Researchers have been studying the possible link between hair dye and cancer for a long time, but results have been inconsistent. A recent study, published by the National Institutes of Health in 2019, suggests that breast cancer risk increased with more frequent use of these chemical hair products. This study found that women who use permanent hair dye and chemical hair straighteners have a higher risk of developing breast cancer than women who don’t use these products.
Particularly, this study found that women who used hair straighteners at least every five to eight weeks were about 30% more likely to develop breast cancer. While the association between straightener use and breast cancer was similar in African American and white women, straightener use was much more common among African American women.
It is important to note we are exposed to many things that could potentially contribute to breast cancer, and it is unlikely that any single factor explains a woman's risk. However, avoiding these chemicals might be one more thing women can do to reduce their risk of breast cancer.