Hair straightening products increase the risk of uterine cancer, according to a new study released on Monday.

Women who use these products frequently, more than four times a year, are twice as likely to develop uterine cancer, especially endometrial cancer. This disease should not be confused with cervical cancer.

The study points to the harm of chronic use of substances such as parabens, bisphenol A, metals and formaldehyde. Photo: Markus Liste/Pexels/Disclosure/ND

“We estimate that 1.64% of women who have never used hair straighteners will develop uterine cancer by the age of 70. But for frequent users, that risk increases to 4.05%,” Alexandra White, lead author of this study, said in a statement published in the Journal of the National Cancer Institute.

“A doubling of this figure is worrying,” he added. However, uterine cancer is relatively rare, accounting for about 3% of new cancer cases in the United States.

The study is based on data from 33,500 American women who were followed for nearly 11 years.

Because black women are more likely to use these products and tend to start at an earlier age, “these findings may be of particular interest to them,” said Che-Jung Chang, co-author of the study.

Approximately 60% of women who used hair straightening products in the past year identified themselves as black.

The researchers did not collect information on specific products and brands, but note that some of the chemicals present in these types of products may contribute to an increased risk of cancer: parabens, bisphenol A, metals, or even formaldehyde.

The latter, popularly known as formaldehyde, is used for the so-called Brazilian straightening.

Compared to other categories, hair straightening products can help absorb chemicals from scalp injuries or burns, or from flat irons whose heat breaks down chemicals, the study says.

Other studies have already established a link between straighteners and an increased risk of breast cancer.