2-Methylresorcinol

Safety Information

Expert Panel for Cosmetic Ingredient Safety:

The Food and Drug Administration (FDA) permits resorcinol to be used in topical acne Over-The-Counter (OTC) drug products at concentrations of up to 2% when used in combination with sulfur at levels of 3-8%. Resorcinol is also permitted as active an ingredient in OTC topical analgesics and anorectal drugs. The safety of 2-methylresorcinol and resorcinol has been assessed by the Expert Panel for Cosmetic Ingredient Safety.

The Expert Panel evaluated the scientific data and concluded that 2-methylresorcinol and resorcinol were safe as cosmetic ingredients. In 2006, the Expert Panel considered available new data on 2-methylresorcinol and resorcinol and reaffirmed the above conclusion.

The Expert Panel reviewed data that showed no effects following long term dermal exposure to resorcinol and 2-methylresorcinol. Data indicated that resorcinol and 2-methylresorcinol were mild skin irritants and rare sensitizers. However, at the concentrations used in cosmetics and personal care products, these ingredients were not irritating, sensitizing, or photosensitizing when tested on human volunteers. Tests of these ingredients for mutagenicity and carcinogenicity were negative.

FDA: Link to Code of Federal Regulations and Federal Register for Resorcinol

More information about the safety of hair dyes.

Resorcinol is listed in Annex III (substance which cosmetic products must not contain except subject to the restrictions and conditions laid down) and may be used as an oxidizing coloring agent for hair dyeing at maximum concentrations of 1.25%, and in hair lotions and shampoos at a maximum concentration of 0.5%. Products containing resorcinol must be labeled “Contains resorcinol”. 2-methylresorcinol is also listed in Annex III of the Cosmetics Directive of the European Union and may be used in oxidizing and non-oxidizing hair dye products at a maximum concentration of 1.8%.

The Joint FAO/WHO Expert Committee on Food Additives concluded that there is no safety concern at current levels of intake of resorcinol when used as a flavoring agent.

Resources

The FDA's factsheet on Hair Dye Products
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Search the Code of Federal Regulations
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The European Commission's Scientific Committee on Consumer Products (SCCP) Opinion
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EU Cosmetics Inventory
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2-Methylresorcinol


Chemical image provided by National Cancer Institute
What Is It?

Resorcinol is a white crystalline solid with a sweet taste. 2-methylresorcinol is a slightly yellow crystalline powder. In cosmetics and personal care products, both resorcinol and 2-methylresorcinol are typically used in the formulation of hair dyes and colors. Resorcinol is also used in other hair and skin care products.

Why Is It Used?

Resorcinol and 2-methylresorcinol help impart color to hair. The exact color obtained will depend on the other ingredients that are used in the preparation and the starting color of the hair. These ingredients may also function as antioxidants.

Scientific Facts

Resorcinol and 2-methylresorcinol are used in permanent hair coloring systems where color is produced inside the hair fiber. This is accomplished through careful formulation of the product so that the ingredients interact in a highly controlled process. Resorcinol is used for its antiseptic and keratolytic action in acne therapy and for other skin conditions. Resorcinol has been found in roasted barley, in cane molasses, in coffee and in cigarette smoke.

Resorcinol and 2-methylresorcinol function as hair colorants and antioxidants. Resorcinol is also used as an anti-acne agent in OTC drug products. Hair dyeing formulations belong to three categories — temporary, semi-permanent and permanent coloring of hair.

The permanent hair dyeing formulations are often referred to as oxidative hair dyes which are generally marketed as two-component products. One component contains the compounds (precursors including Resorcinol and 2-methylresorcinol) that become the colorants and the other component is a stabilized solution of hydrogen peroxide. The two components are mixed immediately prior to use.

The precursors and peroxide diffuse into the hair shaft, where color formation takes place after the ingredients combine to produce the coloring mixture. The precursors are oxidized by the hydrogen peroxide to form the colorant molecules. These molecules are too large to escape from the hair structure. The hydrogen peroxide in the oxidative hair dye product also serves as bleaching agent for the natural pigment of the hair.

The color that is formed depends on the precursors and direct dyes present in the dyeing solution, pH of the dyeing solution and the time of contact of the dyeing solution with the hair.