Arizona has become the first US state to file a lawsuit against L’Oréal over the potential cancer risks posed by chemical hair-straightening products. Attorney General Christine Mace claims that the company failed to warn consumers about a potentially increased risk of uterine and ovarian cancer. The lawsuit has been filed against a backdrop of more than 12,000 active federal cases, whilst L’Oréal denies any link between its products and these diseases.
Briefly about the main points
- Arizona was the first US state to bring a separate legal action against L’Oréal.
- The State is asking the court to impose fines and award compensation, and to order that warnings be included.
- There were 12,129 active cases remaining in the federal MDL 3060 proceedings.
- The NIH has identified a statistical association between the frequent use of hair relaxers and uterine cancer.
- L’Oréal states that its products are safe and that the allegations are not sufficiently substantiated.
What requirements has Arizona set out?
The lawsuit has been brought against the French company L’Oréal SA and its US subsidiary. The state authorities claim that the company has for years been selling chemical products without warning of a possible increased risk of cancer.
Arizona is seeking fines and compensation. It is also asking that the manufacturer be required to include warnings about potential risks should the products in question continue to be sold.
These are chemical relaxers designed to provide long-lasting straightening of textured hair. Among the products mentioned in the case, Reuters cites the brands Dark & Lovely and Optimum.
The federal proceedings have consolidated thousands of claims
As at 1 September 2026, there were 12,129 active cases in the consolidated federal MDL 3060 proceedings. In total, 16,561 cases have already been processed through this docket; they are being heard by the US District Court for the Northern District of Illinois.
The lawsuits have been brought by women who used these products, as well as by the relatives of some of the victims. In addition to L’Oréal, other cosmetics manufacturers, including Revlon, are also named as defendants.
The claimants are seeking reimbursement of medical expenses and economic losses, as well as compensation for physical and emotional suffering. According to Reuters, the first trials in the consolidated case could begin next year.
What the NIH study revealed
One of the grounds for the legal claims is a study by the US National Institutes of Health, published in 2022. The researchers analysed data from nearly 34,000 women aged between 35 and 74, who were followed for an average of around 11 years; during this period, 378 cases of uterine cancer were recorded.
Among participants who had used chemical hair straighteners more than four times in the previous year, the incidence of uterine cancer was approximately 2.55 times higher than among those who had not used them. The estimated risk up to the age of 70 was approximately 4.05% for regular users, compared with 1.64% for women who had never used such products.
The limits of scientific findings and the company’s position
The NIH epidemiological study identified a statistical association, but did not in itself establish a causal link. The researchers did not collect data on specific brands or the exact composition of the products used by the participants.
Scientists They mentioned formaldehyde, parabens, bisphenol A and certain metals as substances previously detected in some hair straighteners. At the same time, they emphasised that further research is needed to identify the components potentially linked to an increased risk.
L’Oréal USA told Reuters that it considers its products to be safe and that the claims are not sufficiently substantiated from a legal or scientific point of view. The company argues that no link has been established between its specific products and the claimants’ illnesses; this issue will be one of the central points in the forthcoming hearings.
