UPDATE (February 8, 2023, 2:02 P.M. ET): Almost 60 lawsuits against hair relaxer manufacturers are now being consolidated in a Chicago federal court. Allure investigated how concerned we should be about the safety of chemical hair relaxers and straighteners, which one study linked to uterine cancer.
It was in the wake of this study that lawsuits started to be brought against makers of hair relaxers, including L’Oréal. The beauty behemoth issued a statement online, saying it is “confident in the safety of our products and believe the recent lawsuits filed against us have no legal merit.” Our feeds were flooded with headlines like "Frequent Hair Straightener Use Doubles Uterine Cancer Risk" and "Chemical Hair Straighteners 'May Cause' Uterine Cancer.” We talked to three experts, including gynecologic oncologists and the study's lead author.
First, background: The study followed over 33,000 women for nearly 11 years, during which 378 cases of uterine cancer were diagnosed, and indicated an 80-percent increase in risk among women who've used relaxer at least once in the past year. Frequent users of relaxers, defined as those who used chemical straighteners or relaxers more than four times in the past year, were more than twice as likely to develop uterine cancer compared to those who did not use relaxers at all — a jump in their estimated risk of developing uterine cancer by age 70 from 1.64 percent to 4.05 percent.
Meet the Experts:
- Susan Modesitt, MD, the director of the gynecologic oncology division at Emory University's Winship Cancer Institute and editor-in-chief of Gynecologic Oncology Reports
- Alexandra White, PhD, an epidemiologist at the U.S. National Institute of Environmental Health Safety
- Ursula Matulonis, MD, the chief of the gynecologic oncology division at the Dana-Farber Cancer Institute in Boston, MA.
The numbers are scary, but it helps to put these findings into context. While the study data are statistically significant, they present what's ultimately "a small attributable — or extra — risk," says Susan Modesitt, MD, the director of the gynecologic oncology division at Emory University's Winship Cancer Institute and editor-in-chief of Gynecologic Oncology Reports. "People just hear 80-percent increased risk and panic, but it's 80 percent of a really tiny risk." In other words, your entire risk isn't 80 percent; it's 80 percent of that 1.64 percent among those who've never used relaxers — an increase of 1.18 percent, which, she says, is still pretty small.
And it's important to keep in mind that "chemical hair products are just one of many factors that may influence a woman’s chances of getting uterine cancer," says Alexandra White, PhD, an epidemiologist at the U.S. National Institute of Environmental Health Safety and the study's lead author. "More research is needed before firm recommendations can be made." Things like weight and a sedentary lifestyle play a much larger role, for reasons we'll get into below.
That doesn't mean you should ignore the findings entirely, though. While uterine cancer is relatively rare, with 60,000 cases diagnosed annually, that number is rising each year, says Ursula Matulonis, MD, the chief of the gynecologic oncology division at the Dana-Farber Cancer Institute in Boston, MA. "One thought has been that our population is more obese and that the body mass index of women has increased in the United States," she says. Plus, its survival rate is only getting worse, possibly from a rise in more aggressive types of uterine cancer.
To complicate matters, there's a huge disparity in the survival rate for endometrial cancer (which occurs in the endometrial lining of the uterus, and is the most common type of uterine cancer). "Black women have a higher risk of developing endometrial cancer — and also have a worse survival rate compared to white women," Dr. Matulonis says. "It hasn't been fully explained why that's happening, but it's definitely being observed." That's incredibly discouraging, not only because Black women already face implicit bias in their medical care, but also because they tend to use relaxers more often and beginning at an earlier age than others, too.
While this new info may have been a shock to many, the correlation between the frequency of hair relaxer use and uterine cancer risk didn’t come as a huge surprise to experts; in fact, previous research has established a relationship between relaxers and hormonally mediated cancers, such as breast and ovarian cancers and uterine fibroids (typically benign growths that develop in the uterine wall).
And for this study, too, hormonal disruption seems to be behind the increase in risk. "Hair products, such as dye and chemical straighteners, contain a number of different chemicals that may act as carcinogens or endocrine disruptors [molecules that mimic or mess with hormonal function] — and thus may be important for cancer risk," says Dr. White. "Straighteners in particular have been found to include chemicals such as phthalates, parabens, cyclosiloxanes [a type of silicone, used as a solvent, that have also been classified as endocrine disruptors], and metals [like nickel and cobalt, which can at certain levels and in some compounds likely become carcinogenic] and may release formaldehyde when heated."
The type of uterine cancer that commonly arose in the study supports the theory that hormonal disruption is behind the increased risk. "Most of them were endometrioid [tumors], which is interesting because that is the more common subtype of endometrial cancer — and is driven by hormonal factors," Dr. Matulonis says.
If you really want to reduce your risk of uterine cancer, there are other factors that have a much greater impact on uterine cancer than relaxers. Here, preventative measures you can take from the experts.
Consider cutting back
If you currently use a relaxer more than four times a year, consider limiting it to two or three times a year. "We did observe in our study that less frequent use was less strongly associated with risk, so decreasing the frequency of use may be one potential approach," says Dr. White.
Tweak your lifestyle
Relatively speaking, a relaxer's impact is minimal. "If you look at the really big risk factors for endometrial cancer, 50 to 60 percent is directly linked to obesity and lack of physical activity," says Dr. Modesitt. (Adipose tissue, a.k.a. fat, turns the body's natural testosterone into estrogen, which can trigger the growth of hormone-responsive tissues, like that of the breast and uterus — creating more opportunity for a genetic mutation that could cause cancer as well as cancer growth.)
Speaking of physical activity: Even going for more walks may help blunt your risk. While the study didn’t link uterine cancer with hair straighteners and body mass index, "it did see an association with a higher risk of uterine cancer with the use of hair straighteners and lower physical activity," says Dr. Matulonis.
Know the symptoms
There's currently no way to screen for uterine cancer, so it's essential to know what the symptoms are, especially if you think you may be at a higher risk due to genetics or your lifestyle. It usually presents through vaginal spotting in postmenopausal women, while "in women who are still menstruating, it's heavier bleeding or bleeding between periods," Dr. Matulonis. Occasionally, it can be picked up on a Pap smear. If that happens, your doctor may order an endometrial biopsy or a transvaginal ultrasound to scope things out. But ultimately, it's up to you to keep an eye out and visit your ob-gyn if you notice any irregular (for you!) bleeding.
You can read more about relaxers here:
- Chemical Hair-Straightening Products May Pose Higher Risk of Uterine Cancer
- Why Some Black Women Are Going Back to Relaxers
- Three Women Open Up About Embracing Their Natural Hair & Leaving Relaxers Behind
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