Thousands of women claim hair relaxers cause cancer, citing studies linking them to increased risks. Legal battles grow against major beauty brands.
DALLAS — Thousands of women across the country have sued major hair relaxer manufacturers and brand companies, claiming that chemical straightening products have led to uterine cancer and other health issues.
The lawsuits focus on findings from multiple scientific studies linking the long-term use of hair relaxers to potentially increased cancer risks.
Studies Raise Alarms Over Hair Relaxers
In October 2022, the National Institutes of Health (NIH) published the Sister Study, which tracked nearly 34,000 women of different races for almost 11 years. Researchers collected information for participants’ usage of a number of hair products like bleaches, hair dyes, perms and chemical straighteners.
While the data showed no significant links between most of the products and cancer, researchers reported that women who used chemical hair straighteners or relaxers more than four times a year were more than twice as likely to develop uterine cancer as those who never used the products.
Critics of the Sister Study argued that the researchers did not study the women for a long enough period and that they weren’t specific about the products in question -- lumping different types of products into one group.
But nearly a year later, another study came out with similar results.
“When we saw that they were seeing a positive association, we were very concerned that that’s just one study,” Dr. Kimberly Bertrand, an epidemiologist and assistant professor at the Boston University School of Medicine, said of the Sister Study. “Is that still true in another study? That’s what we call replications in this field. Seeing that paper and their results did really spark us to look at this more closely in our population.”
Dr. Bertrand is a co-researcher for the Black Women’s Health Study. The project, like the Sister Study, was searching for a connection between different exposures women face and adverse health outcomes. Bertrand’s study followed nearly 45,000 women -- who were all Black -- for more than 20 years.
“We wanted to understand whether women who had a history of using chemical hair relaxers had a higher risk of developing uterine cancer compared to women who didn’t or only occasionally used chemical hair relaxers,” Bertrand said. “Our results from the Black Women’s Health Study and the Sister Study were relatively consistent.”
The Black Women’s Health Study, published in October 2023, found post-menopausal women who used chemical hair relaxers for more than 15 years, or many times per year, had about a 60 percent increased risk of developing uterine cancer compared to women in the same age group who never used them or who only used them occasionally.
Targeted Marketing and Mystery Ingredients
One of the main takeaways from both studies is the specific impact on Black women whose natural curls, kinks and coils make them the target consumer for a product that functions as a straightening agent.
The National Institute of Health and the National Cancer Institute have published findings that indicate that Black women are also disproportionately impacted by uterine cancer and other adverse reproductive health conditions.
“Thinking about what are the unique experiences and exposures that Black women face in this country, one of the exposures potentially is chemical hair relaxers because these are products that are heavily marketed to Black women,” Bertrand said.
Critics also point out that the studies don’t specifically identify a certain brand, product or ingredient that could be harmful to women.
Bertrand, however, said there is a reason for that.
“Not only are these products heavily marketed to Black women, they also have proprietary formulations, and women don’t always know what’s in these products,” Bertrand said. “They’re minimally regulated by the FDA. One of the chemical classes we’re concerned about in these products is endocrine disruptors. These include parabens and phthalates, but you may not know that the product you’re using contains these chemicals because they’re not required to be listed on the label.”
While different relaxers have different ingredients, nearly all list “fragrance” or “parfum” as an ingredient. The FDA does not require manufacturers to delineate the specific chemicals in those ingredients. There have also been a number of studies that have already determined “fragrance” to be an endocrine disruptor -- meaning it can disrupt hormones and potentially cause health complications.
“I think women have a right to know what they’re exposed to and whether there’s potential toxicity to the chemicals they’re exposed to,” Bertrand said.
Growing Legal Battle
As awareness of these findings spread, lawsuits against hair relaxer companies began to mount. Attorney Brooke Cohen, a partner at the Cohen Hirsch law firm, represents about 100 women in cases against major beauty brands concerning this issue.
“Anytime there's a product that harms women, we think it’s important to get behind it because there has to be change,” Cohen said.
In February 2023, more than 50 lawsuits were gathered in a federal court in Chicago in what’s known as multi-district litigation, or MDL. Cohen said an MDL allows for plaintiffs and attorneys who sue the same defendants for the same issues to consolidate the work and cost, essentially making the process more balanced and efficient.
“If you have just one woman who got hurt who goes after them individually, it would be prohibitively expensive,” Cohen said. “They would not be able to be probably win. It would be a David and Goliath situation really, so in an MDL all the discovery, the fact finding and the evidence is shared across the plaintiffs, across the nation, and those costs are shared.”
As of February 2025, more than 9,800 cases have been filed in the MDL.
Defendants include multiple hair relaxer manufacturers, with L’Oréal as the largest named company. L’Oréal sells both at-home relaxers and professional-grade products under its SoftSheen-Carson brand.
L’Oréal and Industry Response
In a statement, L’Oréal defended its products, stating:
“Our highest priority is the health and wellbeing of all our consumers. Our products are subject to a rigorous scientific evaluation of their safety by experts who also ensure that we strictly follow all regulations in every market in which we operate.
L'Oréal does not add formaldehyde as an ingredient in any of its products in any market in the world. We welcome and support the U.S. Food and Drug Administration's (FDA) recent proposal across the entire beauty industry.
While we understand the desire of each plaintiff to find answers to and relief from their personal health concerns, we are confident in the safety of SoftSheen-Carson's products and believe the allegations made in these lawsuits have neither legal nor scientific merit.
The novel study upon which all these lawsuits is based recognized the need for further research and it made no finding of a causal connection between the use of those products and any conditions alleged by the plaintiffs. Tellingly, while the study clearly states that 'more research is warranted,' one of the lead researchers of the study has also acknowledged repeatedly that there could be other potential contributing factors to the health outcomes.”
Bertrand, while acknowledging the limitations of epidemiologic studies, emphasized that more than 20 years of research found an association between chemical hair relaxers and uterine cancer risk.
“No one can tell what caused any individual woman’s cancer. It’s like a multi-factorial disease ideology, so it’s a lot things factoring together. There’s no doctor or scientist on earth who could look at a tumor and say this was caused by x exposure…that’s just not a possibility,” Bertrand said. “That’s maybe what the manufacturers in these lawsuits are kind of hanging on, right, and it’s true. But when there are these associations, it makes you want to understand better.”
Bertrand also pointed out that previous studies have indicated that chemical hair relaxers have been linked to other health concerns.
“As early as 1997 is when we first started asking about women’s experience with using chemical hair relaxers,” Bertrand said. “…We published and found associations between use of chemical hair relaxers and uterine fibroids. We’ve seen modest associations for breast cancer, so these are reproductive outcomes we’ve been interested in for a long time.”
While she agreed with researchers who wrote in the Sister Study that more work would need to be done to determine a causal relationship, she said transparent ingredient labels would be an important, welcome first step.
“For example, manufacturers being required to actually list what the ingredients are, and then women will know what they’re being exposed to,” Bertrand said.
What's Next?
When it comes to the legal battle, written discovery in the MDL was due on February 28. Next, there will be what’s called a Bellwether Trial in which both the plaintiffs’ and defendants’ attorneys will be able to select some of the women whose cases are part of the suit to be tried first to get a gauge of what a formal trial would look like.
