Q. I dye my hair regularly, but I heard that permanent hair dyeing can increase the risk of cancer. Should I worry?
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 some studies suggest a link, but the findings are mixed, making it difficult to provide firm recommendations.
Still, a closer look at this research can help you make an informed decision about what's best for you and your hairstyle.
What the research suggests
According to Dr. David Goldberg, a New York City researcher and dermatologist, much of the research on hair dyes has focused on hair dyes, especially among hairdressers who were exposed at work to permanent hair dyes made before the 1980s. The focus is on a possible link to bladder cancer. The longer a cosmetologist works and the more exposure they are exposed to through their skin and lungs, the more likely they are to develop bladder cancer.
However, other studies have not found such an increased risk, which may be because manufacturers began producing less toxic formulations after the 1970s.
However, White said breast cancer appears to be linked to permanent hair dye. In a 2019 study of more than 46,000 women, White and colleagues found that those who used permanent hair dye more frequently (every 5 to 8 weeks) were less likely to use hair dye than those who never used hair dye. They found a 9% higher risk of breast cancer.
While this may sound like a big leap forward, when compared to a woman's lifetime risk, it's actually “a very small increase in breast cancer risk,” White said. On average, a woman has about a 13% chance of developing breast cancer, so if her value increases by 9%, her lifetime risk increases by just 1 point to about 14%.
But when looked at by race, Black women were at significantly higher risk, White said. Black women who dyed their hair frequently with permanent dye had a 60% increased risk of breast cancer, raising their lifetime risk to nearly 21%, compared to about 14% for white women.
Other studies have also shown an association between permanent hair dye and breast cancer risk in black women. Dr. Nada Elburg, associate professor of dermatology at the Keck School of Medicine at the University of Southern California, said it's unclear what causes these racial and ethnic differences.
One possibility is that other hair products popular among Black women, such as chemical curling irons, relaxers, and leave-in oils, may also be playing a role. However, further research is needed.
different types of dyes
Research results can be mixed because the combination of chemicals used in hair dyes can vary widely from product to product and has evolved over the years, Goldberg said. For this reason, it is impossible to generalize about all hair dyes.
Unlike pharmaceuticals, hair products are not heavily regulated, White said. Manufacturers don't have to prove their products are safe before selling them, and their formulations are often proprietary, so it can be difficult to know what's in them.
However, there is one fairly consistent result. Temporary and semi-permanent hair dyes that wash out over time appear to be safer than permanent hair dyes that cause permanent chemical changes to the hair shaft.
White said it's difficult to know which specific chemicals are causing the increased cancer risk. However, research suggests that aromatic amines and phenols in permanent hair dyes have carcinogenic effects.
A safer strategy
No studies have proven that hair color itself causes cancer, so it's up to you to decide whether to continue coloring your hair, considering other potential risk factors, Elburg said.
If you want to play it safe, consider the following strategies:
Reduce the frequency of dyeing your hair. Although it's not conclusive whether the more you color your hair, the higher your risk of breast cancer, “a good preventive principle is to color your hair less often,” White says.
Avoid permanent hair dye during pregnancy. It is unclear whether carcinogenic chemicals in hair dyes increase the long-term risk of cancer in a developing fetus, but there is evidence that the chemicals may increase the likelihood of developmental problems. There is. Therefore, it's best for pregnant women to avoid using hair dye “at least during the first trimester,” Goldberg said.
Follow the coloring instructions carefully. If dyeing at home, wear protective gloves, apply the dye in a well-ventilated room, do not leave it on your head for longer than the instructions say, and rinse your scalp thoroughly when finished. This minimizes chemical absorption and reduces the risk of dermatitis.
Try dyes with gentler ingredients. Unlike permanent hair dyes, semi-permanent and temporary hair dyes are mild and contain chemicals that do not penetrate the hair shaft. Even safer: Try plant-based dyes like henna, says Goldberg. These dyes don't have the staying power of permanent dyes, but they don't seem to be linked to cancer and are less likely to irritate the skin than chemical dyes.
