Can hair dye use increase the risk of uterine fibroids?

What's actually in it

Hair dyes contain a cocktail of chemicals including aromatic amines, paraphenylenediamine (PPD), resorcinol, ammonia, and hydrogen peroxide. These chemicals absorb through the scalp during application. Darker dyes contain more aromatic amines, which are known endocrine disruptors. Many of these chemicals mimic or interfere with estrogen, which plays a key role in uterine health.

What the research says

A 2026 prospective study in Fertil Steril followed women over time to see whether hair dye use affected their risk of developing uterine leiomyomata (fibroids). The researchers tracked hair dye habits and new fibroid diagnoses.

Women who used hair dyes had a higher incidence of uterine fibroids compared to women who didn't use them. The association was strongest for women who used permanent dark dyes and those who dyed their hair more frequently.

Uterine fibroids are noncancerous growths that can cause heavy periods, pelvic pain, and fertility problems. They're driven by hormones, especially estrogen. The endocrine-disrupting chemicals in hair dye may feed fibroid growth by adding extra estrogen-like stimulation to uterine tissue.

Semi-permanent and temporary dyes contain fewer of the most concerning chemicals. Plant-based dyes like henna are an alternative, though they have a more limited color range. Spacing out dye sessions and choosing lighter colors can reduce exposure.