Hair Relaxer / Chemical Straightener Litigation

In October 2022, a landmark study by the National Institutes of Health — part of the Sister Study, a prospective cohort of nearly 34,000 women — found that women who used chemical hair straightening products more than four times per year had approximately 2.55 times the risk of developing uterine cancer compared to non-users (HR 2.55, 95% CI 1.46–4.45).

The findings ignited a wave of litigation because the products at issue — chemical relaxers, straighteners, and keratin treatments — have been disproportionately marketed to and used by Black women in the United States. An estimated 90% of chemical relaxer users are Black women, many of whom begin using the products in childhood. The litigation carries significant environmental justice and racial equity dimensions that have drawn attention from civil rights organizations and public health advocates.

Chemical analysis of hair straightening products has identified numerous endocrine-disrupting chemicals (EDCs) including formaldehyde and formaldehyde-releasing agents, phthalates (plasticizers linked to hormonal disruption), parabens (preservatives with estrogenic activity), cyclosiloxanes, and bisphenol-A. These substances can be absorbed through the scalp — which may be further damaged by chemical burns from the products themselves, increasing absorption rates.

Plaintiffs allege that manufacturers knew or should have known about the presence of EDCs and their health risks but continued to market the products without warnings, particularly targeting Black women and girls through culturally specific advertising campaigns and marketing strategies that promoted European beauty standards.

The 2022 NIH Sister Study is the primary epidemiological evidence. The study found that frequent use of hair straightening products (more than 4 times per year) was associated with a 2.55-fold increase in uterine cancer risk (HR 2.55, 95% CI 1.46-4.45). The association was consistent across racial groups but disproportionately impacts Black women due to dramatically higher usage rates — an estimated 90% of chemical relaxer users in the United States are Black women.

Additional research published in the Journal of the National Cancer Institute and Environmental Research has documented elevated levels of phthalates and other EDCs in the blood and urine of women who use chemical hair products. EDCs can mimic estrogen, interfere with hormone signaling, and promote the growth of hormone-sensitive cancers. The uterus is a particularly estrogen-responsive organ, which may explain the strong association with uterine cancer specifically.

A 2023 study in the journal Environmental Health Perspectives found that hair product use was associated with elevated urinary levels of multiple EDCs, with particularly high levels in Black women. Researchers noted that the scalp — especially when chemically irritated by relaxer products — may serve as a particularly efficient absorption route for these chemicals.

The FDA proposed banning formaldehyde-based hair straightening products in 2024, citing cancer risks to both consumers and salon workers who face occupational exposure. This regulatory action adds additional weight to plaintiffs' causation arguments.

Areas of scientific development include research into specific dose-response relationships, the contribution of individual chemicals versus chemical mixtures, and the long-term effects of childhood exposure.

Eligible individuals may include women who regularly used chemical hair straightening or relaxer products for extended periods — particularly products containing formaldehyde, phthalates, parabens, or other endocrine-disrupting chemicals — and were subsequently diagnosed with uterine cancer, endometrial cancer, ovarian cancer, uterine fibroids, or endometriosis.

The affected population is disproportionately Black women, who comprise the overwhelming majority of chemical relaxer users in the United States. Many women began using these products in childhood or adolescence, resulting in decades of cumulative exposure.

This eligibility information is general and informational only. Whether you have a viable legal claim depends on the specific facts of your situation and the laws of your jurisdiction. Consult a licensed attorney.

MDL No. 3060 continues to grow rapidly in the Northern District of Illinois before Judge Mary M. Rowland. As of March 2026, the MDL has surpassed 11,000 cases and continues to grow at approximately 247 new filings per month.

Daubert motions challenging the admissibility of plaintiffs' expert scientific testimony are due April 1, 2026 — a critical milestone that will determine whether the scientific evidence is sufficient to proceed to trial. The outcome of these Daubert challenges will significantly shape the litigation's trajectory.

Bellwether trial preparation is targeting 2027. Discovery has produced internal manufacturer documents that plaintiffs allege show awareness of endocrine-disrupting chemicals in products marketed primarily to Black women.

State court cases are also proceeding in several jurisdictions.

L'Oréal USA, the largest defendant, has argued that its hair care products meet all regulatory requirements and that the scientific evidence linking hair relaxers to cancer is insufficient to establish causation. The company points to the limitations of the NIH Sister Study — including its reliance on self-reported product use and the relatively small number of uterine cancer cases — as grounds for challenging causation.

Defendants collectively argue that the presence of certain chemicals in their products does not establish that those chemicals caused cancer in any individual plaintiff, and that the epidemiological evidence, while suggestive, does not prove causation. They are expected to challenge plaintiffs' expert testimony through Daubert motions due April 1, 2026.

Some defendants have argued that they relied on FDA regulatory standards for cosmetic products and that their products were safe when used as directed.

No settlements have been reached. The litigation is in its discovery and Daubert motion phase, with bellwether trials targeted for 2027. Settlement negotiations typically do not begin in earnest in a mass tort until after Daubert rulings and initial trial outcomes.

Past settlement amounts in other mass tort litigations are not a guarantee of results in this case.