Unclear
Permanent hair dye and straighteners
chemical hair products. Personal care.
- Verdict
- UnclearThere isn't enough human evidence to say either way.
- How sure
- Rung 2 · LimitedFew, small or conflicting human studies, or only indirect measures such as blood markers.
- How big
- 9% higher breast cancer risk with regular use in one large study, and 45% higher among Black women.
The rung shows how sure the science is, not how big the effect is. How to read these ratings
Cancers affected
Breast
What the evidence shows
In 46,709 women, regular permanent dye use was linked to 9% higher breast cancer risk, and 45% higher among Black women; straighteners were also linked. Earlier studies were mixed and this was observational.
What to do
No firm recommendation yet. Using these products less often is a reasonable precaution.
Sources
To take it to your doctor, print this page.
Step by step
For the whole picture, from prevention and screening to treatment and life after, see the breast cancer page.