What Is It?

p-Aminophenol is an off-white crystalline solid. m- and o-Aminophenol occur as an off-white to gray-green solid, and a white to tan crystalline solid, respectively. In cosmetics and personal care products, p-, m- and o-Aminophenol are used in the formulation of permanent hair dyes, colors and tints.

Why Is It Used?

p-, m- and o-Aminophenols 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

p-Aminophenol, m-Aminophenol and o-Aminophenol 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.

Safety Information

The safety of the Aminophenol hair colorants has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. The CIR Expert Panel evaluated the scientific data and concluded that p-, m-, and o-Aminophenols were safe for use as hair dyes. In 2005, the CIR Expert Panel considered available new data on p-, m- and o-Aminophenol and reaffirmed the above conclusion.

CIR Safety Review:

The CIR Expert Panel reviewed the Aminophenols as ingredients of hair dye products. The CIR Expert Panel acknowledged that p-, m-, and o-Aminophenol are metabolized by pathways similar to those for acetaminophen. When levels of glutathione (a compound that bind to other compounds usually resulting in a decease in toxicity) in the body are low, acetaminophen and the aminophenols can be metablized ito genotoxic compounds. The formation of these genotoxic compounds can occur in in vitro genotoxicity assays. The CIR Expert Panel recognized that the in vitro mutagenicity tests used to screen the Aminophenols failed to model the in vivo situation and therefore, they considered that the mutagenic potential of the Aminophenols demonstrated in the in vitro tests were not relevant to the use of these materials in hair dye products. This conclusion was supported by the failure of hair dye products containing p-, m- and o-Aminophenols to induce cancer when applied topically.

More information about the safety of hair dyes

In Europe, m-Aminophenol and o-Aminophenol and their salts are listed in Annex III, Part 2 (list of substances provisionally allowed) and may be used in oxidizing coloring agents at a maximum concentration of 2%, or when used in combination with hydrogen peroxide, at a maximum concentration of 1%. Products containing m-Aminophenol and o-Aminophenol 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

More Scientific Information

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.


The FDA’s factsheet on Hair Dye Products http://www.fda.gov/Cosmetics/ProductandIngredientSafety/ProductInformati…

Search the FDA Code of Federal Regulations http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm

The European Commission’s Scientific Committee on Consumer Products (SCCP) opinion on para-Aminophenol http://ec.europa.eu/health/ph_risk/committees/04_sccp/docs/sccp_o_00e.pdf

EU Cosmetics Inventory http://ec.europa.eu/consumers/cosmetics/cosing/