Hair dye products aren’t linked to cancer — with a few key exceptions

BOSTON, Mass. — If you’ve ever been to a beauty salon, you may have noticed some of the strict health and safety rules workers must follow. Some of this has to do with groups like the Centers for Disease Control and Prevention labeling exposure to hair dyes as a possible cause of cancer. So what does this mean for people who color their own hair at home? A four-decade-long study has come to the conclusion that these products don’t come with the same risks.

Researchers say there’s little evidence getting rid of your grays at home will lead to most cancers. They add there are some important exceptions.

The study published by The BMJ followed more than 117,000 women from the Nurses’ Health Study for 36 years starting back in 1976. The report, based at Brigham and Women’s Hospital, looks at hair dye exposure and each participant’s risk for chronic disease.

Researchers say between 50 and 80 percent of women and 10 percent of men over 40 years-old use hair dyes in the United States and Europe. Permanent dyes are considered to be a more aggressive form of chemical compounds than natural hair coloring. About four in five people use permanent hair dyes in the U.S. and Europe. Study authors say this number is even higher in Asia.

The results reveal women who use permanent hair dyes face no increased risk of developing most forms of cancer. This includes cancer of the bladder, brain, colon, kidney, lung, blood, and the immune system. Most varieties of skin cancer (cutaneous squamous cell carcinoma and melanoma) and breast cancer (estrogen receptor positive, progesterone receptor positive or hormone receptor positive) are also unaffected by using hair dye.

Good news for hair dye users, but there are exceptions

While the overall picture is positive, permanent dyes slightly increased the risk for basal cell carcinoma of the skin. This link was found to be higher in women with naturally light hair.

There is also a slightly higher chance for three forms of breast cancer (estrogen receptor negative, progesterone receptor negative, and hormone receptor negative) and ovarian cancer in women using permanent dyes. The chances of developing cancers also appear to go up according to the cumulative amount of dye being used.

For women with darker hair, the study notes a slight increase in the chances to develop Hodgkin’s lymphoma. Study authors caution that all these increases appear in patients using permanent dyes only. Natural hair coloring did not impact the chances of developing any forms of the disease.

“Possible explanations could be that shades of permanent hair dyes are associated with the concentration of ingredients, with darker colors having higher concentrations,” the authors say in media release.

Adding diversity to the study

Researchers caution that this decades-long report only explores the link between hair dye and cancer, but not the cause. They add that further investigations will need to include a wider range of participants. The original report includes mainly white women of European ancestry.

Regardless of the drawbacks, study authors say the findings “offer some reassurance against concerns that personal use of permanent hair dyes might be associated with increased cancer risk or mortality.”

Both the World Health Organization and the CDC list occupational exposure to these dyes as a probable carcinogen. To date, neither group has ever made the same claim about personal hair care products due to lack of evidence.

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