2,4-Diaminophenoxyethanol HCl

Safety Information

The safety of 2,4-Diaminophenoxyethanol HCl and 2,4-Diaminophenoxyethanol Sulfate has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. The CIR Expert Panel evaluated the scientific data and concluded that 2,4-Diaminophenoxyethanol, HCl and 2,4-Diaminophenoxyethanol Sulfate were safe as hair dye ingredients.

CIR Safety Review: No significant adverse changes were observed in a subchronic toxicity test of 2,4-Diaminophenoxyethanol HCl. 2,4-Diaminophenoxyethanol HCl was practically nonirritating to the eyes, and slightly irritating to the skin when tested at a concentration of 4.0%. Based on the available data, 2,4-Diaminophenoxyethanol Dihydrochloride was judged to produce low level sensitization in humans. Developmental studies of 2,4-Diaminophenoxyethanol did not result in any effects. Most genotoxicity assays in bacteria were negative. 2,4-Diaminophenoxyethanol HCl was not active in genotoxicity studies in animals. Based on the results of two studies, 2,4-Diaminophenoxyethanol was not a carcinogen. Although no specific data on the sulfate salt of 2,4-Diaminophenoxyethanol were identified, the CIR Expert Panel determined that the toxicity data on 2,4-Diaminophenoxyethanol HCl could be extrapolated to 2,4-Diaminophenoxyethanol Sulfate. 2,4-Diaminophenoxyethanol and its salts are listed in the Cosmetics Directive of the European Union and may be used as oxidizing coloring agents for hair dyeing at a maximum concentration of 4.0% in the finished product, or when used in combination with hydrogen peroxide, a maximum use concentration upon application of 2.0% (see Annex III). 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

More information about the safety of hair dyes.

Resources

The FDA's factsheet on Hair Dye Products
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Search the FDA Code of Federal Regulations
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The European Commission's Scientific Committee on Consumer Products (SCCP) Opinion
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EU Cosmetic Ingredients Inventory
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2,4-Diaminophenoxyethanol HCl


Chemical image provided by National Cancer Institute
What Is It?

2,4-Diaminophenoxyethanol HCl occurs as a light gray to a light pink powder. 2,4-Diaminophenoxyethanol Sulfate is a white powder. In cosmetics and personal care products, 2,4-Diaminophenoxyethanol HCl and 2,4-Diaminophenoxyethanol Sulfate are used in the formulation of permanent hair dyes, colors, and tints.

Why Is It Used?

2,4-Diaminophenoxyethanol HCl and 2,4-Diaminophenoxyethanol Sulfate 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

2,4-Diaminophenoxyethanol HCl and 2,4-Diaminophenoxyethanol Sulfate 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.

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. 2,4-Diaminophenoxyethanol HCl and 2,4-Diaminophenoxyethanol Sulfate are aromatic amines. In cosmetics and personal care products, 2,4-Diaminophenoxyethanol HCl and 2,4-Diaminophenoxyethanol Sulfate function as hair colorants.