Safety Information

The safety of 2-Amino-6-Chloro-4-Nitrophenol and its hydrochloride salt has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. The CIR Expert Panel evaluated the scientific data and concluded that 2-Amino-6-Chloro-4-Nitrophenol and its hydrochloride salt were safe for use in hair dye formulations at concentrations up to 2.0%.

CIR Safety Review: 2-Amino-6-Chloro-4-Nitrophenol was poorly absorbed through the skin. Less than 0.25% of 2-Amino-6-Chloro-4-Nitrophenol found in a nonoxidative hair dye was absorbed. Less than 0.2% of 2-Amino-6-Chloro-4-Nitrophenol found in an oxidative hair dye was absorbed. In subchronic oral studies, a no observable adverse effect level of 30 mg/kg/day for 2-Amino-6-Chloro-4-Nitrophenol was determined; at higher doses, increased organ weights were seen. A 2% solution of 2-Amino-6-Chloro-4-Nitrophenol applied under occlusive conditions was found to be non-irritating. At 0.1%, 2-Amino-6-Chloro-4- Nitrophenol was nonsensitizing; at 2%, there was sufficient skin coloration from the dye that assessment of sensitization was difficult; but no obviously sensitized areas were reported. An oral developmental toxicity study showed no birth defects. In one genotoxicity test in bacteria, Salmonella strains TA97, TA98, and TA100 showed an increase in mutations, with and without metabolic activation. Strain TA1535 was negative.

In another test in bacteria, Salmonella strains TA97 and TA100 showed no increase in mutations upon treatment with 2-Amino-6-Chloro-4-Nitrophenol, with and without metabolic activation. Strain TA98 was negative with metabolic activation but positive without activation. In follow-up testing with strain TA98-NR, there was no increase in mutations in the absence of activation. Mutagenicity assays in other systems were negative. The poor absorption through the skin, lack of any developmental effect, and negative mutagenesis data in certain bacterial test strains and in other systems suggested that any systemic effects from the use of actual products were unlikely. The CIR Expert Panel concluded that the highest concentration of 2-Amino-6-Chloro-4-Nitrophenol tested (2%) was safe for use in hair dye formulations.

More information about hair dye safety.

2-Amino-6-Chloro-4-Nitrophenol and its salts are listed in the Cosmetics Directive of the European Union (see Annex III) and may be used as oxidizing and non-oxidizing coloring agents for hair dyeing at maximum concentrations of 2% in the finished product, and a maximum concentration of 1% when mixed with hydrogen peroxide. Products containing these ingredients must be labeled as indicated in Annex III.

Link to the EU Cosmetic Regulation: http://europa.eu/legislation_summaries/consumers/product_labelling_and_packaging/co0013_en.htm



What Is It?

2-Amino-6-Chloro-4-Nitrophenol is described as yellow crystals or an orange-yellow, fine-grained powder. 2-Amino-6-Chloro-4-Nitrophenol and its hydrochloride salt (2-Amino-6-Chloro-4- Nitrophenol Hydrochloride) are used in the formulation of semi-permanent and permanent hair dyes, colors, and tints.

Why Is It Used?

2-Amino-6-Chloro-4-Nitrophenol and its hydrochloride salt help to 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

2-Amino-6-Chloro-4-Nitrophenol and its hydrochloride salt are used in semi-permanent hair coloring systems that are usually applied in a shampoo base. These two ingredients are also used in permanent (oxidative) hair dyeing where color is produced inside the hair fiber. The color that is produced results from 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.