product name:


cas No. :


MF :


MW :


Taian, China

9/F,E-commerce Industrial Park

+86 156 6659 0861

Mon to Fri 8am to 6 pm

Send us your inquiry anytime!


Quick Details










Phenol, 5-amino-2-methyl (9CI);


Molecular structure:






Off-white crystalline powder





Melting point
















The results conforms with enterprise standards



5-Amino-O-cresol is mainly used in organic synthesis, dyes, hair dyes and pharmaceutical intermediates.


5-Amino-o-cresol is used almost exclusively in the cosmetic industry as a coupler (secondary intermediate) in oxidative (permanent) hair dye formulations, which produce hair coloration that lasts until the hair grows out. Color is formed inside the hair by hydrogen peroxide-induced coupling reactions of colorless dye precursors. Color-forming reactions are accomplished by primary intermediates, secondary intermediates, and oxidants. The amounts and chemical structures of these precursors, as well as the pH at which the process takes place and the dyeing time, determine the resultant color. The primary intermediates include the so-called para dyes, p-phenylenediamine, p-toluenediamine, p-aminodiphenylamine, and p-aminophenol, which form a quinone monoimine or diimine upon oxidation. The secondary intermediates, or couplers, include m-diamines, m-aminophenols (including 5-amino-o-cresol), polyhydroxyphenols, and naphthols. For example, the reaction of 5-amino-o-cresol with p-phenylenediamine produces a red-violet color; its reaction with p-aminophenol produces an orange-red color. The color of a mixture cannot readily be predicted and involves trial and error. The colorant formulation is mixed with an oxidizing agent (developer) just before application. The preferred developer is usually a 6% solution of hydrogen peroxide, which also bleaches the hair, allowing the development of lighter colors.


Hair dyes are roughly divided into four categories according to the timeliness of dyeing hair: temporary, semi-permanent, permanent and progressive hair dyes.

Temporary hair dyes usually consist of water-soluble acid dyes and water-soluble pigments. Due to the large particles, they cannot enter the hair shaft through the surface of the hair, and only adhere to the surface of the hair shaft to form a colored covering layer. The interaction between hair dye and hair is not strong, and it is easy to be washed away by shampoo.

The effective ingredients of semi-permanent hair dyes are small-molecule synthetic dyes (ie direct dyes), mostly containing nitroaniline derivatives (nitrophenylenediamine and nitroaminophenol), which can penetrate into the hair shaft cuticle and deeper medulla Layer, but the swelling rate is not enough, it does not combine with the natural pigments of the hair, and has little damage to the hair. In addition to a large number of chemically synthesized dye compounds, a variety of natural pigment dyes have also been discovered in recent years for hair dyeing. Henna is one of them. Henna is a brown to reddish-brown dye extracted from the leaves of the Lawsonia plant originally grown in North America and Asia. The US Food and Drug Administration only allows it to be used as a hair dye and not on the skin.

The mode of action of permanent oxidative hair dye is to dye the hair after the dye precursor is oxidized to produce the final dye product. The active ingredients are amine or phenolic compounds, which basically do not fade after dyeing, and the effect is the best. However, due to the growth of the hair, it is usually re-dyed every six weeks. Oxidative hair dyes are the main products in the hair dye market.

Progressive hair dye is based on lead acetate or silver nitrate as the main active ingredient of the dye. It gradually darkens the hair color by interacting with the mercapto group in hair keratin and oxidizing the surface of the hair shaft. Lead acetate is an approved hair dye additive, but the lead content must not exceed 0.6% (mass volume fraction).

Main ingredients

At present, the common hair dyes on the market are permanent hair dyes, and the dyes used include natural plant dyes, metal salt dyes and oxidation dyes. Among them, the most commonly used are oxidation dyes. This type of product is mainly in two-part form. One is a dye-containing matrix, which can be cream, powder or liquid, and the main dye is phenylenediamine; the other is an oxidant, and the main component is hydrogen peroxide. As an aqueous solution, it can also be formulated into a paste-like base or powder. When using, combine the two doses in equal amounts, and then apply them evenly on the hair. After 20-30 minutes of coloring, rinse off with water.

The hair dyeing mechanism of permanent hair dye is simply: the ammonia or alkaline ingredients contained in the hair dye open the scale layer of the hair, and the small dye molecules (intermediate and coupling agent or modifier) penetrate the hair together with the oxidant. In the cortex layer, an oxidative condensation reaction occurs at the same time, and the small dye molecules are oxidized into macromolecular compounds, which remain in the cortex layer to show the target color.




Store in a dry, well-ventilated place away from direct sunlight.


Related products