Campaigners are calling on the cosmetics company L’Oréal to withdraw its hair-straightening products that are largely used by black women after research linked it to an increased risk of cancer.

In an open letter, coordinated by the UK feminist group Level Up, campaigners also ask the company to invest in research on the long-term use of chemical relaxers, which make hair easier to straighten.

The letter is signed by a coalition of politicians, campaigners and professionals, including the Labour MP Dawn Butler; Mandu Reid, the leader of the Women’s Equality party; the peer Lola Young; Andrea Simon, the director of the End Violence Against Women Coalition; the author Reni Eddo-Lodge; the actor Lolly Adefope; and the leading #MeToo campaigner Marai Larasi.

The campaign follows scientific research that claims to show an association between the use of chemical hair straighteners containing lye, also known as sodium hydroxide or caustic soda, and cancer. A 2022 study by the US National Institutes of Health found that women who used such products several times a year were more than twice as likely to develop uterine cancer.

A 2021 study published in Oxford University’s Carcinogenesis Journal, found links between heavy use of lye-containing relaxers and breast cancer, though it found little evidence to support a link between overall hair relaxer use and the risk of breast cancer. However, the researchers said the results of studies, including their own, had been inconsistent. They called for further studies to better establish whether there were links between breast cancer and products with and without lye.

L’Oréal denied the claims of a link and said it was confident of the safety of its products.

In February, nearly 60 lawsuits claiming hair relaxer products sold by L’Oréal and other companies caused cancer, and other health problems were consolidated in a Chicago federal court. The lawsuits allege the companies knew their products contained dangerous chemicals but marketed and sold them anyway.

L’Oréal has said these lawsuits have no legal merit.

Other signatories of the open letter include Leanne Pero, from Black Women Rising; the Labour MP Apsana Begum; the campaigner Lekia Lée; and the feminist activist Dr. Akima Thomas. Eight other Labour MPs signed the petition, including Paulette Hamilton, Ian Lavery and Valerie Vaz.

Ikamara Larasi, a campaigner at Level Up, said: “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.”

Butler said: “I am all too familiar with these hair-relaxing products. It is deeply worrying that not enough is done to inform everyone using these products of the potentially serious damage that may be caused by long-term use.”

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

“L’Oréal upholds the highest standards of safety for all its products. Our products are subject to a rigorous scientific evaluation of their safety by experts who also ensure that we follow strictly all regulations in every market in which we operate.”

The Cosmetic, Toiletry and Perfumery Association, the umbrella organisation that represents cosmetic companies, criticised the US National Institutes of Health study and said the link between hair relaxers and cancer is unfounded.

By Aamna Mohdin

Learn more:

Nearly 60 Hair Relaxer Lawsuits Against L’Oréal, Others Consolidated in Illinois Federal Court

At least 57 lawsuits have been filed in federal courts across the country over the products, which use chemicals to permanently straighten textured hair, court records show.