Q: I dye my hair regularly, but I’ve heard that permanent hair dye can increase the risk of cancer. Should I be worried?
Scientists have been studying the link between hair dye and cancer for decades. Alexandra White, a public health researcher at the National Institute of Environmental Health Sciences, said that while some studies suggest a link, the findings are mixed, making it difficult to provide foolproof advice.
Still, taking a closer look at this research can help you make an informed decision about what’s best for you and your hair type.
what research shows
Dr. David Goldberg, a researcher and dermatologist in New York City, said most of the research on hair dye has focused on its possible link to bladder cancer, especially among those exposed at work to permanent dyes produced before the 1980s. hairdresser. The longer a hairdresser works and the more time they are exposed through the skin or lungs, the more likely they are to develop bladder cancer.
But other studies have not found this increased risk, possibly because manufacturers began producing less toxic formulations after the 1970s.
However, breast cancer does appear to be linked to permanent hair dye, White said. In a 2019 study involving more than 46,000 women, White and her colleagues found that women who used permanent hair dye regularly (every five to eight weeks) had a higher risk of breast cancer than women who did not use hair dye9 %.
That may sound like a big jump, but in reality, “the increase in breast cancer risk is very small” when a woman’s lifetime risk is considered, White said. On average, a woman’s chance of developing breast cancer is about 13%, so a 9% increase in this value only increases her lifetime risk by 1 percentage point, to about 14%.
However, when broken down by race, the risk is much higher for black women, White said. Black women who regularly dye their hair with permanent hair dye have a 60% increased risk of developing breast cancer, increasing their lifetime risk of breast cancer to nearly 21%, compared with about 14% for white women.
Other studies have also shown a link between permanent hair dye and breast cancer risk in black women. It’s unclear what causes these racial and ethnic disparities, said Dr. Nada Elbuluk, associate professor of dermatology at the Keck School of Medicine of USC.
One possibility is that other hair care products popular among black women, such as chemical straighteners, straighteners and leave-in oils, may also play a role. But more research is needed.
different types of dyes
Goldberg said the findings may be mixed because the chemical combinations used in hair dyes can vary widely between products, and they have changed over the years. This makes it impossible to generalize about all hair dyes.
White said that unlike pharmaceuticals, hair care products are not strictly regulated. Manufacturers are not required to prove that their products are safe before selling them, and because their formulas are often proprietary, it can be difficult to know what’s in them.
However, one finding was fairly consistent. Temporary and semi-permanent hair dyes wash out over time and appear to be safer than permanent hair dyes, which can cause lasting chemical changes in the hair shaft.
White said knowing which specific chemicals may contribute to increased cancer risk is a challenge. But research shows that aromatic amines and phenols in permanent hair dyes can cause cancer.
A safer strategy
Since there are no studies proving that hair dye itself causes cancer, it’s up to you to decide whether you want to continue dyeing your hair, taking into account any other potential risk factors you may have, Elbruck says.
If you want to play it safe, consider these strategies:
Reduce the number of hair dyes. While it’s not certain that the more you dye your hair, the greater your risk of breast cancer, “a good prevention rule is to use it less often,” White says.
Avoid permanent hair dyes during pregnancy. It’s not known for certain whether cancer-causing chemicals in hair dyes increase the long-term risk of cancer in a developing fetus, but there is evidence that these chemicals may increase the chance of developmental problems. Therefore, it’s best for pregnant women to avoid hair dye “for at least the first three months of pregnancy,” Goldberg says.
Follow coloring instructions carefully. When dyeing at home, wear protective gloves, apply the dye in a well-ventilated room, do not leave the dye on your head longer than the instructions indicate, and rinse your scalp thoroughly when finished. This should help minimize the absorption of chemicals and reduce the risk of skin irritation.
Try using dyes with milder ingredients. Unlike permanent hair dyes, semi-permanent and temporary hair dyes contain chemicals that are less harsh and do not penetrate the hair shaft. Safer: Try plant-based dyes like henna, Goldberg says. Although these dyes don’t have the staying power of permanent dyes, they don’t appear to be linked to cancer and are less likely to irritate the skin than chemical dyes.