The whispers about permanent hair dye increasing the risk of cancer may seem like they’re growing louder, but scientists have been looking into the association for decades. And while some research suggests a link, the findings, overall, are mixed.
Still, there’s enough there to warrant a closer look. It could help you make an informed decision about what’s best for you.
What the research suggests
Much of the research on hair dye has focused on its possible link to bladder cancer, particularly among hairstylists exposed at work to permanent dyes made before the 1980s. Some studies found the longer they worked and were exposed through their lungs or skin, the more likely they were to develop bladder cancer. But other studies did not find this increased risk.
However, there does seem to be an association between permanent hair dye and breast cancer. A 2019 study involving more than 46,000 women found that those who used permanent hair dye frequently (every five to eight weeks) had a 9% higher risk of developing breast cancer than those who didn’t use hair dye.
While that may sound significant, it’s actually a relatively small increase in breast cancer risk when it’s put in the context of a woman’s lifetime risk, according to one of the researchers involved in the study. On average, a woman’s breast cancer risk is about 13%, so a 9% increase of that value raises her lifetime risk only to about 14%.
But when broken down by race, the risk for Black women was significantly higher. Black women who colored their hair frequently with permanent dye had a 60% increase in breast cancer risk, raising their lifetime risk to nearly 21% — compared to about 14% for white women.
Other studies have also shown this link between breast cancer risk in Black women and permanent hair dye. It’s unclear, though, what may be driving these racial and ethnic differences. One possibility may be that other hair products popular among Black women, such as chemical hair straighteners and relaxers, may also play a part. But more research is needed.
The chemical combinations used in hair dyes can vary widely between different products, and they’ve evolved over the years, which could be why study findings are mixed.
Hair products are also not strictly regulated. Manufacturers don’t need to prove they’re safe before sale. And because formulations are often proprietary, it can be challenging to know what’s in them.
That said, one finding has been pretty consistent: Temporary and semi-permanent hair dyes, which eventually wash out, seem to be safer than permanent dyes, which cause lasting chemical changes to the hair shaft.
Researchers can’t say with certainty which chemicals could be causing the increases in cancer risk, but the studies suggest that aromatic amines and phenols, found in permanent dyes, have carcinogenic effects.
A safer strategy
Since no studies have proven that hair dye itself causes cancer, it’s up to you to decide if you want to continue coloring your hair. If you do, here are some safer ways to go about it:
Color your hair less frequently. Though it hasn’t been shown definitively that the more you color your hair, the greater your breast cancer risk, coloring your hair less frequently is a sound precautionary practice.
Avoid permanent hair dye during pregnancy. There’s evidence that carcinogenic chemicals in hair dye may increase the chances of developmental problems. Researchers are less certain that the chemicals may increase a fetus’s risk of cancer long term.
Follow the instructions to the letter.
If you’re dyeing at home, wear protective gloves, apply the dye in a well-ventilated room, don’t leave it on your head for longer that the instructions indicate, and rinse your scalp thoroughly when you’re done. This should help lower the risk of skin irritation and minimize your absorption of chemicals.
Look for gentler ingredients.
Plant-based dyes, like henna, don’t have the staying power of permanent dyes, but they don’t appear to be linked to cancer and are less likely than chemical dyes to irritate the skin.
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