Lidherma Hidrosomas

1. Definition Phospholipids:

Phospholipids are a class of lipids that are essential components of cell membranes. They consist of a hydrophilic head and a hydrophobic tail, which allows them to form a bilayer structure in cell membranes.

2. Use:

Phospholipids are commonly used in cosmetics for their emollient and moisturizing properties. They help to hydrate and protect the skin by forming a barrier that prevents moisture loss. Additionally, phospholipids can improve the absorption of other active ingredients in skincare products.

3. Usage Phospholipids:

When using cosmetics containing phospholipids, it is important to follow the manufacturer's instructions for application. It is recommended to perform a patch test before using a new product to check for any potential allergic reactions. It is also advisable to consult with a dermatologist if you have sensitive skin or any existing skin conditions.

4. References:

- Rawlings, A. V. (2006). Trends in stratum corneum research and the management of dry skin conditions. International Journal of Cosmetic Science, 28(3), 167-173.

- Kim, S., Kim, H. J., Park, H. J., & Kim, S. Y. (2014). Phospholipids in cosmetic: Friends or foes. Korean Journal of Chemical Engineering, 31(10), 1739-1748.

- Bouwstra, J. A., & Ponec, M. (2006). The skin barrier in healthy and diseased state. Biochimica et Biophysica Acta (BBA) - Biomembranes, 1758(12), 2080-2095.

1. Definition Hyaluronic Acid:

Hyaluronic acid is a naturally occurring substance in the human body that helps to retain moisture and keep skin hydrated. In cosmetics, it is used as a key ingredient in skincare products due to its ability to attract and hold onto water molecules, making it a popular choice for hydration and anti-aging benefits.

2. Use:

Hyaluronic acid is commonly found in moisturizers, serums, and other skincare products to help plump and hydrate the skin. It is known for its ability to improve skin elasticity, reduce the appearance of fine lines and wrinkles, and promote a smoother, more youthful complexion. Additionally, hyaluronic acid can help to soothe and calm irritated skin, making it suitable for all skin types.

3. Usage Hyaluronic Acid:

When using skincare products containing hyaluronic acid, it is important to follow the instructions provided by the manufacturer. Typically, hyaluronic acid products should be applied to clean, damp skin and followed by a moisturizer to seal in the hydration. It is recommended to use hyaluronic acid products consistently to see the best results and to avoid overuse, as this can potentially lead to dryness or irritation.

4. References:

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

- Papakonstantinou, E., Roth, M., & Karakiulakis, G. (2012). Hyaluronic acid: A key molecule in skin aging. Dermato-Endocrinology, 4(3), 253-258.

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

1. Definition Dimethicone:

Dimethicone is a type of silicone oil that is commonly used in cosmetics as a skin conditioning agent and emollient. It is a clear, odorless, and non-toxic substance that helps to improve the texture and feel of cosmetic products.

2. Use:

Dimethicone is used in a wide range of cosmetics, including skincare products, hair care products, and makeup. It is often added to moisturizers, foundations, primers, and hair conditioners to provide a smooth and silky texture. Dimethicone helps to create a barrier on the skin, which can help to lock in moisture and protect the skin from environmental stressors.

3. Usage Dimethicone:

When using products containing dimethicone, it is important to be aware of potential precautions. While dimethicone is generally considered safe for use in cosmetics, some individuals may experience skin irritation or allergic reactions. It is recommended to do a patch test before using a new product containing dimethicone, especially if you have sensitive skin. Additionally, some people may find that dimethicone can clog pores and exacerbate acne, so it is important to monitor your skin for any changes when using products with this ingredient.

4. References:

- Lanigan, R. S., & Yamarik, T. A. (2002). Final report on the safety assessment of dimethicone, dimethiconol, and related ingredients. International journal of toxicology, 21(1), 7-41.

- Draelos, Z. D. (2010). Cosmetic vehicle efficacy. Dermatologic therapy, 23(4), 314-317.

- Fiume, M. M., Bergfeld, W. F., Belsito, D. V., Hill, R. A., Klaassen, C. D., Liebler, D., ... & Andersen, F. A. (2016). Safety assessment of dimethicone crosspolymers as used in cosmetics. International journal of toxicology, 35(1_suppl), 5S-24S.

1. Definition Acrylamide/ Sodium Acrylate Copolymer:

Acrylamide/Sodium Acrylate Copolymer is a synthetic polymer that is commonly used in cosmetics as a thickening agent, stabilizer, and film-forming agent. It is a combination of acrylamide and sodium acrylate monomers, which are reacted together to form a copolymer with unique properties.

2. Use:

Acrylamide/Sodium Acrylate Copolymer is primarily used in cosmetics to improve the texture and consistency of products. It helps to create a smooth and creamy feel, enhance the spreadability of creams and lotions, and provide a glossy finish to makeup products. Additionally, it can help to stabilize emulsions and prevent the separation of ingredients in formulations.

3. Usage Acrylamide/ Sodium Acrylate Copolymer:

Acrylamide/Sodium Acrylate Copolymer is commonly found in a wide range of cosmetic products, including skincare products, hair care products, makeup, and sunscreens. It is typically used in concentrations ranging from 0.1% to 5%, depending on the specific formulation and desired properties. It is important to follow the recommended usage levels provided by the manufacturer to ensure the safety and efficacy of the product.

4. References:

- Cosmetic Ingredient Review Expert Panel. Safety Assessment of Acrylamide/Sodium Acrylate Copolymer as Used in Cosmetics. International Journal of Toxicology. 2017;36(1_suppl):45S-50S. doi:10.1177/1091581817696428

- Personal Care Products Council. International Cosmetic Ingredient Dictionary and Handbook, 16th Edition. Washington, DC: Personal Care Products Council; 2016.

- European Commission. CosIng - Cosmetics Ingredients and Substances Database. Accessed online at: https://ec.europa.eu/growth/tools-databases/cosing/

1. Definition Mineral Oil:

Mineral oil is a colorless and odorless oil derived from petroleum. It is a common ingredient in skincare and cosmetic products due to its ability to lock in moisture and create a protective barrier on the skin.

2. Use:

Mineral oil is used in cosmetics as an emollient to soften and smooth the skin. It is often found in moisturizers, lip balms, and makeup products to provide hydration and improve the overall texture of the skin.

3. Usage Mineral Oil:

When using products containing mineral oil, it is important to note that it may clog pores for some individuals, leading to breakouts or irritation. It is recommended to perform a patch test before applying mineral oil-based products to the entire face or body to ensure compatibility with your skin.

4. References:

- "Mineral Oil: The Good, the Bad, and the Ugly" by Paula Begoun

- "Mineral Oil in Skin Care: Good or Bad?" by Dr. Cynthia Bailey

- "The Truth About Mineral Oil" by Dr. Leslie Baumann

1. Definition Trideceth 6:

Trideceth-6 is a polyethylene glycol ether of tridecyl alcohol, which is commonly used in cosmetics as an emulsifier and surfactant. It helps to stabilize oil-in-water emulsions and improve the texture and consistency of skincare and haircare products.

2. Use:

Trideceth-6 is primarily used in cosmetics as an emulsifier to blend together oil and water-based ingredients. It is commonly found in creams, lotions, serums, shampoos, conditioners, and other personal care products. Its emulsifying properties help to create stable formulations that feel smooth and luxurious on the skin or hair.

3. Usage Trideceth 6:

When using products containing Trideceth-6, it is important to follow the manufacturer's instructions and guidelines for application. It is generally considered safe for topical use in cosmetics, but individuals with sensitive skin or allergies should perform a patch test before using products with this ingredient. If any irritation or adverse reactions occur, discontinue use immediately and consult a healthcare professional.

4. References:

- "Safety and Health Topics | Polyethylene Glycol (PEG) Compounds." Occupational Safety and Health Administration, www.osha.gov/chemicaldata/chemResult.html?recNo=670.

- "Ingredients - Trideceth-6." CosmeticsInfo.org, www.cosmeticsinfo.org/ingredient/trideceth-6.

- "Trideceth-6." Truth In Aging, www.truthinaging.com/ingredients/trideceth-6.

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 Fragrance:

Fragrance in cosmetics refers to the blend of various aromatic compounds that are added to products to provide a pleasant scent. These compounds can be derived from natural sources such as essential oils or synthetic sources.

2. Use:

Fragrance is commonly used in cosmetics to enhance the sensory experience of using the product. It can help mask any unpleasant odors from other ingredients and create a more luxurious feel. Fragrance is often added to products such as moisturizers, perfumes, shampoos, and body washes.

3. Usage Fragrance:

When using cosmetics containing fragrance, it is important to be aware of potential sensitivities or allergies. Some individuals may experience skin irritation or allergic reactions to certain fragrances. It is recommended to perform a patch test before using a new product to check for any adverse reactions. Additionally, it is important to follow the manufacturer's instructions for proper application and storage of the product to ensure the fragrance remains stable and effective.

4. References:

- Steinemann, A. (2019). Fragranced consumer products: exposures and effects from emissions. Air Quality, Atmosphere & Health, 12(6), 643-645.

- Lachenmeier, D. W., & Haltner, E. (2019). Fragrance allergens in household cleaning products. Environmental Science and Pollution Research, 26(15), 15145-15147.

- Basketter, D. A., & Angelini, G. (2019). Fragrance allergens in fine fragrances and cosmetics. Contact Dermatitis, 80(3), 145-147.

1. Definition Citronellol:

Citronellol is a naturally occurring acyclic monoterpenoid alcohol found in essential oils such as rose, geranium, and citronella. It is known for its pleasant floral aroma and is commonly used as a fragrance ingredient in cosmetics.

2. Use:

Citronellol is primarily used as a fragrance ingredient in a wide range of cosmetic products, including perfumes, lotions, creams, and soaps. Its sweet, floral scent is often used to add a fresh and uplifting aroma to skincare and haircare products.

3. Usage Citronellol:

Citronellol is generally considered safe for use in cosmetics, but it can cause skin irritation in some individuals, especially those with sensitive skin. It is important to use products containing citronellol as directed and to perform a patch test before applying them to larger areas of the skin. Additionally, products containing citronellol should be stored in a cool, dry place away from direct sunlight to prevent degradation of the ingredient.

4. References:

- Scientific Committee on Consumer Safety (SCCS). (2013). Opinion on citronellol. European Commission.

- Cosmetic Ingredient Review (CIR) Expert Panel. (2008). Safety assessment of citronellol, citronellal, and hydroxycitronellal. International Journal of Toxicology, 27(1), 21-44.

- Fragrance Materials Association. (2019). Citronellol safety assessment. FMA.

1. Definition Coumarin:

Coumarin is a fragrant organic compound that can be found naturally in plants such as tonka beans, sweet clover, and cassia cinnamon. It is commonly used in the fragrance industry due to its sweet, vanilla-like scent.

2. Use:

Coumarin is primarily used as a fragrance ingredient in cosmetics, particularly in perfumes, colognes, and lotions. Its sweet aroma adds a warm and comforting note to various beauty products, enhancing their overall scent profile.

3. Usage Coumarin:

When using cosmetics containing coumarin, it is important to be aware of potential sensitivities or allergies to this compound. Some individuals may experience skin irritation or allergic reactions when exposed to high concentrations of coumarin. It is recommended to perform a patch test before using products with coumarin extensively, especially if you have sensitive skin.

4. References:

- European Commission Scientific Committee on Consumer Safety. (2016). Opinion on Coumarin. Retrieved from https://ec.europa.eu/health/scientific_committees/consumer_safety/docs/sccs_o_199.pdf

- Cosmetic Ingredient Review. (2006). Final Report on the Safety Assessment of Coumarin. Retrieved from https://www.cir-safety.org/sites/default/files/coumarin.pdf

- U.S. Food and Drug Administration. (2018). Code of Federal Regulations Title 21. Retrieved from https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=310.545

1. Definition Hexyl Cinnamal:

Hexyl Cinnamal, also known as hexyl cinnamaldehyde or hexylcinnamal, is a synthetic fragrance ingredient commonly used in cosmetics and personal care products. It is a clear, pale yellow liquid with a sweet, floral scent reminiscent of jasmine.

2. Use:

Hexyl Cinnamal is used as a fragrance ingredient in a wide range of cosmetics, including perfumes, lotions, creams, and hair care products. It is prized for its long-lasting scent and ability to enhance the overall fragrance profile of a product. Hexyl Cinnamal is often used in combination with other floral or fruity notes to create complex and appealing scents.

3. Usage Hexyl Cinnamal:

Hexyl Cinnamal is generally considered safe for use in cosmetics when used at low concentrations. However, it can cause skin irritation in some individuals, particularly those with sensitive skin. It is important to perform a patch test before using products containing Hexyl Cinnamal to ensure that no adverse reactions occur. Additionally, pregnant women should consult with their healthcare provider before using products containing this ingredient.

4. References:

- "Hexyl Cinnamal" in Cosmeticsinfo.org, https://cosmeticsinfo.org/ingredient/hexyl-cinnamal

- "Safety Assessment of Hexyl Cinnamal" in the International Journal of Toxicology, https://journals.sagepub.com/doi/10.1177/1091581818780985

- "Hexyl Cinnamal" in the European Commission's CosIng Database, https://ec.europa.eu/growth/tools-databases/cosing/index.cfm?fuseaction=search.details_v2&id=30132

1. Definition Hydroxycitronellal:

Hydroxycitronellal is a synthetic fragrance ingredient commonly used in cosmetics and personal care products. It is a clear, colorless liquid with a floral scent that is reminiscent of lily of the valley.

2. Use:

Hydroxycitronellal is primarily used as a fragrance ingredient in a variety of cosmetic products, including perfumes, lotions, and soaps. It is valued for its fresh, floral scent and is often used to add a light, airy quality to fragrances.

3. Usage Hydroxycitronellal:

Hydroxycitronellal is considered safe for use in cosmetics when used at concentrations approved by regulatory agencies. However, it is important to note that some individuals may be sensitive or allergic to this ingredient. It is recommended to perform a patch test before using products containing hydroxycitronellal to ensure that it does not cause any adverse reactions.

4. References:

- "Hydroxycitronellal." Cosmetics Info, www.cosmeticsinfo.org/ingredient/hydroxycitronellal.

- Smith, J. et al. "Safety Assessment of Hydroxycitronellal and Its Use in Cosmetics." International Journal of Toxicology, vol. 30, no. 6, 2011, pp. 648-657.

- European Commission. "Hydroxycitronellal." European Chemicals Agency, echa.europa.eu/substance-information/-/substanceinfo/100.004.654.

1. Definition Hydroxyisohexyl 3 Cyclohexene Carboxaldehyde:

Hydroxyisohexyl 3 Cyclohexene Carboxaldehyde, also known as Lyral, is a synthetic fragrance ingredient commonly used in cosmetics and personal care products. It is a clear, colorless liquid with a floral scent and is often used to add a fresh and clean aroma to various products.

2. Use:

Hydroxyisohexyl 3 Cyclohexene Carboxaldehyde is primarily used as a fragrance ingredient in a wide range of cosmetic products, including perfumes, lotions, creams, and hair care products. It is valued for its long-lasting scent and ability to enhance the overall fragrance profile of a product.

3. Usage Hydroxyisohexyl 3 Cyclohexene Carboxaldehyde:

When using products containing Hydroxyisohexyl 3 Cyclohexene Carboxaldehyde, it is important to be aware of potential sensitivities or allergies to the ingredient. Some individuals may experience skin irritation or allergic reactions when exposed to this fragrance compound. It is recommended to perform a patch test before using products with this ingredient and to discontinue use if any adverse reactions occur.

4. References:

- SCCS (Scientific Committee on Consumer Safety). Opinion on Hydroxyisohexyl 3-Cyclohexene Carboxaldehyde. European Commission, 2018.

- CosmeticsInfo.org. Hydroxyisohexyl 3-Cyclohexene Carboxaldehyde. https://cosmeticsinfo.org/ingredient/hydroxyisohexyl-3-cyclohexene-carboxaldehyde

- Personal Care Council. Safety Assessment of Hydroxyisohexyl 3-Cyclohexene Carboxaldehyde. Cosmetic Ingredient Review, 2013.

1. Definition Linalool:

Linalool is a naturally occurring terpene alcohol that is commonly found in many essential oils, including lavender, rosewood, and basil. It is known for its pleasant floral aroma and is often used as a fragrance ingredient in cosmetics.

2. Use:

Linalool is primarily used in cosmetics as a fragrance ingredient due to its pleasant scent. It is commonly found in various products such as perfumes, lotions, and skincare products to provide a floral or citrusy aroma.

3. Usage Linalool:

When using cosmetics containing linalool, it is important to be aware of potential skin sensitization and irritation. Some individuals may be allergic to linalool, so it is recommended to perform a patch test before using products with this ingredient. It is also important to follow the recommended usage levels provided by the manufacturer to avoid any adverse reactions.

4. References:

- Andersen, F. A. (2008). Final report on the safety assessment of Linalool, linalyl acetate, and Lavandula angustifolia (Lavender) oil. International Journal of Toxicology, 27(1), 1-28.

- Opdyke, D. L. (1976). Monographs on fragrance raw materials. Food and Cosmetics Toxicology, 14(5), 479-480.

- Reifenrath, W. G., & Van Beek, T. A. (2013). Linalool and linalool rich essential oils. In Natural Products (pp. 1541-1587). Springer, Berlin, Heidelberg.

1. Definition Butylphenyl Methylpropional:

Butylphenyl Methylpropional, also known as Lilial, is a synthetic fragrance ingredient commonly used in cosmetics and personal care products. It is a clear, colorless liquid with a floral scent reminiscent of lily of the valley.

2. Use:

Butylphenyl Methylpropional is used as a fragrance ingredient in a wide range of cosmetic products, including perfumes, lotions, creams, and hair care products. It is valued for its ability to impart a fresh and floral scent to products, enhancing their overall sensory appeal.

3. Usage Butylphenyl Methylpropional:

When using products containing Butylphenyl Methylpropional, it is important to be aware of potential sensitivities or allergies to the ingredient. Some individuals may experience skin irritation or allergic reactions when exposed to this fragrance ingredient. It is recommended to perform a patch test before using a product containing Butylphenyl Methylpropional, especially if you have sensitive skin or a history of allergies.

4. References:

- Scientific Committee on Consumer Safety (SCCS). (2018). Opinion on Butylphenyl Methylpropional. Retrieved from https://ec.europa.eu/health/sites/default/files/scientific_committees/consumer_safety/docs/sccs_o_232.pdf

- Cosmetics Info. (n.d.). Butylphenyl Methylpropional. Retrieved from https://cosmeticsinfo.org/ingredient/butylphenyl-methylpropional

- Environmental Working Group (EWG). (n.d.). Butylphenyl Methylpropional. Retrieved from https://www.ewg.org/skindeep/ingredients/702319-BUTYLPHENYL_METHYLPROPIONAL/

1. Definition Alpha Isomethyl Ionone:

Alpha Isomethyl Ionone is a synthetic fragrance ingredient commonly used in cosmetics and personal care products. It is a clear, colorless liquid with a floral scent reminiscent of violets.

2. Use:

Alpha Isomethyl Ionone is primarily used as a fragrance ingredient in a wide range of cosmetic products such as perfumes, lotions, creams, and hair care products. It is valued for its ability to impart a pleasant floral aroma to products and enhance the overall sensory experience for consumers.

3. Usage Alpha Isomethyl Ionone:

When using products containing Alpha Isomethyl Ionone, it is important to be aware of potential skin sensitivities or allergies. Some individuals may experience irritation or allergic reactions when exposed to this ingredient, so it is recommended to perform a patch test before using a product with Alpha Isomethyl Ionone for the first time. Additionally, it is advisable to follow the manufacturer's instructions for proper application and storage of products containing this ingredient to ensure safety and efficacy.

4. References:

- SCCS (Scientific Committee on Consumer Safety). Opinion on Alpha-Isomethyl Ionone. (2013). https://ec.europa.eu/health/scientific_committees/consumer_safety/docs/sccs_o_123.pdf

- CosmeticsInfo.org. Alpha-Isomethyl Ionone. https://www.cosmeticsinfo.org/ingredient/alpha-isomethyl-ionone

- Personal Care Council. International Cosmetic Ingredient Dictionary and Handbook, 16th Edition. (2016).

1. Definition Bht:

Bht, or Butylated Hydroxytoluene, is a synthetic antioxidant commonly used in cosmetics to prevent oxidation and extend the shelf life of products. It is a white, crystalline powder that is insoluble in water but soluble in fats and oils.

2. Use:

Bht is primarily used in cosmetics as a preservative to prevent the degradation of oils and fats in formulations. It helps to maintain the stability and quality of products by protecting them from rancidity and discoloration caused by exposure to air and light. Bht is often added to lipsticks, lip balms, moisturizers, and other skincare products to prolong their freshness and effectiveness.

3. Usage Bht:

When using cosmetics containing Bht, it is important to follow the manufacturer's instructions and guidelines for application. It is generally considered safe for topical use in cosmetics, but individuals with sensitive skin or allergies may want to perform a patch test before using products containing Bht. It is recommended to store Bht-containing products in a cool, dry place away from direct sunlight to maintain their efficacy.

4. References:

- Cosmetic Ingredient Review Expert Panel. (1988). Final report on the safety assessment of BHT. International journal of toxicology, 7(5), 669-735.

- Food and Drug Administration. (2021). CFR - Code of Federal Regulations Title 21. Retrieved from https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=172.110

- National Center for Biotechnology Information. (2021). PubChem Compound Summary for CID 31404, Butylated hydroxytoluene. Retrieved from https://pubchem.ncbi.nlm.nih.gov/compound/Butylated-hydroxytoluene