Journal of the National Cancer Institute Links Hair Relaxers to Uterine Cancer

Did you know that using hair relaxers could double your risk of developing uterine cancer? A 2022 study by the Journal of the National Cancer Institute (JNCI) has linked many big-name hair relaxer brands to an increased risk of uterine cancer, with frequent users more than twice as likely to develop the disease compared to non-users. The Sister Study, a long-term effort conducted by the National Institutes of Health (NIH), also found that frequent hair relaxer use has been linked to other forms of feminine reproductive cancer, such as ovarian, endometrial, and fallopian tube cancer.

The Sister Study identified several potentially harmful chemicals commonly found in many well-known hair relaxer products that could be contributing to the increased cancer risk. These substances include formaldehyde (a known carcinogen), parabens, phthalates, bisphenol A (BPA), and other complex compounds. Some of these chemicals are classified as endocrine-disrupting chemicals (EDCs), which can interfere with the body’s hormonal balance and lead to a range of health problems. Repeated exposure to EDCs has been associated with an elevated risk of obesity, diabetes, thyroid disorders, breast cancer, ovarian cancer, infertility, and other chronic conditions.

Many cosmetic companies include EDCs in their hair relaxers and other products as fragrance enhancers, but most consumers remain unaware of their presence because these ingredients are usually not disclosed on the product label. The FDA allows manufacturers to conceal certain ingredients under terms like “fragrance,” “parfum,” or “artificial flavors” if they are considered to be part of a “trade secret” formula. Despite the growing evidence linking EDCs to numerous health concerns, the FDA has not yet acknowledged them as a known risk to human health and has not taken steps to regulate their use in consumer products.

Frequent use of products containing EDCs and other cancer-causing substances like formaldehyde has been linked to many different symptoms, ranging from mild to life-threatening:


  • Skin irritation
  • Respiratory problems
  • Drowsiness
  • Headaches
  • Scalp burns
  • Constipation
  • Hormone disruption


  • Vomiting
  • Diarrhea
  • Liver, kidney, or lung damage
  • Cellular toxicity
  • Cell death (known as apoptosis)
  • Impaired fetus development
  • Systemic toxicity

The primary active ingredients in most hair relaxer products, such as sodium hydroxide and guanidine carbonate, are not linked to cancer. However, they can lead to conditions that increase the risk of developing uterine cancer in hair relaxer users. These chemicals, especially when used in high concentrations or left on the scalp for extended periods, can cause skin irritation, burns, and dermatitis. The resulting open wounds on the scalp make it easier for cancerous substances present in some hair relaxers to be absorbed into the body.

Numerous hair relaxer brands have been accused in the ongoing multidistrict litigation (MDL) lawsuit, including products from well-known international companies like L’Oreal and Revlon. The lawsuit considers any hair relaxer formula containing EDCs or carcinogenic substances like formaldehyde to be a potential cancer risk. If you’re concerned about the safety of your hair relaxer, here are some (but not all) of the most common hair relaxers at risk:

  • Dark & Lovely — L’Oréal
  • African Pride — Olive Miracle
  • Supreme No Lye Relaxer —  Ultra Sheen
  • ORS Olive Oil — Namaste, LLC
  • Olive Oil No-Lye Hair Relaxer — TCB Naturals
  • Motions — Strength of Nature Global, LLC
  • Just for Me — Soft & Beautiful
  • Creme of Nature — Revlon

After this study was released, hundreds of women who developed uterine cancer after using hair relaxers joined together to sue major beauty brands. Today, over 8,000 women have filed a hair relaxer claim. If you or an immediate family member developed uterine or ovarian cancer after regularly using a drugstore hair relaxer, see if you qualify to join the lawsuit.