Hair Relaxers and Uterine Cancer

Research has linked uterine cancer to the frequent use of hair relaxers, which are chemical hair straighteners. The Sister Study discussed in detail below found that women using chemical hair straighteners have a higher risk of uterine cancer than women not using these products. The researchers uncovered no similar connection with other hair products, like dye, bleach and highlights.

Read more about studies linking hair relaxers to uterine cancer below.

The Sister Study

The Sister Study was a comprehensive study conducted by the National Institute of Environmental Health Sciences (NIEHS). The study began in 2003 and followed nearly 34,000 U.S. women ages 35 to 74 for more than a decade. The researchers examined risk factors for various female cancers. Among those who participated, 378 developed uterine cancer.

Here are a few key takeaways:

• Women who used hair relaxers more than four times during the previous year were more than twice as likely to develop uterine cancer than women who didn’t use chemical hair straighteners.
• The study concluded that approximately 1.64% of those who hadn’t used hair relaxers would develop uterine cancer by age 70. However, the uterine cancer risk for those who frequently used the products was estimated at 4.05%.
• Black women made up approximately 60% of the participants. The researchers found that Black women might deal with more adverse health effects due to their common use of hair relaxers, the presence of toxic chemicals in chemical straighteners and the relatively young ages at which they might begin using the products.

Black Women’s Health Study

In 2023, Boston University published a Black Women’s Health Study. It found a relationship between extended use of chemical hair straighteners and uterine cancer in women who’ve gone through menopause.

The study of nearly 45,000 women followed those with no history of cancer for as long as 22 years, comparing rates of uterine cancer among those who used hair relaxers to those who didn’t.

The researchers concluded:

• Women who used hair straighteners more than twice a year or for more than five years had a 50% or higher risk of uterine cancer than women who never or rarely used chemical hair relaxers.
• Black women experience aggressive forms of uterine cancer at higher rates than non-Hispanic white women. They are almost twice as likely to die from the disease.

Research has found a link between dangerous health conditions and harmful chemicals contained in chemical hair relaxers and straighteners. Associated health conditions include uterine cancer in women who use these products.

Harmful chemicals that hair relaxers and straighteners may contain include:

• Cyclosiloxanes: Research has connected cyclosiloxanes with neoplastic responses (the uncontrolled and excessive growth of cells), leading to uterine tumors in rats.
• Di (2-ethylhexyl) phthalate (DEHP): A toxic man-made chemical, DEHP has been classified by the International Agency for Research on Cancer (IARC) as potentially carcinogenic to humans.
• Endocrine-disrupting chemicals (EDCs): These chemicals, or combinations of chemicals, disrupt the human endocrine system.
• Formaldehyde: A common ingredient in chemical hair straighteners, even in products labeled as formaldehyde-free, formaldehyde enters the air when the relaxer is heated during use. The U.S. Department of Health and Human Services’ National Toxicology Program (NTP) and the World Health Organization’s International Agency for Research on Cancer (IARC) have both classified formaldehyde as a known human carcinogen.
• Parabens: EDCs used in chemical straighteners. Parabens may affect estrogen levels. Research has linked parabens to uterine fibroid tumors, premature puberty and endocrine disruption.
• Phthalates: These are chemicals used to make fragrances in cosmetics more stable and help topical products adhere to and pass through skin and hair. Phthalates are known EDCs that pose a risk to human health.

What hair relaxer brands cause uterine cancer?

Certain hair relaxers may cause uterine cancer. These hair relaxers include products made by Godrej Consumer Products Ltd, L’ORÉAL USA, Namaste Laboratories, LLC, Revlon and others. Because these companies didn’t warn consumers about the potential harm in their products, many lawsuits allege users experienced dangerous side effects — including cancer. Thousands of toxic exposure lawsuits have been filed by individuals diagnosed with cancer.

Yes, people began to file hair relaxer lawsuits after a 2022 study connected chemical hair relaxers to an increased risk of uterine cancer. As of March 2026, more than 11,000 such claims are consolidated into multidistrict litigation in MDL 3060. These lawsuits assert that the chemicals contained in hair relaxer products cause serious health conditions, including cancer and other medical issues.

Hair relaxer cases allege that the defendants:

• Knew or should have known of the risks associated with hair-relaxing chemicals
• Marketed dangerous chemical straighteners without warning consumers
• Misrepresented hair relaxer products as “safe” and “natural”
• Reinforced traditional standards of beauty and negative stereotypes about textured hair

Hair relaxers and cancer lawsuit eligibility

In order to be considered eligible for a hair relaxer lawsuit, individuals must meet the following criteria:

• They regularly used chemical hair relaxer products for several years
• They received a diagnosis of uterine, ovarian or endometrial cancer
• They have medical documentation linking hair relaxer chemical exposure to the medical condition

A hair relaxer cancer lawyer at Motley Rice can review your specific claim and help determine your eligibility based on the unique facts of your case.

Is there an FDA ban on hair-relaxing products?

No, the FDA has not banned hair-relaxing products. In 2023, the U.S. Food and Drug Administration (FDA) proposed a ban on formaldehyde and formaldehyde-releasing chemicals in hair relaxers due to its connection to cancer and other serious, long-term health effects. However, to date, the FDA has not yet implemented the proposed rule.

What other types of cancer are linked to hair relaxers?

Apart from uterine cancer, hair relaxers have allegedly been linked to ovarian cancer and endometrial cancer. The Sister Study researchers found that ovarian cancer risk doubled in women who used hair relaxers more than four times in the previous year, compared to those who didn’t.

Which hair relaxers cause cancer?

Hair relaxer products that may lead to toxic chemical exposure and cancer are made by brands like Godrej Consumer Products Ltd, L’ORÉAL USA, Namaste Laboratories, LLC, Revlon and others. Product names include Dark & Lovely, Just For Me and ORS Olive Oil.

What is the most common symptom of uterine cancer?

Uterine cancer has many common symptoms, including:

• Pain in the lower abdomen
• Pelvic cramping directly below the stomach
• Prolonged, heavy or frequent vaginal bleeding in women over 40
• Slight or moderate vaginal bleeding or spotting after menopause
• Thin, clear or white vaginal discharge in postmenopausal women
• Vaginal bleeding between periods in premenopausal women

Many people have been impacted by ovarian, uterine or endometrial cancers allegedly caused by using chemical hair relaxers. If you believe you’ve been similarly impacted by toxic exposure to hair-relaxer chemicals, consider discussing your options with an attorney who has experience in multidistrict litigation.

Motley Rice leads litigation brought by thousands of women harmed by defective products. Our law firm has extensive experience litigating product liability lawsuits for women who:

• Developed ovarian cancer after using talc-based baby powder for feminine hygiene
• Suffered breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) allegedly caused by Allergan breast implants
• Endured severe complications allegedly caused by birth control devices such as Essure® and Paragard® and complications arising from the use of transvaginal mesh

Read more on our toxic exposure litigation experience.