Tests conducted in China on many brands of shampoo claiming to make people's hair black have shown that these so-called shampoos are actually hair dyes and they contain harmful chemicals such as phenylenediamine.
Local media reports that the shampoos tested were all from Xingfa Square shopping area in Guangzhou, which is reputed to be the largest cosmetics wholesale market in China. All of these shampoos claim to be purely herbal and not harmful to people's health, but a spot test of five samples, including Shouling Yi Xi Hei, Zang Wang Yi Xi Hei, Gexiuyugao Zi Ran Hei, Wendameiyuanshenqi Yi Xi Hei, and Shou Bang Yi Xi Hei, found that all of them contain phenylenediamine, a dye that can cause cancer.
Experts said that although the phenylenediamine content in the shampoos fell into the approved range of 1.1%-1.4%, it can still do harm to people's health if the shampoos are used frequently.
In addition to phenylenediamine another harmful chemical, diaminobenzene, was also found in all of the shampoos listed above, with the exception of Gexiuyugao Zi Ran Hei.