The most common synthetic colors used in cosmetics and hair dyes are called FD&C colors and they are derived from coal tar, which in turn is a by-product of petroleum. Because some coal tar dyes have been known to cause cancer, they are are regulated by the FDA as to the amount of lead or arsenic they contain, limiting these elements to 10 parts per million. In the USA, the following artificial colorings are permitted by the FDA:
FD&C Blue No. 1 (Brilliant Blue FCF, E133), Approved for external use in soaps and lotions and Blue No.4. FD&C Black No.2 and No.3. FD&C Brown No.1. FD&C Green No. 3 (Fast Green FCF, E143 not to be used for eyes, lips, mucous membranes, and Green 5 ,6 and 8). FD&C Orange No. 4, 5, 10 and 11. FD&C Red 4, 6, 7, 17, 21, 22, 27, 28, 30, 31, 33, 34, 36, FD&C Red No. 40 (Allura Red AC, E129). FD&C Violet No.2. FD&C Yellow No. 5 (Tartrazine, E102). FD&C Yellow No. 6 (Sunset Yellow FCF, E110) and F&G Yellow No: 7, 8, 10, 11.
Although I found a 1984 study on mice that concluded that coal tar dyes were not toxic, there has been recent evidence suggesting that they are potentially carcinogenic. “Women using permanent hair dye at least once a month for a period more than one year more than double their risk of bladder cancer” (USC School of Medicine, Gago-Dominguez et al. 2001). This paper also stated that women who are genetically vulnerable to bladder cancer (so-called “slow acetylators” who are exposed to some carcinogens for longer periods of time) using permanent hair dye at least once a month for a period of 10 years or more had more than 4 times more risk for bladder cancer.
Coal tar dyes associated with cancer include 4-methoxy-m-phenylenediamine (which we spotted in the Naturtint hair color the other day), 2,4-diaminoanisole, 4-chloro-m-phenylenediamine, 2,4-toluenediamine, 2-nitro-p-phenylenediamine, 4-amino-2-nitrophenol.
The term lake dyes refers to water insoluble colors. Lake colors can also be derived from coal tar and can trigger allergic reactions. Studies have shown brilliant lake red R to be one of the worst offenders. It should be noted that coal tar is also used as a dandruff therapy in shampoos.
In addition to coal tar, cosmetic colors can also be made from chromium oxide and aluminum powder. Chromium oxide is usually called chrome green and the Material Safety Data Sheet describes it as a “cancer hazard”. It is used in Sephora’s Pure range. Aluminum powder is an irritant.
Some synthetic lake colors seem to be perfectly safe. For example, disperse black 9 (used in the Surya Henna hair dye) has been deemed by researchers to be safe. HC yellow 2 is regarded as a low hazard by the EWG and the Cosmetic Ingredients Review (an industry body) says it is safe at concentrations up to 3%. Surya Henna also has HC Yellow 4, although this broadly seems to be safe, apart from concerns about reproductive toxicity that have led the CIR to impose a limitation on dose of 3%. Incidently, Surya lists HR red 3, about which I haven’t been able to find any information.
Safe colors are made from mica flakes and iron oxides – see, for example, RMS Beauty Lip2Cheek. The latter are graded safe for cosmetic use as they are produced synthetically in order to avoid the inclusion of ferrous or ferric oxides, and impurities normally found in naturally occurring iron oxides.
Other pigments and dyes, such as beet powder, come from plants. Makeup brands such as 100% Pureuse only plant-derived pigments. The only one to avoid is carmine, a crimson pigment made from the ground-up, dried bodies of a cacti-eating bug called the cochineal insect. As well as not being appealing to strict vegans, carmine is an irritant.