Chemical Hair Relaxers May Increase Risk of Uterine Cancer Among Black Women

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Researchers have found that long-term use of chemical hair relaxers may be associated with an increased risk of uterine cancer in postmenopausal Black women, according to a recent study published by Bertrand et al in Environmental Research.


Chemical hair relaxers are heavily marketed to and commonly used by Black individuals to straighten curly or tightly coiled hair. However, the products are loosely regulated and are known to contain potentially harmful chemicals such as endocrine disruptors—which can be absorbed via inhalation or through the skin. Previous studies have linked these chemicals to a wide range of reproductive health outcomes in female patients.

“Black women are often underrepresented in health research and may have unique exposures that contribute to disparities in disease. This study fills an important gap in knowledge about the potential health effects of hair relaxer use, which is very common in Black women,” explained lead study author Kimberly Bertrand, ScD, Associate Professor of Medicine at the Chobanian & Avedisian School of Medicine and an epidemiologist at the Slone Epidemiology Center at Boston University.

Study Methods and Results

In the new study, the researchers asked about 45,000 women who had no prior history of cancer, had an intact uterus, and participated in the Black Women’s Health Study about their past use of chemical hair relaxers. The researchers then followed the women for up to 22 years and compared the rates of uterine cancer among those who reported frequent or long-term use of chemical hair relaxers to those who never or rarely used the products.

Compared with those who never or rarely used chemical hair relaxers, women who reported using hair relaxers more than twice per year or for more than 5 years had more than a 50% increased risk of uterine cancer—even after adjusting for other potential risk factors.


“Our study suggests that moderate and heavy use of chemical hair relaxers may be associated with [a] higher risk of uterine cancer among postmenopausal Black women. In addition, there are major racial disparities in uterine cancer. Compared [with] non-Hispanic [White women], Black women have higher rates of aggressive subtypes of uterine cancer and are nearly twice as likely to die from their disease,” stressed Dr. Bertrand.

The new findings highlighted the importance of continued research regarding the potential adverse health effects of exposure to chemical hair relaxers and their constituents.

The researchers hope these results of their study will raise awareness of the potential adverse effects of these products and promote efforts to reduce exposure.

“Importantly, identification of safer alternatives to straightening hair, stricter regulation of cosmetic products, and policies to prohibit discrimination against natural hair such as the CROWN Act could represent important steps toward reducing racial disparities in uterine cancer,” Dr. Bertrand concluded.

Disclosure: The research in this study was supported by the National Institutes of Health and in part by the Karin Grunebaum Cancer Research Foundation. For full disclosures of the study authors, visit

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.