Chemical Hair Straightening Products May Be Linked to Uterine Cancer

A new study links frequent chemical hair straightening with uterine cancer, especially among Black women.

          Women may be more hesitant to head to the salon for straightening treatments now due to a recent research study. Everyone likes to look their best. For some people, this includes straightening their hair using chemical hair products. The study was completed by the National Institute of Environmental Health Sciences (NIEHS). Their research, named the Sister Study, was created to help identify risk factors that could cause breast cancer or other health conditions affecting women. They looked at the effects of hair dye, bleach, perms, and straighteners.

          There were over 33,000 women between the age of 35 and 74 who participated in the study. Researchers found that women who frequently use chemical hair straightening products may be at a greater risk of developing uterine cancer. The frequency was defined as using hair straightening products more than four times a year. These women were more than twice as likely to eventually develop uterine cancer when compared to women that don’t use chemical hair straightening products1. There were no links found between cancer and hair dyes.     

          It is crucial to point out that although uterine cancer rates have been rising in the United States, uterine cancer is relatively rare. Approximately 65,950 women every year are diagnosed with uterine cancer. It is the most common cancer of the female reproductive system but it only accounts for around 3% of new cancer diagnoses1.

          Dr. Che-Jung Chang, one of the researchers who worked on the study was quoted as saying, “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.”1 About 60% of the women who participated in the study who frequently used hair straightening chemicals were Black women1.

          Dr. Chandra Jackson, another researcher who contributed to the study told CNN, “Based on the body of the literature in this area, we know that hair products marketed directly to Black children and women have been shown to contain multiple chemicals associated with disrupting hormones, and these products marketed to Black women have also been shown to have harsher chemical formulations. On top of that, we know that Black women tend to use multiple products simultaneously, which could contribute to Black women on average having higher concentrations of these hormone-disrupting chemicals in their system.”2

Gynecologic Oncologist Dr. Troy Gatcliffe, told Healthline “there are myriad ways in which outside chemicals impact the body…the most substantial way is the alterations in the genetic code of cells that can lead to cancerous growth.”3

The research team believes that chemicals such as paragons, bisphenol A, metals, and formaldehyde may be the reason hair straightening products are linked with uterine cancer. These chemicals can alter hormone activity and put people at risk of cancer.

The most common sign of uterine cancer is unusual vaginal bleeding. This could be bleeding in between periods, abnormally heavy periods, frequency periods, or post-menopausal bleeding. Dr. Gatcliffe says, “I encourage women to be their greatest advocates and vocalize if they have any changes in their bleeding pattern or see any bleeding after menopause.”3.


  1. U.S. Department of Health and Human Services. (2022, October 17). Hair straightening chemicals associated with higher uterine cancer risk. National Institutes of Health. Retrieved October 20, 2022, from
  2. Howard, J. (2022, October 18). Hair-straightening chemical products linked to increased uterine cancer risk in new study. CNN. Retrieved October 20, 2022, from
  3. Pattemore, C. (2022, October 19). Hair straightening and uterine cancer: What to know about the risks. Healthline. Retrieved October 25, 2022, from