Safety Information

Expert Panel for Cosmetic Ingredient Safety:

The safety of these 2-nitro-p-phenylenediamin and 4-nitro-o-phenylenediamine has been assessed by the Expert Panel for Cosmetic Ingredient Safety. The Expert Panel evaluated the scientific data and concluded that for persons not sensitized to these ingredients, 2-nitro-p-phenylenediamine and 4-nitro-o-phenylenediamine were safe as hair dye ingredients. In 2003, as part of the scheduled re-evaluation of ingredients, the Expert Panel considered available new data on 2-nitro-p-phenylenediamine and 4-nitro-o-phenylenediamine and reaffirmed the above conclusion.

Experimental data on 2-nitro-p-phenylenediamine and 4-nitro-o-phenylenediamine, and hair dyes containing these ingredients, suggest that both compounds were nonirritating to the skin and eyes, but were sensitizers on skin. The results of repeated insult patch tests with hair dye products containing these ingredients indicated that neither was an irritant nor a sensitizer to human subjects as normally used.

In the absence of human data on the pure compounds, however, 2-nitro-p-phenylenediamine and 4-nitro-o-phenylenediamine were considered to be potential human sensitizers. Both ingredients, when topically applied, were absorbed. Neither embryotoxicity nor developmental effects were observed when hair dyes containing 2-nitro-p-phenylenediamine and 4-nitro-o-phenylenediamine were applied to the skin. Both ingredients were mutagenic in some bacterial and in vitro systems; both compounds had some genotoxic activity. In feeding studies, very large doses of 2-nitro-p-phenylenediamine induced hepatocellular tumors in female mice. Both compounds were noncarcinogenic in male mice, and in both sexes of rats.

More information about the safety of hair dyes.

2-Nitro-p-phenylenediamine and its salts are not permitted for use in hair dyes in the European Union (see Annex II). 4-Nitro-o-phenylenediamine may be used in oxidative hair marketed in Europe according at a maximum concentration of 0.5%. See Annex III for more information about the use of 4-nitro-o-phenylenediamine in hair dye products.

The European Commission’s Scientific Committee on Consumer Products (SCCP) reviewed the safety of 4-nitro-o-phenylenediamine and concluded that with the exception of sensitizing potential, it did not pose a risk to the consumer when used in hair dyes at concentrations less than or equal to 0.5%.



What Is It?

2-Nitro-p-phenylenediamine is a reddish-brown crystalline powder. 4-Nitro-o-phenylenediamine is a red powder. In cosmetics and personal care products, these two ingredients are used in the formulation of semi-permanent and permanent hair dyes, colors and tints.

Why Is It Used?

2-Nitro-p-phenylenediamine and 4-Nitro-o-phenylenediamine 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.

Scientific Facts

2-Nitro-p-phenylenediamine and 4-nitro-o-phenylenediamine are used in semi-permanent hair coloring systems that are usually applied in a shampoo base and contain thickeners, alkalizers, and foam stabilizers. 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. Temporary coloring preparations, often called color rinses, provide color which lasts until the first shampooing. Ingredients which impart temporary color may have a fairly high molecular weight and are unable to penetrate the hair shaft. These materials are simply deposited onto the hair fiber and are removed by subsequent shampooing. Semi-permanent coloring preparations generally provide color through several shampooings. These materials are often low molecular weight pre-formed dyes which can penetrate the hair shaft to some extent.