Are Chemical Hair Straightening Products Increasing Women's Risk of Cancer?

A recent study published in the Journal of the National Cancer Institute identified a possible link between the use of hair straightening chemicals (relaxers) with a higher risk of uterine cancer. For some women, including Black women, who use relaxers more often than women of other races and ethnicities, this news raises questions and concerns about the way they style their hair.

Deborah A. Scott, MD, a Mass General Brigham dermatologist, discusses the study’s findings, shares tips for safe alternatives, and explores the industry’s responsibility to develop safer relaxers.

Dr. Scott is director of Diversity, Equity, and Inclusion at Brigham and Women’s Hospital, and director of the Brigham’s Laser and Skin Health Center. She also serves as co-director of the Skin of Color Dermatology Program and the Hair Loss Clinic. Dr. Scott treats patients at the Brigham and Women’s main campus and Brigham and Women’s Fish Center for Women’s Health at 850 Boylston Street.

Linking relaxers to uterine cancer

Uterine cancer is a rare form of cancer. It can be either endometrial cancer (the most common type of uterine cancer) or uterine sarcoma.

Black women have a higher risk of developing endometrial cancer than white women do, and they also have a worse survival rate compared to white women. Most uterine cancers are associated with hormones such as estrogen.

That’s where relaxers may come into play.

Dr. Scott explains, “Certain chemicals may function as endocrine disrupting agents or hormone disruptors. These chemicals may either mimic or block hormones such as estrogen. Chemical straighteners have ingredients, such as phthalates, parabens, and cyclosiloxanes, which function as hormone disruptors. These ingredients may play a role in cancers triggered by hormones, like uterine cancer. Some of the chemicals in fragrances and sunscreens are endocrine disruptors as well.”

It’s important to understand that this association between chemicals in relaxers and uterine cancer is only one of many other risk factors for uterine cancer, including diet and exercise, obesity, type 2 diabetes, and prior estrogen therapy.

Reduce exposure to chemical hair straightening products 

People worried about the potential link between relaxers and uterine cancer don’t have to give up their hairstyles altogether.

“I don’t think everyone should just stop getting relaxers,” says Dr. Scott. If you do choose to use relaxers, there are ways you can help reduce your exposure to these chemicals:

• Protect your scalp. “Anyone who is having any treatment done to their hair should first make sure their scalp is in good health,” says Dr. Scott. “If your scalp is irritated or if you’ve been scratching it, that affects the skin and makes it more porous. When that happens, more chemicals can be absorbed through your scalp. Hairdressers can coat your scalp with a Vaseline type of product before using relaxers to minimize direct contact with the scalp.”
• Seek gentler products. “I encourage people to use products that are hypoallergenic and fragrance free—especially if they’re having problems with their scalp,” Dr. Scott says.
• Minimize exposure to heat. As Dr. Scott explains, “Heat will irritate your scalp. And if you aren’t treating your hair gently and you’re using high heat, you risk hair breaking.”
• Spread out your relaxer treatments. “Try stretching out your relaxers to 2 to 3 times per year, if possible,” says Dr. Scott.

Dr. Scott also suggests that women consider wearing their hair naturally. “More and more Black women are embracing their natural hair, and there are now so many styling options and salons that specialize in natural hair. I always suggest that women consider working with their natural hair as an alternative to straightening with relaxers.”

A call for more research on hair relaxers and cancer

At the end of the study, the authors call for more research to find the specific chemicals driving the link between chemical hair straightening products and uterine cancer. Dr. Scott echoes that call and stresses the importance of industry accountability. 

“Black hair care is a multimillion-dollar industry. Black women spend more money on hair styling products than any other ethnic group and are the primary market for hair relaxers,” she says. “Black women should have safe options for hair styling. It’s not alright to say, ‘Just don’t relax your hair.’ That’s not an adequate answer. There is a responsibility on the part of the hair care industry to develop relaxers that are safe for women with tightly curled hair who choose to wear their hair straight.”