Women who frequently dye their hair could have a higher risk of developing breast cancer, according to Professor Kefah Mokbel, a breast surgeon from Princess Grace Hospital in central London. After reviewing several studies, he found that women who color their hair are 14 percent more likely to be diagnosed with the disease than those who do not use any dyes, The Sunday Times of London reports.

'Although further work is required to confirm our results, our findings suggest that exposure to hair dyes may contribute to breast cancer risk,' Professor Mokbel wrote.

Typically, hair professionals advise women to touch up their hair color every four to six weeks. But Professor Mokbel recommends dying your hair no more than five or six times a year, as well as using products with natural ingredients like beetroot and henna.

The surgeon isn’t the first to find a connection between hair dye and breast cancer, however. A separate Finnish study also found that women who used hair dye were more likely to develop breast cancer.

But if you color your hair regularly, don’t panic! Studies still haven’t determined whether hair dye products can directly cause breast cancer; other factors might influence the connection, too. 'It might be, for example, that women who use hair dyes also use other cosmetics more than women who reported never using hair dyes,' Sanna Heikkinen of the Finnish Cancer Registry said.

Worried about your own risk? The best way to protect yourself is to regularly schedule mammograms and conduct self-exams frequently, doctors say.