INCI of cosmetics, you know what you are applying on skin Part 17, hair dyes
Today we learn to read INCI of hair dyes in order to recognize the substances that should be avoided and that can cause irritations, dermatitis or can result even carcinogenic.
INCI of cosmetics is the label that, by law in several Countries, has to report the ingredients used in a cosmetic product. Understanding INCI isn’t easy, but it is very useful to recognize the substances that are beneficial to our beauty and other that, on the contrary, irritant or even carcinogenic, should be avoided. Today we’ll try to understand how to choose a good hair dye able to respect our health and the health of hair.
Hair dyes and INCI
It is estimated that hair dyes are used by more than one-third of women aged 18 and over and by about 10% of men above the age of 40. Because of this great use it is important to know what is contained in these products and how to choose the best hair dyes that are also safe for health. In fact, more than 5000 chemical substances can be used in these products and some ingredients may be allergenic or even carcinogenic agents. Fortunately, nowadays the riskiest and carcinogenic substances, such as aromatic amines, are banned. However, some substances to avoid are still present. For example, be careful if in the INCI of your hair dye appear resorcinol, m-aminophenol, p-aminophenol and toluene-2,5-diamine, substances frequently used but considered allergenic and a possible cause of dermatitis of the scalp (Hamann et al, Contact Dermatitis, Apr 2014). Another substance you have to be careful of in the permanent hair dye is p-Phenylenediamine (PPD). This substance may be the cause indeed of dermatitis and, according to scientific studies, it is also considered genotoxic, this means that it may damage DNA and induce tumors (Bolt et al, Crit Rev Toxicol, 2007 – Zhang et al, Al J Epidemiol, Jun 2008). The role of PPD is still debated because there are conflicting studies but, in any case, because there is the risk of a possible carcinogenic effect, a good choice may be to avoid hair dyes that include this ingredient. Hair dyes for black and dark brown hair contain the highest quantities of PPD. Finally, when we speak about permanent hair dye, we must speak also about ammonia, ammonium hydroxide in INCI. Ammonia has the role to modify the pH of the hair in order to open the scales of cuticles and to let the color penetrate. Ammonia is volatile and can cause strong irritations to mucosa in addition to damaging the hair (Dreisbach, Handbook of Poisoning., 1987). Because of these considerations, nowadays it is possible to find easily hair dyes without ammonium hydroxide that is, though, replaced by another substance, monoethanolamine (MEA). However, even this substance isn’t harmless, it is indeed irritant to the mucosa and skin and, according to scientific studies, it is also more aggressive on hair than ammonium hydroxide (Naima et al, ACS Omega, Oct 2018 – Knaak et al, Rev Environ Contam Toxicol 1, 1997). Finally, be careful to other substances that may be present in hair dyes and that can damage the hair such as silicones, you can find for example dimethicone, or mineral oils such as paraffin. Clearly, given these considerations, we can understand that it isn’t easy to choose a good hair dye because irritating substances may be replaced with other substances still aggressive. However, there are natural hair dyes that don’t use chemical substances or in a very limited quantity. The disadvantage is that these products don’t offer a wide range of colors, are less resistant and don’t cover the white hair in a very efficient way, they remain in fact a bit clearer in respect than the other hair, but this type of hair dyes aren’t dangerous for health and this may be a good compromise in order to change hair color but with a respectful product.