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Straightening Your Hair Can Cause This Scary Disease, Study Says

Straightening your hair can put you at major risk.

Over the years, hair straightening has been a staple treatment for many. If you've ever dealt with frizzy hair or flyaways, it can be a total lifesaver—especially in the summer. But is it really? According to research led by the National Institute of Environmental Health Sciences (NIEHS), before you book an appointment to get your hair straightened, beware of the uterine cancer risk. Read on to learn how chemicals in hair straightening products can be extremely hazardous to your health.

The study revealed that women who use hair straightening products in excess of four times per year double their risk of developing uterine cancer in comparison to women who don't use hair straightening products. The study incorporated previous research conducted by NIEHS that lasted just under an 11-year period, observing 33,497 women between the ages of 35 to 74. During that time, 378 cases of uterine cancer were detected. The researchers note that there were no links to uterine cancer found with other hair products women in the study used for their hair, such as highlights, bleach, hair dyes, or perms.

Head of the NIEHS Environment and Cancer Epidemiology group and lead author of the new study, Alexandra White, Ph.D. explained, "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%," adding, "This doubling rate is concerning. However, it is important to put this information into context—uterine cancer is a relatively rare type of cancer."

Of all newly diagnosed cancers, 3% is related to uterine cancer. This is the most typical type of cancer found in the female reproductive system, and cases are increasing across the country. In fact, it's estimated that there will be 65,950 new cases diagnosed this year alone. According to Science Daily, "Approximately 60% of the participants who reported using straighteners in the previous year were self-identified Black women." The study did not detect a correlation between race, using a straightener, and uterine cancer, but it did indicate the negative health consequences may be higher for Black women.

Che-Jung Chang, Ph.D., one of the authors of the new study and a research fellow in the NIEHS Epidemiology Branch, explained, "Because Black women use hair straightening or relaxer products more frequently and tend to initiate use at earlier ages than other races and ethnicities, these findings may be even more relevant for them."

Related: The Best Foods To Help Prevent Breast Cancer, Expert Says

What chemicals in straightening treatments are linked to cancer?

close-up woman receiving hair straightening keratin treatment

So, what seems to be the culprit here? The research found that some chemical ingredients detected in straighteners, including formaldehyde, metals, parabens, and bisphenol A, could be contributors to the heightened uterine cancer risk. The chemicals women are exposed to from certain hair product use—like straighteners—may present more of a health risk than other products because of the higher absorption through one's scalp. This can be worsened by burns from the straightener.

White further points out, "To our knowledge this is the first epidemiologic study that examined the relationship between straightener use and uterine cancer. More research is needed to confirm these findings in different populations, to determine if hair products contribute to health disparities in uterine cancer, and to identify the specific chemicals that may be increasing the risk of cancers in women." Prior to this study, the team discovered straightening treatments and permanent hair dye may heighten the risk of ovarian and breast cancers.

Alexa Mellardo
Alexa is the Mind + Body Deputy Editor of Eat This, Not That!, overseeing the M+B channel and delivering compelling fitness, wellness, and self-care topics to readers. Read more about Alexa