Hair Straightening Products Have a Dangerous Wrinkle

black woman beautiful straight hair

Do you long for straight hair? Are you a frequent user of hair straightening products? A recent 11-year study found that women who use hair straightening and relaxer products at least four times a year are twice as likely to develop uterine cancer than those who don’t use these products.

About uterine cancer

In 2022, approximately 65,950 women in the United States and 8,100 in Canada will be diagnosed with uterine cancer. Also referred to as endometrium cancer because most cases begin in the endometrium (layer of cells that make up the uterine lining); the risk factors include obesity, age 50 and older, the start of menstruation before age 12, never being pregnant, use of estrogen replacement therapy, late menopause, polycystic ovarian syndrome, and a diet high in animal fat.

Uterine cancer is more common among black women than white women. Deaths from uterine cancer increased by about 1 percent each year between 2015 and 2019, but since then, death rates have stabilized.

Hair straightening product study findings

In this new study, experts evaluated more than 33,000 women ages 35 to 74 over about an 11-year period. A total of 387 cases of uterine cancer were diagnosed during that time. The researchers did not find a relationship between developing uterine cancer and using other hair products, such as bleach, highlights, perms, or hair dyes.

According to the study’s lead author, Alexandra White, Ph.D., head of the NIEHS Environment and Cancer Epidemiology group, they had “estimated that 1.64% of women who never used hair straighteners would go on to develop uterine cancer by the age of 70; but for frequent users, that risk goes up to 4.05%.”

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Although the authors did not find that the incidence of uterine cancer was different by race, it is possible the harmful effects from straightener use may be greater for black women, as about 60 percent of the participants who used the products were black.

Che-Jung Chang, Ph.D., another author of the study, pointed out that because black women tend to begin using straightening products at an earlier age than other races and they use them more often, “these findings may be even more relevant for them.”

Straighteners may be so hazardous because they are easily absorbed through the scalp, and they may be enhanced by lesions and burns the straighteners can cause, as these products contain bisphenol A, formaldehyde, parabens, and metals.

Earlier study’s findings

The findings in this new study align with those reported by some of the same researchers in earlier work. In that study, they reported that using permanent hair dye and chemical hair straighteners could increase women's risk of breast cancer. Black women were at significantly higher risk of breast cancer associated with permanent hair dye: during a mean follow-up of 8.3 years, the breast cancer risk was 45 percent higher among black women and 7 percent among white women.

Bottom line

Using hair straighteners and relaxers is associated with a greater risk of developing uterine cancer, which is already greater among black women. Although the researchers did not document the brand names or ingredients of the products used, chemicals commonly found in these items (bisphenol A, parabens, metals, formaldehyde) may be responsible. This study and previous findings suggest that the use of such hair products poses a significant risk to women.

Canadian Cancer Society. Uterine cancer statistics. 2022 May
Chang CJ et al. Use of straighteners and other hair products and incident uterine cancer. Journal of the National Cancer Institute 2022 Oct 17
National Institutes of Health. Hair straightening chemicals associated with higher uterine cancer risk. NIH news release. 2022 Oct 17
Uterine cancer: statistics. Cancer.Net 2022 Feb
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Lisa Roth Collins is a Registered Holistic Nutritionist (RHN) and is the Marketing Manager at She is passionate about health and wellness and tries her best to make healthier choices every day for herself and her family. Her journey to natural health was driven by her own struggles with digestive discomfort, depression, and anxiety. Lisa returned to school in 2014 to study nutrition at the Canadian School for Natural Nutrition. She threw herself into her studies so she could learn as much as she could to help herself feel better and thrive. Upon completing the program and being certified as an RHN, Lisa began her work at Naturally Savvy where she has been able to help so many people learn to make healthier choices for themselves. Through her work, she has connected with so many incredible people in the industry whether other authors, influencers, or brands. Plus, she is affectionately known as "Techie Spice" because of her ability to wrap her head around technology. Every day she gets up with a renewed sense of energy and ready to make a difference. You can read all of Lisa's content here. In her spare time, Lisa loves to try new recipes, make delicious and nourishing meals, and she is an avid reader. For more information about Lisa, check out her profile on here.