If you dye your hair regularly, you may have wondered about the impact of the chemicals on your health. Recent research has given some reason for concern. A 2019 study by the National Institutes of Health suggests that the chemicals in permanent hair dye and chemical straighteners could increase a woman’s breast cancer risk.
The study found that permanent hair dye use was linked to a 45% higher breast cancer risk in Black women and a 7% higher risk in White women. The use of chemical straighteners was linked to an 18% increase in breast cancer risk.
Before you ditch the dye, however, it’s worth noting that breast cancer is caused by a number of factors and no one thing will guarantee a diagnosis. This article will look at what the research shows about hair dye so that you can make choices that are comfortable for you.
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Early hair dye formulations contained chemicals, including aromatic amines that were found to cause cancer in animals. In the mid- to late-1970s, however, manufacturers changed the components in dye products to eliminate some of these chemicals.
Some hair dye and hair straightening treatments like relaxers contain chemicals called endocrine disruptors that can interfere with your hormones. This hormone disruption is a concern, especially when it comes to hormone-driven cancers like breast, prostate, and ovarian cancers.
Only a minuscule amount of chemicals from hair dye are absorbed through the scalp, and it is not known whether some of the chemicals used in modern hair dyes contain cancer-causing substances.
Hair dye comes in different forms: permanent, semi-permanent, and temporary.
Researchers have been studying the possible link between hair dye and cancer for a long time, but results have been inconsistent.
In a 2019 study, researchers at the National Institutes of Health looked at chemical hair dyes and straighteners to see if they were linked to increased breast cancer risk.
The study tracked 46,709 American women for an average of 8.3 years. All participants had a sister diagnosed with breast cancer but didn’t have breast cancer themselves when they enrolled in the research. After eight years of follow-up, the results showed:
It’s important to note that this study found an association between permanent hair dye and chemical hair straighteners and breast cancer; it is not a direct cause-and-effect relationship. That means using permanent hair dye and chemical straighteners may increase a woman’s risk of breast cancer, but using these products does not directly cause breast cancer.
Researchers didn’t have the information on the chemical components of the products used by the women in the study and don’t give any suggestion as to why these hair products might increase breast cancer risk.
These findings disagree with results from some previous studies in this field. For example, a 2020 study of 117,200 women enrolled in the Nurses’ Health Study showed no positive correlation between the personal use of hair dye and risk of most cancers. Breast cancer risk was only increased in women with a specific subtype of breast cancer who reported using permanent hair dye 200 times or more in their lifetime.
This indicates more research is needed to fully understand the relationship between hair products and breast cancer risk.
The results of the 2019 study showed that hair dye and straightening products impacted Black and White women differently.
According to the researchers, products marketed to Black women have higher concentrations of estrogens and endocrine-disrupting compounds. The color of dye and the frequency of use may be a factor.
It’s important to note that the women in the study already had a higher-than-average risk of breast cancer because they had at least one first-degree relative who had been diagnosed with breast cancer.
What’s more, other research has contradicted this correlation between ethnicity, hair dye, and breast cancer risk, with one recent meta-review of 14 studies finding no association between hair dyes and breast cancer due to race, length of use, or dye color.
This suggests that the relative increased risk for Black women may be due to other variables such as income and access to health care that were unadjusted for in the original study. More research is needed to confirm the results.
The Department of Labor’s Occupational Safety and Health Administration (OSHA) has found that many hair smoothing products contain formaldehyde, formaldehyde dissolved in water (called methylene glycol), or other chemicals that can release formaldehyde during use. Using products that contain these substances can result in worker exposure to unsafe levels of formaldehyde.
Formaldehyde is a colorless, strong-smelling gas that presents a health hazard if workers are exposed. In 2004, the International Agency for Research on Cancer concluded that formaldehyde was a known human carcinogen.
OSHA says that the best way to control exposure to formaldehyde is to use products that do not list formaldehyde, formalin, methylene glycol, or any of the other names for formaldehyde on the label.
For people who want to dye their hair but are concerned about safety, the Food and Drug Administration offers some suggestions:
Some newer hair dye products are vegetable-based. These products may have some drawbacks, such as not being able to change hair color drastically or having the color fade sooner than is seen with permanent dyes, but they may be another option for people concerned about hair dye safety.
While the results from the 2019 study show that hair dye and chemical straightening may increase the risk of breast cancer, the issue is complex because not all hair dyes are the same—they can contain any of thousands of different chemicals. More research is now needed to understand how different compounds found in common hair products could potentially be involved in the development of breast cancer.
While the research on the dangers of hair dye has been mixed, scientists agree that maintaining a healthy weight, keeping physically active, and drinking less alcohol can help lower your cancer risk. Smoking is a known risk factor for cancer, and quitting smoking can improve your health, regardless of whether or not you use hair dyes.
Limited research does suggest permanent hair dye and chemical straighteners may increase a woman’s risk of breast cancer, but using these products does not directly cause breast cancer.
Some research suggests using permanent hair dye and chemical straighteners may increase a woman’s risk of breast cancer, but using these products does not directly cause breast cancer.
It’s generally recommended that you avoid using hair dyes for at least six months after finishing your cancer treatment, to avoid placing your hair under any additional stress and to give your hair follicles and scalp a chance to recover.
It is unclear which hair dyes may increase formaldehyde exposure, but professional keratin hair smoothing treatments can contain formaldehyde or formaldehyde-releasing chemicals. Using these can raise indoor air concentrations of formaldehyde to levels that could be a potential hazard.
Cutting back on hair dye and straightening is potentially one of many things that you could do to reduce your risk for breast cancer. There was no increased risk for women who used semi-permanent or temporary dyes, the kind that eventually washes out with shampooing.