What Is the Hair Relaxer Lawsuit About?

The claims are about cancer and reproductive harm. The Judicial Panel on Multidistrict Litigation says the cases share allegations that defendants' hair relaxer products contain phthalates or other endocrine-disrupting chemicals, and that using them caused or increased the risk of uterine, ovarian or breast cancer, endometriosis, uterine fibroids or other reproductive injuries. In February 2023 it centralized the federal cases as MDL No. 3060 in the Northern District of Illinois before Judge Mary M. Rowland. These are allegations.

A 2022 NIH study drew attention to the issue. The National Institute of Environmental Health Sciences reported that among 33,947 US women ages 35 to 74 in its Sister Study, followed for almost 11 years, those who reported frequent use of hair straightening products, more than four times in the previous year, were more than twice as likely to go on to develop uterine cancer as women who did not use them. The lead author estimated uterine cancer risk by age 70 at 1.64 percent for women who never used straighteners and 4.05 percent for frequent users. NIEHS says the researchers did not collect brand or ingredient information, but the paper notes that chemicals found in straighteners, such as parabens, bisphenol A, metals and formaldehyde, could be contributing.

Formaldehyde rules are still pending. The FDA says hair smoothing products often contain formaldehyde, also known as formalin and methylene glycol, which is released into the air as a gas when heated. An FDA entry in the federal Unified Agenda describes a rule that would prohibit formaldehyde and formaldehyde-releasing chemicals as ingredients in heated hair smoothing or straightening products, and lists the proposed rule stage for November 2026.