Well-Being Prevention & Cures

Frequent chemical hair straightening may raise uterine cancer risk, particularly among Black women

Individuals who used hair straightening products at least four times in the previous year were more than twice as likely to develop uterine cancer.

Story at a glance


  • Although uterine cancer is a relatively rare disease, U.S. incidence rates have increased in recent years.

  • Data show non-Hispanic Black women are at a heightened risk of aggressive forms of the cancer and tend to have poor survival rates.

  • Previous research detailed an association between permanent hair dyes and straighteners with higher rates of breast and ovarian cancer.

Women who use hair-straightening chemicals are at an increased risk of uterine cancer compared with those who do not use the chemicals, according to new findings of the Sister Study, run by the National Institutes of Health. 

Because Black women are more likely to use chemical hair-straightening products, the risk of uterine cancer may be greater in this population, researchers said.

Data showed women who used the straightening products more than four times in the previous year were more than twice as likely to develop uterine cancer. 

No associations between uterine cancer and use of hair dyes, bleach, highlights or perms were found.

The study included more than 33,000 women between the ages of 35 and 74. During a follow-up period of nearly 11 years, 378 cases of uterine cancer were diagnosed.


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Uterine cancer is the most common cancer of the female reproductive system and rates have been rising among American women in recent years. According to NIH data, non-Hispanic Black women tend to have higher incidences of aggressive uterine cancer subtypes and poor survival rates. 

“We estimated that 1.64% of women who never used hair straighteners would go on to develop uterine cancer by the age of 70; but for frequent users, that risk goes up to 4.05%,” said lead study author Alexandra White in a release. “This doubling rate is concerning. However, it is important to put this information into context – uterine cancer is a relatively rare type of cancer.”

In the United States, uterine cancer accounts for just 3.4 percent of all new cancer cases.

The majority of women who reported using the straightening products in the previous year self-identified as Black women. Black women also tend to begin using the products at an earlier age than other races or ethnicities, authors added.

Previous research has shown a link between permanent hair dyes and straighteners and increased breast and ovarian cancer risk.

Although the current study did not investigate specific brands or ingredients used, researchers noted several chemicals found in straighteners, like formaldehyde, metals and parabens, could contribute to the increased risk. 

Use of the chemicals in straightening products is particularly concerning, because they absorb more quickly into the scalp. Burns and lesions caused by straighteners could exacerbate this process.

Future research can help determine whether use of hair products contribute to cancer disparity rates and help identify specific harmful chemicals, authors concluded.


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