Research late last year found hair dye and straighteners may have a disruptive effect on women’s hormones, Insider previously reported.
Specifically, those products were associated with small increases in breast cancer risk. Most at risk, according to the study, were Black women, who are much more likely than white women to alter their hair with chemical-laden formulas, sometimes including known carcinogens like formaldehyde and coal tar.
A 2020 study published in The BMJ found permanent hair dyes were linked to breast cancer, ovarian cancer, and basal carcinoma.
Temporary hair dyes were not associated with cancer risk, however, and permanent dyes didn’t appear to increase the risk of other types of cancer.
A limitation to this study it that it mainly included white women, all of whom were healthcare professionals, so it’s not clear if the results apply to other demographics.
There’s also a lot we still don’t know about how the amount or frequency of exposure makes a difference for the health risks of hair dyes, or even what types might be to blame.
The researchers concluded that more research is needed to understand who might be at risk, and how concerned we should be.