Hair Dye Doesn’t Have a Significant Effect on Cancer Risk

Regular hair coloring has no significant effect on cancer risk or mortality—with a few exceptions—according to the largest prospective study on this topic to date. The project, which included 17,200 women and spanned over 36 years, was led by the Medical University of Vienna. The study was published in the British Medical Journal.

While the International Agency for Research on Cancer has classified occupational exposure (e.g. hairdressers) to hair dyes as a probable human carcinogen, personal use of hair dyes had not been classified as such.

Although the research team found no link between personal use of permanent hair dye and the risk of most cancers or cancer-related mortality, it did find a positive association for the risk of basal cell carcinoma, hormone receptor-negative breast cancer (ER-, PR- and ER-/PR-), and ovarian cancer. 

Their findings also include evidence for heterogeneity due to natural hair color: an increased risk of Hodgkin's lymphoma was only observed in women with naturally dark hair, and a higher risk of basal cell carcinoma was especially observed in women with naturally light hair.

"The present prospective cohort study offers some reassurance against concerns that personal use of permanent hair dyes may be associated with an increased risk of cancer or mortality. Nevertheless, we also found a positive correlation for the risk of some cancers," says study leader Eva Schernhammer.  

"Our results justify further prospective validation," explains Schernhammer. "This depends on different populations and countries, different susceptibility genotypes (e.g. NAT1 or NAT2), cancers if different genotypes and molecular genetic phenotypes, different exposure settings (personal use vs. occupational exposure), different time points and different colors of the permanent hair dyes used (dark dyed vs. light dyed), with refined exposure estimates and should be interpreted in the light of the totality of the evidence," she concludes.