HAIR RELAXER STUDIES

October 2022: Uterine cancer

National Institutes of Health finding: Regular hair relaxer users were more than twice as likely to develop uterine cancer as women who did not use the product. The researchers estimated that 4% of frequent users of hair straighteners would develop uterine cancer by age 70; for nonusers, the risk was 1.6%, according to the Journal of the National Cancer Institute.

July 2021: Breast cancer

Carcinogenesis finding: Researchers found no clear evidence that hair relaxer use was associated with breast cancer risk for most women. But heavy users of lye-containing products — at least seven times a year for 15 years or more — had an increased risk of breast cancer. Results of the few previous studies on this topic are inconsistent, the researchers said. One, a May 2021 study, found use of perms and straighteners during adolescence may be associated with a higher risk of premenopausal breast cancer.

January 2012: Fibroids (uterine leiomyomata)

American Journal of Epidemiology finding: Among premenopausal Black women, researchers observed increased risks of fibroids in association with use of hair relaxers. The researchers said these findings “raise the hypothesis that hair relaxer use increases uterine leiomyomata risk.”

Note: All of these findings come from two major long-term data sets: the “Black Women’s Health Study,” which has been tracking tens of thousands of women since 1995, and the “Sister Study,” a breast cancer study that has been tracking tens of thousands of women since 2003.