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Chemical Hair Straighteners and Cancer

Kevin Lombardi, MD MPH

Oct 27, 2023

Which Chemicals in Hair Straighteners Cause Cancer?

Chemical Hair Straighteners and Cancer

Recent medical studies found a connection between the use of chemical hair straighteners and uterine cancer. Certain chemicals in hair relaxers are known carcinogens and disrupt the reproductive systems of women and men.

Which Chemicals in Hair Straighteners Cause Cancer?

Endocrine disrupting chemicals contained in many hair products more than double the risk of developing uterine cancer when used more than four times per year. Although researchers of a 2022 study from the National Institutes of Health didn’t investigate specific brands or ingredients in hair products, they acknowledged that several chemicals commonly found in chemical hair straighteners — including parabens, metals, bisphenol A and formaldehyde — create a higher risk of uterine cancer.

Heat usually activates chemical straightening solutions. When a hair stylist heats the solution, formaldehyde in the products gets released into the air as a gas. The International Agency for Research on Cancer identifies formaldehyde as a human carcinogen based on leukemia and nasopharyngeal studies.

Chemicals Found in Hair Straighteners and Associated with Cancer

  • Bisphenol A

  • Formaldehyde (methylene glycol and formalin)

  • Metals

  • Parabens

Another recent NIH study also examined potential links between hair products and other cancers, particularly those that develop in response to hormones, including ovarian cancer, breast cancer and uterine cancer. Medical professionals raised concerns about the possibility of ingredients in hair relaxers getting absorbed through the scalp and having estrogen-like properties in the body.

Parabens, a group of chemicals often used as preservatives in cosmetics products, have a high endocrine-disruption capacity. They disturb hormones and reproductive systems of men and women and increase the risk of cancer.

Bisphenol A caninteract with estrogen receptors, a likely reason why receptors can trigger the development of multiple cancers. Exposure to heavy metals, including cadmium, arsenic, nickel and chromium, all classified as group 1 carcinogens, can induce cell damage and other changes that result in an increased risk of cancer.

Cancers Associated With Chemical Hair Straighteners

Chemical hair straighteners and other hair products are associated with hormone-sensitive cancers, including uterine, breast and ovarian cancers. Researchers discovered that some chemicals in chemical straighteners, including parabens and phthalates, get absorbed through the skin and disrupt the endocrine system. Another common ingredient, formaldehyde, is a known human carcinogen. Studies show the toxic chemical damages human DNA and is linked to myeloid leukemia.

Findings from the 2022 NIH study provided the first epidemiological evidence of the link between the use of chemical hair straightening treatments and uterine cancer. Women who applied chemical straighteners more than four times a year had more than double the risk of uterine cancer.

The previous study showed that women who used chemical straighteners had a higher risk of developing breast cancer than those who didn’t — and a 30% increased breast cancer risk if they used them every five to eight weeks. A collection of medical studies published over the past 10 years also associate the use of chemical hair straighteners with uterine fibroids and endometriosis.

Researchers from the 2022 study that connect chemical hair straightening treatments to cancer didn’t collect information on specific brands and ingredients in chemical hair straighteners. However, they listed parabens, phthalates (including bisphenol A), formaldehyde and metals, which are common in chemical hair straighteners, as chemicals that can cause cancer.

Chemicals in hair relaxers affect people in different ways, depending on the chemical and the volume of exposure to it. Health problems can include nose and throat irritation, difficulty breathing, difficult swallowing, red or burning skin and central nervous system issues such as nausea, headaches and dizziness.

Consumers say some cosmetics brands marketed and distributed products that increased the risk of uterine cancer, breast cancer and ovarian cancer, among other health issues.

Hair Straightening Brands Linked to Cancer Litigation

  • Dark and Lovely

  • Just for Me

  • L’Oreal

  • Motions

  • Namaste

  • Olive Oil Girls

  • Optimum

  • Soft & Beautiful

  • Strength of Nature Global LLC

  • TCB Naturals

Scientists say they need more data to replicate study results and draw more definitive conclusions.

Reducing Your Risk of Exposure

The easiest way to reduce your risk of exposure to chemical hair straighteners is not to use them. One way to straighten curly hair is to use a flatiron, although overusing the heated iron will damage your hair. You can also heat style your hair with serums that don’t have harsh chemicals, although results last only a couple of days. There are also various online recipes for natural hair straighteners made with oil, coconut milk and fruits that could help straighten curly hair.

Professional stylists are more at risk of negative effects from chemical straighteners because they work with them so often. They must be extra cautious about how often they use these straighteners on clients.

What to Do If You’ve Been Diagnosed With Cancer

If you use chemical hair straighteners regularly and are diagnosed with cancer, work with your doctor and other specialists to develop a treatment plan. Options depend on the type and stage of the cancer, your age, health, potential side effects and preference of treatment. Surgery, chemotherapy, radiation therapy and hormonal therapy are among the usual treatment options. Immunotherapy is also an option for aggressive forms of uterine cancer and some types of breast cancer.

Although endometriosis has no known cure, some treatment options address related pain and infertility. They include hormonal therapy, pain medication and surgery. Many women who develop fibroids show few to no symptoms and may not need treatment. If you have symptoms or your doctor deems it necessary to treat your fibroids, available treatments include surgery and newer options such as radiofrequency ablation and anti-hormonal drugs.

Consumers started filing lawsuits after publication of the 2022 NIH study showing an increased risk of uterine cancer with the use of chemical straighteners. Plaintiffs claim hair straightener manufacturers knew, or should have known, that their products were defective and dangerous because they contain toxic endocrine-disrupting chemicals and carcinogens.

Some consumers also claim that manufacturers marketed hair straighteners to Black women, whose naturally curly hair made them potential buyers. In fact, 60% of the participants in the 2022 study who reported using chemical hair straighteners were Black women, leading researchers to conclude that the exposure burden is higher among that demographic.

If you have any of the listed health conditions and applied chemical hair straighteners regularly over the years, you may be eligible to file a chemical hair straightener lawsuit to recover medical expenses and lost wages. Speak to an attorney about your diagnosis and your history with hair straighteners.

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