Does Coloring Your Gray Raise Cancer Risk?What the National Cancer Institute Says

Coloring gray hair is one of the most common beauty routines after 50. Between 50% and 80% of women in the U.S. have used hair dye.¹ Here is what the National Cancer Institute (NCI)¹ says about the cancer question.

The background

There are three main types of dye: permanent (about 80% of products), semi-permanent and temporary.¹ Some chemicals in older permanent dyes caused cancer, and manufacturers changed formulas in the mid to late 1970s to remove some of them.¹ Whether any chemicals in today’s dyes cause cancer isn’t known.¹

What studies show for personal use

• Overall: an international cancer agency says personal hair dye use is “not classifiable” as a cancer cause, meaning the evidence isn’t clear.¹
• Bladder cancer: a pooled analysis of 17 studies found no increased risk from personal use; findings for permanent dye specifically are mixed.¹
• Non-Hodgkin lymphoma: higher risk showed up in women who started dyeing before 1980, but not after.¹
• Breast cancer: results have been mixed, but some large, more recent studies found higher risk with more exposure to dye.¹ In one U.S. study of women using permanent or dark dyes, risk was about 7% higher among white women and 45% higher among Black women who used dye than among non-users.¹
• Applying permanent dye yourself at home has been linked to higher breast cancer risk than salon application in some studies.¹

For stylists

Hairdressers and barbers with long-term exposure had higher bladder cancer rates in older studies, though a Swedish study found no increased risk in recent decades.¹

Straighteners and relaxers

Some straightening products contain formaldehyde, a known cancer-causing chemical, and studies have linked straightener and relaxer use with some cancers.¹ Our article on hair relaxers and uterine cancer explains that research.

Lowering your exposure

• Consider semi-permanent color or lighter shades, which use different chemistry.¹
• Use gloves, follow timing directions, and rinse well.
• Space out touch-ups. Our guide to habits that damage hair covers timing.
• Embrace your gray if you’d like to. That’s a choice, not a medical requirement.

Our guides to hair dye safety checks, semi-permanent dye and PPD and why hair turns gray cover related decisions.

Hair, Everywhere includes a Hair Check and a monthly Hair Log. Use them to record color type, how often you dye and any scalp reactions. See the book.