Hair Dye Isn’t Giving Everyone Cancer

Why you probably don’t have to worry about dyeing your hair and breast cancer

Hair dye is in some ways the hero of modern cosmetics. Even a relatively short time ago, the main options were to go grey with age or look very odd, but now you can easily change your hair colour almost at whim*. It’s cheap, easy to do, and there’s some evidence that most women have tried it at least once in their lives.

And, according to the news, it’s also a terrifying chemical nightmare that’s giving you cancer.

Seriously, there have been a lot of scary headlines Source: Google

For anyone who’s ever dyed their hair — which includes somewhere between 50–75% of adult women — this must’ve been a scary week. But while the headlines and stories are frightening, in reality the science isn’t nearly as worrying as you might’ve heard.

Chances are you can keep dying your hair. It isn’t giving you cancer after all.

The Science

All of the media stories are reporting on the same study, that was recently published in the International Journal of Cancer, where scientists looked at the association between hair dyeing behaviour and future breast cancer risk. Basically, they asked a large group of women how often they dyed their hair, and followed up about 10 years later. Compared to the women who dyed their hair the least, women who dyed their hair a lot had an increased risk of breast cancer.

And from this, the headlines were born.

Pictured: Cancer, probably. Source: Unsplash

And on face value, the study sounds very robust. It was a large group of people — more than 50,000 women — and the follow-up was very good. The scientists even controlled for a range of factors that could influence both hair dyeing behaviour and breast cancer risk, in what’s known as controlling for confounders, which makes the results a bit less likely to be wrong.