Safety Information

Expert Panel for Cosmetic Ingredient Safety:

The safety of 4-chlororesorcinol has been assessed by the Expert Panel for Cosmetic Ingredient Safety. The Expert Panel evaluated the scientific data and concluded that 4-chlororesorcinol was safe in hair dye formulations. In 2011, as part of the scheduled re-evaluation of ingredients, the Expert Panel considered available new data on 4-chlororesorcinol and reaffirmed the above conclusion.

The Expert Panel concluded that the scientific data suggested that 4-chlororesorcinol can be safely used in hair dye products. Sub chronic dermal exposure to a hair dye product containing 2% 4-chlororesorcinol produced no evidence of compound-induced toxicity. At the same concentration, no development effects, no evidence of reproductive toxicity, and no carcinogenic effects were seen following dermal exposure. Likewise, 4-chlororesorcinol was not mutagenic in either a micronucleus or in bacteria, nor did it induce aneuploidy in fungus cells. A 2.5% solution was not a dermal irritant or an ocular irritant.

More information about the safety of hair dyes.

4-Chlororesorcinol is permitted for use in oxidative hair dyes in the European Union at a maximum concentration of 2.5%. See Annex III for more information about the use of this ingredient in hair dyes in Europe.



What Is It?

In cosmetics and personal care products, 4-chlororesorcinol is used in the formulation of hair dyes, colors and tints.

Why Is It Used?

4-Chlororesorcinol imparts a color to hair. The exact color obtained will depend on the other ingredients that are used in the hair dye preparation and the starting color of the hair.

Scientific Facts

4-Chlororesorcinol is 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 dye precursors and couplers 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 dye precursors are oxidized by the hydrogen peroxide to form reactive intermediates which then combine with the couplers resulting 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. 4-Chlororesorcinol is a halogenated phenol that functions as a hair colorant in cosmetics and personal care products.