Is Hair Dye Safe?

#EcoAdvice from our expert

Dear Dr. Donley,

I’ve been dyeing my hair for decades now, mostly just in the course of habit. But during this pandemic, I’ve been slowly watching my roots grow out. And for the first time, I’m starting to question whether I want to keep doing it. What are the personal and environmental impacts of using hair dye?


Not Dye-ing for a Long Answer, Just the Highlights

Dear Dye Hard,

I’ve heard many a proclamation that we’ve entered the hair dye-hoarding phase of the COVID-19 pandemic. Folks who have successfully hidden their true hair color for years are being outed by those pesky little roots, triggering a run on store-bought hair dye.

My only foray into hair dyeing was in high school, when I inexplicably thought it would be a good idea to put lemon juice in my hair and bake in the sun all day to get that “natural, sun-bleached blond” look. As it turns out, my dark hair and lemon juice make the worst shade of orange you can imagine. As an overly dramatic teen cloaked in a thick layer of attitude, my life was RUINED!

But many people have better experiences with hair dyeing. Roughly 64 million people in the United States, about 20% of the population, used hair-coloring products in the past year.

While some temporary hair dyes, like lemon juice and henna, are natural and pretty benign, the more popular permanent hair dyes contain a host of harmful ingredients that have escaped regulatory oversight and are increasingly tied to human health harms. Most contain ammonia, which facilitates infusion of the chemicals that produce color. Hydrogen peroxide is often used to bleach natural hair color and as an activator of the coal-tar-derived paraphenylenediamine (PPD). PPD by itself will give your hair that beautiful, radiant coal-tar color. To get all the colors of the rainbow, different coupling agents are added that react with PPD to produce a range of hues. An estimated 5,000 chemicals are used in hair products.

Some hair-dye components have been found to cause mammary tumors in mice, while others have been shown to make their way into breast tissue in humans where they react with DNA. Researchers at the National Institutes of Health looked at breast-cancer incidence and hair dye use in 46,000 women and found that women who used hair dye at least once a year had a 9% higher breast cancer risk. However, the racial disparities were striking, with white women who use hair dye having a 7% higher risk and black women who use hair dye having a 45% higher risk. This correlates with the fact that hair products marketed to women of color contain a high number of endocrine disrupting chemicals.

One study found more than two-thirds of hair-dye users reported having a headache after application and about a third reported dizziness and some hair loss. Next time you dye your hair, take some time to check whether your body’s trying to tell you something.

Beyond the personal impacts, hair dyeing can have a significant environmental impact. With the bulk of the 65 million people who dye their hair doing it four to five times per year, and nearly all that hair dye just getting washed down the drain, much of the stuff eventually makes its way to lakes, rivers and streams. Wastewater-treatment facilities are designed to filter out organic materials and are often not equipped to handle the hazardous chemicals present in cosmetic products like hair dye. Virtually none of the chemicals in hair dye have been tested for their impacts on aquatic ecosystems or ability to bioaccumulate up the food chain.

Clearly the choice of whether to dye your hair is complex. If it weren’t, people wouldn’t be smearing antihistamine on their heads and covering themselves with plastic to prevent hair-dye rashes. And the 76% of hair-dye users who believe that hair dying is unsafe, and the 57% who believe that it can cause cancer, would probably not be dying their hair.

Since this pandemic has given you the opportunity for reflection, maybe think about whether you want to be interacting with these chemicals, whether you want to go au naturel, or whether you want to look into more natural dyes. The final choice of whether to dye or not to dye will always be personal, as it was for me back in high school. But the more information you have about the potential costs, the more confident you’ll be that your decision is the right one.

Stay wild and KEEP STAYING HOME,

Dr. Donley

Dr. Nathan Donley is a scientist at the Center for Biological Diversity who answers questions about how environmental toxins affect people, wildlife and the environment. Send him your questions at [email protected]

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