Can Hair Relaxers and Straighteners Cause Uterine Cancer?

Written by: Rob Levy
Medically Reviewed By: Ursula A. Matulonis, MD

Key Takeaways:

• A 10-year study finds women who often use straighteners have higher risk of uterine cancer than those who have never used them, though more research is needed.
• The increased risk may especially pertain to Black women, though the reason why is unclear. 60% of study participants who said they use hair straighteners identified as Black women.
• Women concerned about the relation between straighteners and uterine cancer risk can take a number of steps to reduce their chance of developing the disease.

A recent study found that women who frequently use chemical hair straighteners and relaxers could have a higher risk of developing uterine cancer than those who have not used the products. The study, which tracked 34,000 women nationwide for more than a decade, comes at a time when uterine cancer rates in women are increasing, especially among Black women.

The researchers found that women in the study who never used hair straighteners had a 1.64% risk of developing uterine cancer by age 70 compared to a 4.05% risk for those who often use straighteners. Frequent use was defined as four times in the previous year, regardless of whether women applied the products themselves or had them applied by others.

The increased risk was found in women of all racial and ethnic backgrounds, but it might be more pronounced among Black women: 60% of participants who said they used hair straighteners identified as Black women.

Although the authors of the new study didn’t track the brands of hair straighteners used by participants, they noted that several chemicals found in such products — bisphenol A, formaldehyde, metals, parabens, and others — may contribute to increased cancer risk.

The study didn’t explore how the chemicals in straighteners might lead to uterine cancer, but it is the first epidemiological study to show an association between straighteners and the disease. The study authors stated that more research would be needed to strengthen the link. Previous studies have tied the use of hair straighteners to ovarian and breast cancers, which, like uterine cancer, tend to be hormonally driven.

Women concerned about the relation between straighteners and uterine cancer risk can take a number of steps to reduce their chance of developing the disease, doctors say. One option is to reduce one’s use of such products — cutting back from four times a year to two or three, for example. Increasing physical activity may also help. 

About uterine cancer

The most common form of uterine cancer, called endometrial cancer, forms in the lining of the uterus and is the most common cancer of the female reproductive system. According to the American Cancer Society, nearly 66,000 new cases of cancer of the uterus will be diagnosed this year and about 12,550 women will die of the disease. (The estimates include endometrial cancers as well as uterine sarcomas, which begin in the muscle and supporting tissues of the uterus and account for about 10% of all uterine cancers.)

Endometrial cancer usually occurs after menopause. The average age at diagnosis is about 60 years.

While the overall rates of uterine cancer have been rising among women in the U.S., Black women die of the disease at twice the rate of white women, research has shown.

“Black women have a higher risk of developing endometrial cancer and also have a worse survival rate compared to white women,” says Ursula Matulonis, MD, chief of the Division of Gynecologic Oncology at Dana-Farber. “It hasn’t been fully explained why that’s happening, but it’s definitely being observed.”

There is currently no screening test for uterine cancer, and it’s important for women to know the symptoms of the disease, she adds. The most common symptom is post-menopausal bleeding and spotting for women who are still menstruating. “It’s heavier bleeding or bleeding between periods,” Matulonis says.

About the Medical Reviewer

Ursula A. Matulonis, MD

Ursula A. Matulonis, MD is Chief of the Division of Gynecologic Oncology at the Dana-Farber Cancer Institute and Professor of Medicine at Harvard Medical School. She is the first recipient of the Brock-Wilson Family Chair at the Dana-Farber Cancer Institute. She co-leads the Gynecologic Cancer Program within the Dana-Farber/Harvard Cancer Center and the Ovarian Cancer Specialized Program in Research Excellence (SPORE) grant from the National Cancer Institute. Her research focuses on developing new targeted therapies for gynecologic malignancies, with a specific interest in ovarian cancer and endometrial cancer.

Dr. Matulonis has led several PARP inhibitor, anti-angiogenic agent, immunotherapy, and combination trials for ovarian cancer in the United States and internationally. Dr. Matulonis serves on the Massachusetts Ovarian Cancer Task Force, chairs the Gyn subcommittee of the Alliance cooperative group, and the Scientific Advisory Board for the Ovarian Cancer Research Alliance, the Rivkin Foundation, the Clearity Foundation, and Overcome. She has received the Dana-Farber Dennis Thompson Compassionate Care Scholar award, the Lee M. Nadler "Extra Mile" Award, the Clearity Foundation award, the Zakim Award at Dana-Farber for patient advocacy, and recently in 2020, the Albany Medical College Alumni Association Distinguished Alumna Award. She has been named one of Boston's Best Physicians in Medical Oncology by Boston Magazine numerous times. Dr. Matulonis is also a recipient of grant funding from the Breast Cancer Research Foundation examining differences between ovarian cancer, endometrial cancer and breast cancer.

After receiving her MD from Albany Medical College, she completed an internship and residency at the University of Pittsburgh, followed by a medical oncology fellowship at Dana-Farber Cancer Institute in Boston, MA.