Chemical hair straighteners are linked to uterine cancer  

Scientists warn

A recent increase in rare and aggressive uterine cancers in the US, particularly among women of color, has led to a study concluding that hair straightening chemicals are partly to blame.

For 11 years the researchers followed 33,947 adult women, of whom 378 developed uterine cancer. They found that those who used chemical straightening products more than four times a year were more than 155% more likely to develop uterine cancer than those who had never used them.

Those who did not use such products had a 1.64% chance of developing uterine cancer by the age of 70, while the rate rose to 4.05% for those who used straightening chemical products.

In the same study, hair dyes were not linked to uterine cancer.

This is the first epidemiological evidence of a link between the use of straightening products and uterine cancer – National Institute of Environmental Health Sciences

The troubling results add to other studies investigating widely used chemicals that disrupt our endocrine system, the chemical messengers in our bodies that connect hormones to our organs. Hormones like estrogen have been linked to uterine cancer in the past, and many hair products mimic these natural hormones to bind to their receptors.

A 2018 survey found endocrine-disrupting chemicals in 18 hair products, with 84% of them not even listed in the product formulation, while 11 of them contained chemicals banned by European law.

A 2019 study found that permanent dyes and straightening chemicals were associated with a higher risk of breast and ovarian cancer, especially among women of color who used these products more often.

The human skull absorbs more chemicals, which cannot enter the human body from other areas of the skin, such as the palms or the abdomen.

The research was published in the Journal of the National Cancer Institute .