Natural hair dyes have been in use, as far as we know, since ancient Egyptian times when cochineal (a type of red beetle) and henna were commonly used. However, only since the 1970s have hair dyes with natural ingredients become a popular alternative in modern hairdressing salons.
Natural hair dyes work in a similar manner to semi-permanent dyes. Pre-developed colour molecules, already present in the natural product, are deposited in the hair. These mask the natural pigments in hair, reflecting and absorbing different light wavelengths in order to create a different colour effect. Usually only the tone of colour can be changed, however some products may have a mild lightening effect. Coverage of grey hair is minimal.
Natural colours usually have an excellent cohesion to keratin, a product found within hair; the pigments penetrate the hair shaft slowly. Hair treated in this way usually has a high sheen due to the astringent effect of these products.
