Hair Relaxers and Cancer: What the Research Shows and Where the Lawsuits Stand (2026)

Key takeaways (as of September 17, 2026)

  • Large studies have found associations, not proof of cause. In the NIH Sister Study, women who used chemical straighteners more than four times a year had an estimated 4.05% risk of uterine cancer by age 70, versus 1.64% for never-users.
  • The pattern has repeated in other groups. The Black Women's Health Study linked long-term relaxer use to higher uterine cancer risk in postmenopausal women. Other Sister Study analyses reported links with ovarian cancer and, in 2025, some non-reproductive cancers.
  • No study has pinned down a specific ingredient. Researchers did not have brand or formula data.
  • Litigation is large and unresolved. Federal MDL 3060 in Chicago had 12,129 pending cases on September 1, 2026. No bellwether trial has occurred and no global settlement has been announced.
  • Arizona sued L'Oréal on September 9, 2026, alleging consumer fraud; L'Oréal says the claims lack legal or scientific merit.

This article summarizes research and legal developments. It is not medical or legal advice. Talk to a doctor about your personal health risks and a licensed attorney about legal questions.

Why this question matters

Chemical relaxers and straighteners permanently change the structure of textured hair, and they have been used for generations, especially by Black women, often starting in childhood. When NIH researchers reported a link with uterine cancer in 2022, it prompted thousands of lawsuits, calls for an FDA formaldehyde ban, and hard questions for stylists who specialize in relaxer services.

Understanding the evidence carefully matters for everyone: clients deciding about their next retouch, stylists advising them, and anyone reading headlines about lawsuits.

What the research shows

The 2022 NIH Sister Study (uterine cancer)

The study that started the current wave followed 33,497 U.S. women ages 35–74 for about 11 years; 378 developed uterine cancer (NIH news release, Oct. 17, 2022; published in the Journal of the National Cancer Institute).

  • Women who reported using straightening products more than four times in the previous year were more than twice as likely to develop uterine cancer as non-users.
  • Estimated risk by age 70: 1.64% for never-users vs. 4.05% for frequent users.
  • About 60% of participants who reported straightener use identified as Black. The researchers did not find the association itself differed by race, but Black women's higher use means a greater potential impact.
  • Limitation the authors named: they "did not collect information on brands or ingredients."

Put plainly: uterine cancer is still uncommon, and a higher relative risk translates to a few extra cases per hundred frequent users over decades, based on these estimates.

Black Women's Health Study (2023)

Boston University researchers followed 44,798 Black women with an intact uterus from 1997 to 2019; 347 developed uterine cancer (Environmental Research abstract; BU news release, Oct. 11, 2023).

  • Across all women, heavy use (15+ years, 5+ times a year) was not statistically significantly linked to uterine cancer (hazard ratio 1.18; 95% CI 0.81–1.71).
  • Among postmenopausal women, heavy use was linked to about 64% higher risk (HR 1.64; 95% CI 1.01–2.64), and 20+ years of use to about 71% higher risk (HR 1.71; 95% CI 1.08–2.72).
  • No association was seen in premenopausal women.

This mixed result is important: it supports a possible link in one group while showing the overall picture is not simple.

Ovarian cancer (Sister Study, 2021)

Among 40,559 women with a mean 10-year follow-up and 241 ovarian cancer cases, frequent use of straighteners/relaxers or pressing products (more than four times a year) was associated with higher ovarian cancer risk (HR 2.19; 95% CI 1.12–4.27) (Carcinogenesis, 2021). The confidence interval is wide, reflecting relatively few cases.

Other cancers (Sister Study, 2025)

A 2025 JNCI analysis of 46,287 women followed for an average of 13.1 years looked beyond reproductive cancers. Compared with non-users, straightener use was associated with higher risk of pancreatic cancer (HR 2.66; 95% CI 1.25–5.66) and thyroid cancer (HR 1.71; 95% CI 1.01–2.89); estimates for non-Hodgkin lymphoma and kidney cancer were elevated but not statistically significant (Dermatology Times summary of Bailey et al.). The authors noted exposure was measured only at baseline, product formulas were unavailable, pressing devices may have been misclassified as chemical products, and there were few cases among Black women.

Reviews of the evidence

An October 2024 evidence scan from Kaiser Permanente Washington's ACT Center concluded that "good quality research has demonstrated an association between hair relaxer use and ovarian and uterine cancers," while flagging small samples, inconsistent exposure measures, changing formulas and proprietary ingredient data as limits (ACT Center). Breast cancer findings across studies were described as mixed.

What could explain a link?

Researchers have pointed to possible endocrine-disrupting chemicals (such as some phthalates and parabens), formaldehyde-releasing ingredients, and scalp burns or lesions that may increase absorption. These are hypotheses. No study to date has tested specific relaxer formulas against cancer outcomes in people.

Confidence summary: An association between frequent, long-term relaxer/straightener use and uterine cancer is supported by two large U.S. cohorts (medium-high confidence in the association). Whether relaxers cause these cancers, and which ingredients might be responsible, is not established (low confidence).

Where the lawsuits stand

Federal MDL 3060 (Northern District of Illinois)

Since early 2023, federal cases alleging that relaxers caused uterine, ovarian or other cancers have been consolidated before U.S. District Judge Mary M. Rowland in Chicago as In re Hair Relaxer Marketing, Sales Practices, and Products Liability Litigation, MDL No. 3060.

  • Case count: 12,129 actions pending, 16,561 total filed over the life of the MDL, per the Judicial Panel on Multidistrict Litigation's September 1, 2026 report.
  • Defendants named in court filings include L'Oréal USA, Revlon, Strength of Nature, Namaste, House of Cheatham, Luster Products, Sally Beauty, Avlon, Dudley Beauty and others (Joint Status Report, May 14, 2026).
  • Bellwethers: On April 2, 2026, the judge selected 10 cases for the bellwether trial pool (King Law case tracker). Bellwether trials test how juries respond; they are not class actions.
  • Expert challenges: Defendants filed motions on May 5, 2026, to exclude plaintiffs' general-causation experts under Rule 702 (Joint Status Report). A ruling had not been reported as of our research date. This decision is pivotal: if the science experts are excluded, many claims could fail.
  • Schedule: Law-firm trackers report expert discovery closing November 16, 2026, with summary judgment and expert motions due in December 2026, and first federal trials expected no earlier than 2027 (Marin Murphy Law, Aug. 2026). We could not verify these dates on the court docket directly.
  • Settlement: No global settlement has been announced. A mediator was appointed in 2025.

State courts

Cases are also moving in state courts. The May 2026 joint status report listed trial settings in St. Clair County, Illinois (September 28, 2026) and Cook County, Illinois (November 2, 2026), with later Cook County cohorts in 2027 (Joint Status Report). Trial dates frequently move; we could not confirm whether these remain on calendar.

Arizona's consumer fraud lawsuit against L'Oréal (September 2026)

On September 11, 2026, Arizona Attorney General Kris Mayes announced a consumer fraud lawsuit against L'Oréal USA and its SoftSheen-Carson business, alleging the company failed to disclose cancer risks linked to relaxers marketed largely to Black women and, in some cases, children (Arizona AG press release). According to Consumer Reports, the complaint names Dark & Lovely, Optimum and Mizani products and seeks warnings and monetary relief. L'Oréal USA told Consumer Reports the allegations "have neither legal nor scientific merit." These are allegations, not findings.

What a lawsuit does and doesn't prove

Filing counts show how many people have sued, not what caused anyone's illness. Courts decide causation case by case, and judges screen scientific testimony before juries hear it. No court has yet found that relaxers cause cancer.

Practical guidance for clients

  • Talk to your doctor if you are worried, especially about symptoms like abnormal or postmenopausal bleeding, which should always be checked regardless of hair history.
  • Consider frequency. The strongest associations involve frequent, long-term use.
  • Protect your scalp. Don't relax a scratched, irritated or freshly braided scalp; burns may increase absorption.
  • Explore alternatives if you want less chemical exposure: wearing natural textures, silk presses with heat protection, or stretching time between retouches. Each has trade-offs, including heat damage.
  • Think carefully about children. Arizona's lawsuit alleges some relaxers were marketed to children; talk with a pediatrician and a licensed stylist before any chemical service on a child.

Practical guidance for stylists

  • Keep client records of product, frequency and scalp condition.
  • Base the scalp, avoid overlapping onto previously relaxed hair, and stop at any burning.
  • Wear gloves and ventilate; you have more cumulative exposure than any single client.
  • Answer questions honestly: "Studies have found associations, especially with frequent use, but a cause hasn't been proven and research continues."
  • Report serious reactions to the manufacturer and FDA.

What we don't know yet

  • Which ingredients, if any, are responsible.
  • Whether today's formulas carry the same risk as those used by study participants decades ago.
  • How the MDL judge will rule on expert testimony, and when or whether a first trial will happen.
  • Whether the FDA's long-delayed formaldehyde rule will be proposed (its target has slipped repeatedly).

FAQ

Do hair relaxers cause cancer? Studies show associations between frequent, long-term use and uterine and ovarian cancer, but they have not proven causation or identified a specific ingredient.

Is "no-lye" relaxer safer? The major studies did not distinguish lye from no-lye formulas, so there is no evidence either way on cancer risk.

How many hair relaxer lawsuits are there? 12,129 cases were pending in federal MDL 3060 as of September 1, 2026, plus cases in state courts.

Has anyone won a hair relaxer lawsuit? As of September 17, 2026, we found no reported verdict in the federal MDL and no announced global settlement.

Should I stop relaxing my hair? That is a personal choice. Discuss your risk factors with a doctor and weigh frequency, scalp health and alternatives with your stylist.

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