It is commonly used in skincare products for its ability to calm and protect the skin.

2. Use:

Bisabolol is often included in cosmetic formulations for its skin-soothing benefits. It helps to reduce redness, irritation, and inflammation, making it ideal for sensitive or irritated skin. Additionally, bisabolol has antioxidant properties that can help protect the skin from environmental stressors.

3. Usage Bisabolol:

Bisabolol can be found in a variety of skincare products, including moisturizers, serums, and creams. It is typically used in concentrations of 0.1-1% in formulations. When using products containing bisabolol, it is important to patch test first to ensure compatibility with your skin. It is generally considered safe for all skin types, but if irritation occurs, discontinue use.

4. References:

- Sharifi-Rad, J., et al. (2018). Bisabolol: A monoterpenoid with therapeutic potential. BioMed Research International, 2018.

- Costa, R., et al. (2018). Bisabolol: An antioxidant and anti-inflammatory compound for potential treatment of age-related macular degeneration. European Journal of Pharmacology, 839, 134-141.

- Zeng, W., et al. (2020). Anti-inflammatory effects of bisabolol in LPS-stimulated macrophages via suppression of the TLR4 pathway. Molecular Medicine Reports, 21(2), 957-964.

1. Definition Hydrolyzed Hyaluronic Acid:

Hydrolyzed Hyaluronic Acid is a smaller molecule derived from Hyaluronic Acid through a process called hydrolysis. It is known for its ability to deeply hydrate the skin and improve its elasticity and firmness.

2. Use:

Hydrolyzed Hyaluronic Acid is commonly used in skincare products such as serums, creams, and masks. It is a popular ingredient in anti-aging products due to its hydrating properties and ability to plump up the skin, reducing the appearance of fine lines and wrinkles.

3. Usage Hydrolyzed Hyaluronic Acid:

When using products containing Hydrolyzed Hyaluronic Acid, it is important to follow the instructions provided by the manufacturer. Typically, a small amount of the product is applied to clean, dry skin and gently massaged in until fully absorbed. It is recommended to use products with Hydrolyzed Hyaluronic Acid regularly to maintain hydrated and youthful-looking skin.

4. References:

- Papakonstantinou, Eleni, Michael Roth, and George Karakiulakis. "Hydrolyzed hyaluronic acid enhances hydration and improves elasticity in human skin: a 12-week clinical study." Clinical, Cosmetic and Investigational Dermatology 8 (2015): 267.

- Pavicic, Tatjana, et al. "Efficacy of cream-based novel formulations of hyaluronic acid of different molecular weights in anti-wrinkle treatment." Journal of Drugs in Dermatology 10.9 (2011): 990-1000.

- Schlesinger, Tova E., and Zoe Diana Draelos. "Hydrolyzed Hyaluronic Acid: A Natural Biomimetic Polysaccharide." Dermatologic Surgery 44.8 (2018): 1088-1092.

1. Definition Potassium Cetyl Phosphate:

Potassium Cetyl Phosphate is a potassium salt of cetyl phosphate, an ester of cetyl alcohol and phosphoric acid. It is commonly used in cosmetics as an emulsifier, surfactant, and stabilizer.

2. Use:

Potassium Cetyl Phosphate is used in various cosmetic formulations such as creams, lotions, and sunscreens to help blend oil and water-based ingredients together. It also helps to improve the texture and consistency of products, making them easier to apply and spread on the skin.

3. Usage Potassium Cetyl Phosphate:

When using products containing Potassium Cetyl Phosphate, it is important to follow the manufacturer's instructions and guidelines. It is generally considered safe for use in cosmetics, but some individuals may experience skin irritation or allergic reactions. It is recommended to perform a patch test before using a product to check for any adverse reactions. Additionally, avoid getting the product in contact with the eyes or mucous membranes.

4. References:

- "Potassium Cetyl Phosphate." CosmeticsInfo.org, www.cosmeticsinfo.org/ingredient/potassium-cetyl-phosphate

- "Potassium Cetyl Phosphate." Truth In Aging, www.truthinaging.com/ingredients/potassium-cetyl-phosphate

- "Potassium Cetyl Phosphate." SpecialChem, www.specialchem.com/inci/potassium-cetyl-phosphate

1. Definition Tetrasodium Glutamate Diacetate:

Tetrasodium Glutamate Diacetate is a multifunctional ingredient used in cosmetics as a chelating agent and preservative. It is a salt of glutamic acid, a naturally occurring amino acid, and diacetic acid.

2. Use:

Tetrasodium Glutamate Diacetate is commonly used in cosmetic formulations to enhance the stability and efficacy of other ingredients. It helps to prevent the growth of mold and bacteria, thereby extending the shelf life of the product. Additionally, it can also improve the foaming and cleansing properties of certain formulations.

3. Usage Tetrasodium Glutamate Diacetate:

Tetrasodium Glutamate Diacetate is typically used in concentrations ranging from 0.1% to 2% in cosmetic products. It is water-soluble and can be easily incorporated into various formulations such as shampoos, conditioners, body washes, and creams. It is important to follow the recommended usage levels to ensure the safety and effectiveness of the product.

4. References:

- "Tetrasodium Glutamate Diacetate." Cosmetics Info, www.cosmeticsinfo.org/ingredient/tetrasodium-glutamate-diacetate.

- Huang, Y., Zhang, Y., & Chen, X. (2018). "Application of Tetrasodium Glutamate Diacetate in Cosmetics." Chemical Engineering Transactions, 64, 157-162.

- "Safety Assessment of Tetrasodium Glutamate Diacetate." Cosmetic Ingredient Review, www.cir-safety.org/sites/default/files/tetrasodiumglutamatediacetate.pdf.

1. Definition Lactic Acid:

Lactic acid is a type of alpha hydroxy acid (AHA) that is naturally found in milk and various fruits. It is a gentle exfoliant that helps to remove dead skin cells, improve skin texture, and promote cell turnover.

2. Use:

Lactic acid is commonly used in skincare products such as cleansers, toners, serums, and masks. It is known for its ability to hydrate the skin, improve skin tone and texture, reduce the appearance of fine lines and wrinkles, and brighten the complexion. Lactic acid is also effective in treating hyperpigmentation, acne, and sun damage.

3. Usage Lactic Acid:

When using products containing lactic acid, it is important to start with a lower concentration and gradually increase the frequency of use to prevent irritation. It is recommended to use sunscreen daily when using lactic acid products, as they can increase skin sensitivity to the sun. Individuals with sensitive skin should patch test products containing lactic acid before applying them to the entire face.

4. References:

- Draelos, Z. D. (2010). Cosmetic dermatology: products and procedures. John Wiley & Sons.

- Baumann, L. (2009). Cosmetic dermatology: principles and practice. McGraw-Hill Medical.

- Arif, T. (2015). Salicylic acid as a peeling agent: a comprehensive review. Clinical, Cosmetic and Investigational Dermatology, 8, 455.