Are chemical hair relaxers messing with your period and cycle?
Yes. Frequent relaxer use is linked to longer, heavier, and more painful periods.
What's actually in it
Chemical hair straighteners and relaxers usually contain parabens, phthalates, and lye-based agents that break the bonds in your hair. Many also release formaldehyde when heated. The mix soaks into the scalp, which is one of the most absorbent areas of skin.
The scalp drains into a network of blood vessels that feed the rest of the body, including the uterus and ovaries.
What the research says
A 2026 study in J Womens Health followed thousands of women and matched relaxer use with their menstrual records. Women who relaxed often reported longer periods, heavier bleeding, and worse cramps. The link got stronger the longer the women had been using the products.
A separate 2026 study in J Natl Cancer Inst also tied relaxer use to higher rates of non-reproductive cancers, suggesting the body-wide effect is real.
If you want to relax less often, switch to heat-based styling with low-tox products and stretch out time between treatments. Look for relaxers labeled formaldehyde-free and paraben-free, and ask the salon to ventilate well.
The research at a glance
| Study | Journal | Year |
|---|---|---|
| Use of Chemical Hair Straighteners and Menstrual Disturbances. | J Womens Health | 2026 |
| Use of hair straighteners and chemical relaxers and incidence of non-reproductive cancers. | J Natl Cancer Inst | 2026 |
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