The hair-relaxer cases turn an epidemiological association into a contested legal question

What plaintiffs allege

The federal lawsuits allege that chemical hair-straightening or relaxer products increased risks of uterine, ovarian or breast cancer and that manufacturers failed to warn. The JPML treated those as shared allegations when it created MDL 3060; it did not decide their truth.

The cases are pending in the Northern District of Illinois before Judge Mary Rowland. JPML listed 11,779 actions pending on August 3, 2026.

What the original study found

A prospective analysis of 33,947 Sister Study participants reported an association between frequent straightener use and incident uterine cancer. Participants reported product use themselves, and the observational design cannot by itself establish that a particular product caused a particular cancer.

The study deserves careful attention, including because these products have been marketed and used disproportionately by Black women. That context does not erase the study's limits or turn a population association into an individual conclusion.

What the available record does not resolve

Responding defendants opposed centralization, but that was a procedural position rather than one merits defense. The official records reviewed here do not supply a single current causation position fairly attributable to every defendant or a final outcome resolving general causation.