Uterine Cancer and Chemical Hair Relaxers

Last updated: March 2026

What Is Uterine Cancer?

Uterine cancer (also called endometrial cancer or cancer of the uterus) is cancer that begins in the cells lining the uterus — the endometrium. It is the most commonly diagnosed gynecologic cancer in the United States, with approximately 67,000 new cases diagnosed each year.

Uterine cancer rates in the United States have been rising for decades, and they have risen disproportionately among Black women. Black women are diagnosed with uterine cancer at higher rates than white women and die from it at more than twice the rate. A growing body of research links this disparity, at least in part, to the disproportionate use of chemical hair relaxers by Black women.

Symptoms of Uterine Cancer

The most common symptom of uterine cancer is abnormal vaginal bleeding — including bleeding after menopause, unusually heavy periods, or bleeding between periods. Other symptoms may include:

• Abnormal vaginal discharge (watery, bloody, or foul-smelling)
• Pelvic pain or pressure
• Pain during intercourse
• Difficulty urinating
• Unintentional weight loss (in advanced disease)

Important: If you are experiencing any of these symptoms, seek medical attention promptly. Early detection significantly improves treatment outcomes. This page is not a substitute for medical advice.

How Hair Relaxers Increase Uterine Cancer Risk

Uterine cancer is predominantly a hormone-driven cancer. The uterine lining (endometrium) is highly sensitive to estrogen. When cells in the endometrium are exposed to excessive or inappropriate estrogenic stimulation, they can grow abnormally and become cancerous.

Chemical hair relaxers contain multiple chemicals that mimic or increase estrogen activity in the body:

• Parabens — bind to estrogen receptors and trigger estrogenic responses
• Phthalates — disrupt hormone metabolism, including estrogen processing
• BPA (Bisphenol A) — a strong xenoestrogen that activates estrogen receptors
• Formaldehyde-releasing agents — classified carcinogens that cause direct DNA damage

When applied to the highly permeable scalp skin and absorbed into the bloodstream, these chemicals circulate throughout the body — including to the uterus and ovaries. Regular, long-term use (as recommended by these products) means repeated, chronic exposure to hormone-disrupting chemicals over years or decades.

The NIH Sister Study — 2.55× Higher Risk

The NIH Sister Study, published in October 2022, was a landmark 11-year study of 33,497 women. The findings on uterine cancer were striking:

• Women who used hair straightening products more than 4 times per year had 2.55× the risk of uterine cancer compared to non-users
• The association was strongest for frequent and long-term users
• The study found that approximately 60% of Black women reported using hair straightening products, compared to about 10% of non-Black women
• Researchers noted that "if our findings are confirmed, the straightener use could become an important modifiable risk factor for uterine cancer"

Who Is Most Affected?

Black women bear a disproportionate share of the harm from hair relaxer-associated uterine cancer for interconnected reasons:

• Higher use rates: Chemical hair relaxers have been marketed primarily to Black women and girls for generations
• Earlier start age: Many Black women began using relaxers as children — some as young as 5 years old
• Longer use duration: Many women used these products for 20, 30, or 40+ years
• Higher baseline cancer rates: Black women already have higher uterine cancer rates and significantly worse outcomes
• Cultural factors: Systemic pressure to conform to Eurocentric beauty standards drove continued use despite potential health concerns

Uterine Cancer in the Lawsuit — What Qualifies

Uterine cancer (endometrial cancer) is the primary qualifying diagnosis in the hair relaxer cancer litigation, with the strongest scientific evidence supporting the link. To qualify for a claim based on uterine cancer, you generally need:

• A formal diagnosis of uterine cancer (any stage)
• A history of chemical hair relaxer use, preferably regular or frequent use over a sustained period
• Use within your state's statute of limitations window (the discovery rule may extend your deadline)