HC Red No. 1

What Is It?

HC Red No. 1, which refers to Hair Colorant Red No. 1, occurs as a dark brown crystalline material. HC Red No. 1 is used in the formulation of semi-permanent hair dyes, colors and tints.

Why Is It Used?

HC Red No. 1 helps to impart a 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

HC Red No. 1 is used in semi-permanent hair coloring systems that are usually applied in a shampoo base and contain thickeners, alkalizers, and foam stabilizers.

Safety Information

The safety of HC Red No. 1 has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. The CIR Expert Panel reviewed the scientific data and concluded that HC Red No. 1 was safe as used in hair dye formulations at concentrations of 0.5% or less. In 2011, as part of the scheduled re-evaluation of ingredients, the CIR Expert Panel considered available new data on HC Red No. 1 and reaffirmed the above conclusion.

CIR Safety Review:

In a study performed using human cadaver skin, the percutaneous absorption of HC Red No. 1 was poor. Short-term oral feeding of HC Red No. 1 had effects on several organ weights and resulted in liver and splenic lesions. Dermal exposure to almost twice the oral doses produced no evidence of toxicity. In laboratory studies, HC Red No. 1 was not a dermal irritant, but it was a mild ocular irritant. HC Red No. 1 was a contact sensitizer, but not a photosensitizer.

No reproductive or developmental toxicity was observed when a formulation containing 0.15% HC Red No. 1 was applied dermally, and neither fetotoxic nor developmental effects were observed after exposure to 0.1% or less HC Red No. 1. No evidence of mutagenic potential was seen in most assays.

No carcinogenic effects were reported after dermal dosing with HC Red No. 1, but several possible effects were seen in a skin-painting study with 0.15% HC Red No. 1. Whether these effects were compound-related was unclear. A repeated-insult patch test of a 3% slurry of HC Red No. 1 completed on 103 individuals with normal skin produced one possible and one definite sensitization reaction. Because the ingredient is used at a low concentration and very little is actually absorbed, the oral exposure data using concentrations of 0.1% or less represent a much higher exposure than would occur through the skin. The general absence of toxicity in such oral studies supports the safety of use of HC Red No. 1 in hair dye formulations at concentrations of 0.5% or less.

More information about the safety of hair dyes

In the European Union, HC Red No. 1 is permitted for use in non-oxidative hair dye products at concentrations up to 1%. See Annex III for additional information about the use of HC Red No. 1 in hair dye products in Europe.

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.

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. HC Red No. 1 is an aromatic compound also known as 4-amino-2-nitrodiphenylamine. HC Red No. 1 functions as a hair colorant.


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 HC Red No. 1 http://ec.europa.eu/health/ph_risk/committees/04_sccp/docs/sccp_o_072.pdf

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