Recently, French authorities issued a significant warning regarding the potential health risks associated with hair straightening products that contain glyoxylic acid. The alert was prompted by four documented cases of acute renal failure linked to the application of Brazilian straightening treatments, which occurred between January and August 2024. The affected individuals, aged 28 to 42, reportedly experienced kidney complications after receiving these treatments at hair salons. Fortunately, all four patients recovered following medical intervention in local hospitals.
The National Agency for Food, Environmental and Occupational Health Safety (ANSES), alongside the General Directorate for Competition, Consumer Affairs and Fraud Control (DGCCRF) and the General Directorate for Health (DGS), has recommended that consumers refrain from using products containing glyoxylic acid as a precautionary measure. Glyoxylic acid is commonly used as a formaldehyde substitute in hair care, despite formaldehyde being classified as carcinogenic since 2013.
Dr. Juliette Bloch, director of health alerts at ANSES, explained that when glyoxylic acid enters the bloodstream through the scalp, it can convert into calcium oxalate crystals, which pose a significant threat to kidney health. Dr. Bloch noted that there may be additional unreported cases, as symptoms can sometimes resolve unnoticed if the body eliminates the crystals naturally through urine. This lack of awareness can lead to missed connections between the product usage and subsequent kidney issues.
As a result, hair salons and consumers are advised to avoid these products, and cosmetic retailers are instructed to halt their sales until ANSES completes its ongoing assessment of glyoxylic acid’s renal toxicity, expected by the end of 2024. The agency emphasizes the importance of consulting a healthcare professional immediately if symptoms of kidney failure—such as abdominal or lower back pain, nausea, or vomiting—arise shortly after using such products.
