A dozen years after a federal agency classified formaldehyde as a human carcinogen, the US Food and Drug Administration (FDA) is tentatively scheduled – in April this year – to unveil a proposal to consider banning the chemical in hair-straightening products.
There has been increasing alarm among researchers over the health effects of hair straighteners, products widely used by and heavily marketed to black women, but advocates and scientists say the proposed regulation would do far too little, in addition to being far too late.
“The fact that formaldehyde is still allowed in hair care products is mind-blowing,” said Linda Birnbaum, a former director of the National Institute of Environmental Health Sciences and the National Toxicology Programme. “I don’t know what we’re waiting for.”
Asked why it’s taking so long to get the issue on the FDA’s agenda, Namandjé Bumpus, the regulatory agency’s chief scientist, told KFF Health News: “I think primarily the science has progressed.
“Also,” she added, “the agency is always balancing multiple priorities. It is a priority for us now.”
The FDA’s slow response to concerns about formaldehyde and other hazardous chemicals in hair straighteners partly reflects the agency’s limited powers when it comes to cosmetics and personal-care products, said Lynn Goldman, a former assistant administrator for toxic substances at the Environmental Protection Agency.
Under the law, she said, the FDA must consider all chemical ingredients “innocent until proven guilty”.
Critics say it also points to broader problems. “It’s a clear example of failure in public health protection,” said David Andrews, a senior scientist at the Environmental Working Group, which first petitioned the agency to ban formaldehyde in hair straighteners in 2011 and sued over the issue in 2016.
“The public is still waiting for this response.”
Mounting evidence linking hair straighteners to hormone-driven cancers prompted several politicians last year to urge the regulatory agency to investigate straighteners and relaxers.
The FDA responded by proposing to do what many scientists say the agency should have done years ago – initiate a plan to eventually outlaw chemical straighteners that contain or emit formaldehyde.
Such a ban would be a crucial public health step but doesn’t go nearly far enough, said scientists who study the issue. The elevated risk of breast, ovarian, and uterine cancers that epidemiological studies have recently associated with hair straighteners is possibly due to ingredients other than formaldehyde, they said.
Formaldehyde has been linked to an increased risk of upper respiratory tract cancer and myeloid leukaemia, Bumpus said of the proposed ban.
But Kimberly Bertrand, an associate professor at the Boston University Chobanian & Avedisian School of Medicine, and other scientists said they were unaware of any studies linking formaldehyde to the hormone-driven, or reproductive, cancers that prompted recent calls for the FDA to act.
“It’s hard for me to imagine that removing only formaldehyde will have an impact on the incidence of these reproductive cancers,” said Bertrand, an epidemiologist and lead author on a study published in December, the second linking hair relaxers to an increased risk of uterine cancer.
Hair products targeted to black women contain a host of hazardous chemicals, said Tamarra James-Todd, an associate professor of epidemiology at the Harvard TH Chan School of Public Health who has studied the issue for 20 years.
Studies have shown these ingredients include phthalates, parabens, and other endocrine-disrupting compounds that mimic the body’s hormones and have been linked to cancers as well as early puberty, fibroids, diabetes, and gestational high blood pressure, which is a key contributor to black women’s outsize risk of maternal mortality, James-Todd said.
The first study linking hair relaxers to uterine cancer, published in 2022, found that frequent use of chemical straighteners more than doubled a woman’s risk.
It followed studies showing women who frequently used hair relaxers doubled their ovarian cancer risk and had a 31% higher risk of breast cancer.
Bumpus praised the studies as “scientifically sound” and said she would leave to epidemiologists and others questions about whether straightener ingredients besides formaldehyde might be contributing to an elevated risk of hormone-driven cancers.
She could not offer a timeline for a formaldehyde ban, except to say the agency was scheduled to initiate proceedings in April.
In addition to cosmetics, formaldehyde is found in embalming fluid, medicines, fabric softeners, dishwashing liquid, paints, plywood, and particleboard. It irritates the throat, nose, eyes, and skin.
Study details
Hair relaxer use and risk of uterine cancer in the Black Women's Health Study
Kimberly Bertrand, Lauren Delp, Julie Palmer, et al
Published on PubMed 10 October 2023
Abstract
Background
Chemical hair relaxers, use of which is highly prevalent among Black women in the US, have been inconsistently linked to risk of oestrogen-dependent cancers, such as breast cancer, and other reproductive health conditions. Whether hair relaxer use increases risk of uterine cancer is unknown.
Methods
In the Black Women's Health Study, 44,798 women with an intact uterus who self-identified as Black were followed from 1997, when chemical hair relaxer use was queried, until 2019. Over follow-up, 347 incident uterine cancers were diagnosed. We used multivariable Cox proportional hazards regression models, adjusted for age and other potential confounders, to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for associations of hair relaxer use with risk of uterine cancer.
Results
Compared to women who never used hair relaxers or used them infrequently (<4 years and ≤1-2 times/year), the HR for uterine cancer associated with heavy use (≥15 years and at least 5 times/year) was 1.18 (95% CI: 0.81, 1.71). However, among postmenopausal women, compared to never/light use, the HR for moderate use was 1.60 (95% CI: 1.01, 2.53), the HR for heavy use was 1.64 (1.01, 2.64), and the HR for ≥20 years of use regardless of frequency was 1.71 (1.08, 2.72). Results among premenopausal women were null.
Conclusions
In this large cohort of Black women, long-term use of chemical hair relaxers was associated with increased risk of uterine cancer among postmenopausal women, but not among premenopausal women. These findings suggest that hair relaxer use may be a potentially modifiable risk factor for uterine cancer.
See more from MedicalBrief archives:
Thousands of black women sue over cancer from hair products claims
Uterine cancer risk linked to hair-straightening products – US study
FDA mulls ban on hair-straighteners
Hair products contain dangerous amounts of formaldehyde