Beauty giant L’Oréal is being urged to remove its hair-straightening products from the market after recent studies found that such products contain carcinogens.

Many of the hair-straightening products are made using lye, also known as caustic soda, which is known to cause uterine cancer among women who use these products several times a year, according to a 2022 study by the US National Institutes of Health.

These products, today used mainly by Black women, can also cause breast cancer. A 25-year-long study of 59,000 Black women conducted by Boston University found that women who used hair products containing lye at least seven times a year for 15 years or longer had a 30% increased chance of developing breast cancer compared to infrequent users.

Findings from these studies have prompted activist groups and politicians to ask L’Oréal to do more research into the long-term effects of its hair-straightening products.

“We should all be able to trust that the products we use on our bodies are safe … As one of the biggest brands in the world, we’re calling on L’Oréal to use their resources and power responsibly and listen to Black women,” said Ikamara Larasi, a campaigner at Level Up.

L’Oréal, however, refutes the various claims made by multiple studies and continues to vouch for the safety of its products.

“Our highest priority is the health, wellness and safety of all our consumers,” a L’Oréal spokesperson said. “We are confident in the safety of our products and believe the recent lawsuits filed against us in the US have no legal merit.”