Arizona has become the first US state to bring a consumer fraud lawsuit against L'Oréal over its chemical hair relaxers. On September 10, Arizona Attorney General Kris Mayes sued L'Oréal SA and its US subsidiary, alleging the cosmetics giant knew, or “should have known,” about potential cancer risks associated with its hair-straightening products but failed to warn consumers. L’Oréal disputes the allegations and says the underlying research did not establish causation.
This is not L’Oréal’s first legal fight over hair relaxers. L'Oréal is among the defendants facing more than 12,000 pending lawsuits consolidated in federal multidistrict litigation (MDL) over alleged cancer risks associated with chemical hair relaxers.
But this case isn’t the same. The plaintiffs in the federal MDL allege personal injury and are looking to establish that hair relaxers caused uterine and ovarian cancers. Arizona’s case, by contrast, centers on whether L’Oréal knew about potential cancer risks associated with its hair relaxers and concealed them from consumers.
The complaint accuses L’Oréal of advertising and selling its chemical hair relaxers (Dark and Lovely, Optimum, and Mizani) to Black and Brown women and hair salons in Arizona, while “concealing the devastating carcinogenic risks associated with those products.”
“L'Oréal knew or should have known about the dangers associated with these toxic hair- straightening products,” Attorney General Kris Mayes said in a press release. “Yet, instead of warning their consumers, they put profits over the safety of women and children.”
The lawsuit also contends that since the 1970s, L’Oréal has perpetuated Eurocentric beauty standards through the marketing of its hair-straightening products to both women and girls. “Defendants engaged in a marketing scheme premised heavily upon branding and slogans reinforcing straight hair as the quintessential standard of beauty and professionalism.”
Arizona will build its case around decades of scientific studies, arguing that L’Oréal, as a global cosmetics giant with extensive scientific resources, should have known about the potential risks of its hair-straightening products and disclosed them to consumers.
While several studies have found an association, researchers have not established a causal link between ingredients in hair relaxers and cancer. Arizona’s complaint leans heavily on a 2022 NIH-funded observational study, part of the long-running Sister Study cohort, which tracked hair-product use and uterine cancer diagnoses among 33,497 US women. It found that women who used chemical hair straighteners or relaxers more than four times per year were more than twice as likely to develop uterine cancer as non-users. The findings show an association, not causation.
But researchers have identified limitations in the study: The 33,497 number made headlines, but the findings were based on just 14 cases among frequent users of hair-straightening products. Critics also argued that uterine cancer can take years to develop, so the analysis should have excluded cancers diagnosed shortly after the study began. Other factors may have also influenced the results, including oral contraceptive use, which independently affects uterine cancer risk.
“These limitations need to be considered when examining the results of this study,” said epidemiologist Mahyar Etminan, an associate professor at the University of British Columbia, in a 2022 follow-up critique in the Journal of the National Cancer Institute. “Future studies that can better control for biases including confounding and disease latency bias are needed to confirm these results.”
This study is a key piece of evidence in the 12,000 pending federal cases. The plaintiffs’ bar has been in purgatory for months, knowing that if the judge grants L’Oréal’s and the other defendants’ Daubert challenges, their cases could be dead in the water. Under the Daubert standard, federal judges determine whether expert testimony is sufficiently reliable and relevant to reach a jury.
While the Daubert challenge may pertain to multidistrict litigation and Arizona v. L’Oréal is a consumer fraud case, the outcome of that Daubert ruling could still strengthen or weaken the scientific foundation on which Arizona is relying. If the judge allows the study’s authors to testify, it bolsters Arizona’s position, while exclusion of the experts would give L’Oréal ammunition to attack the scientific foundation Arizona relies on.
L’Oréal’s defense will likely focus on severing any link between its products and cancer by challenging the scientific studies cited in the complaint. A L’Oréal spokesperson told Courthouse News that the cited studies concluded that more research was needed and that no causal connection had been made. “L’Oréal’s highest priority is the health and wellbeing of all our consumers,” the spokesperson added. “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.”
Arizona is betting there is a meaningful gap between “the science didn’t prove it” and “we didn’t know enough to warn consumers.” L’Oréal is betting there isn’t. If Arizona wins, it could provide other states with a roadmap for pursuing similar consumer fraud cases, potentially turning a single state lawsuit into a much larger legal problem for L’Oréal and other cosmetic manufacturers. But the implications stretch beyond hair relaxers. The case ultimately tests how much a beauty company needs to know about a potential risk before it needs to tell consumers.
