Safety Information

Expert Panel for Cosmetic Ingredient Safety:

The safety of these six ingredients has been assessed by the Expert Panel for Cosmetic Ingredient Safety. The Expert Panel evaluated the scientific data and concluded that 6-amino-m-cresol, 4-amino-m-cresol, 5-amino-4-chloro-o-cresol, and 5-amino-6-chloro-o-cresol were safe as used in oxidative and nonoxidative (semipermanent) hair dyes. The available data also supported the safety of 6-amino-o-cresol and 4-chloro-2-aminophenol for use in oxidative hair dyes but were insufficient to determine the safety of 6-amino-o-cresol and 4-chloro-2-aminophenol in nonoxidative (semipermanent) hair dyes.

To supplement the safety test data on these ingredients, available data on related ingredients (4-amino-2-hydroxytoluene and p-, m-, and o-aminophenol) previously found safe as used by the Expert Panel were summarized. Percutaneous penetration of 5-amino-4-chloro-o-cresol and 5-amino-6-chloro-o-cresol alone was significant, but when combined with oxidative developer, skin absorption was extremely low. Both of these dyes were excreted rapidly via the urine. Repeated exposure of skin to 5-amino-4-chloro-o-cresol and 5-amino-6-chloro-o-cresol failed to produce any cumulative irritation and single exposures up to 10% were not irritating to skin. 5-Amino-4-chloro-o-cresol and 5-amino-6-chloro-o-cresol combined with oxidizer were not sensitizers in maximization tests. Ocular irritation resulted from exposure to undiluted 5-amino-4-chloro-o-cresol, but not from exposure to a 5% solution. Only minor irritation was observed with 5% 5-amino-6-chloro-o-cresol. Sub chronic toxicity testing using 5-amino-4-chloro-o-cresol, 5-amino-6-chloro-o-cresol and 4-amino-m-cresol did not yield any adverse reactions. 6-Amino-m-cresol and 4-amino-m-cresol were not mutagenic in tests. Exposure to 5-amino-4-chloro-o-cresol, 5-amino-6-chloro-o-cresol, 6-amino-m-cresol and 4-amino-m-cresol from hair dye products were several orders of magnitude below developmental toxicity no-observed-adverse-effect levels (NOAELs).

The available test data, coupled with patch test instructions, supports the safety of these ingredients in oxidative hair dyes. However, all of the data necessary to complete the review of 6-amino-o-cresol and 4-chloro-2-aminophenol in semipermanent hair dyes was not available. The Expert Panel was especially interested in more data on the metabolism of these ingredients. If metabolism was found to be similar to previously reviewed ingredients, additional data would not be necessary.

More information about the safety of hair dyes.

4-Amino-m-cresol and its salts are listed in the Cosmetics Directive of the European Union (see Annex III) and may be used as oxidizing coloring agents for hair dyeing at a maximum concentration of 3.0%, and a maximum concentration of 1.5% when mixed with hydrogen peroxide. 6-Amino-o-cresol and its salts are, and 4-chloro-2-aminophenol are not permitted for use in hair dye products marketed in Europe (see Annex II). 6-Amino-m-cresol, 5-amino-4-chloro-o-cresol and 5-amino-6-chloro-o-cresol are not specifically listed in the Cosmetics Directive.



What Is It?

6-Amino-m-cresol, 6-amino-o-cresol, 4-amino-m-cresol, 5-amino-4-chloro-o-cresol, 5-amino-6-chloro-o-cresol and 4-chloro-2-aminophenol are crystals that range in color from beige and reddish-brown to brown. These ingredients are used in the formulation of semi-permanent and permanent hair dyes, colors, and tints.

Why Is It Used?

6-Amino-m-cresol, 6-amino-o-cresol, 4-amino-m-cresol, 5-amino-4-chloro-o-cresol, 5-amino-6-chloro-o-cresol and 4-chloro-2-Aminophenol 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.

Scientific Facts

6-Amino-m-cresol, 6-amino-o-cresol, 4-amino-m-cresol, 5-amino-4-chloro-o-cresol, 5-amino-6-chloro-o-cresol and 4-chloro-2-aminophenol are primarily 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.

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) 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. 6-Amino-m-cresol, 6-amino-o-cresol, 4-amino-m-cresol, 5-amino-4-chloro-o-cresol, 5-amino-6-chloro-o-cresol and 4-chloro-2-aminophenol are all substituted aromatic compounds. In cosmetics and personal care products, these ingredients function as hair colorants.