France’s Food, Environment and Labor Security Agency has issued a warning that Brazilian hair straightening products contain glyoxylic acid, which can cause kidney failure. The product is also used in beauty salons in Morocco, raising concerns about the scope of control and the perception of risks.
Since 2024, four cases of kidney damage related to these products have been recorded in France. The General Directorate of Health and the Anti-Fraud Agency advise against its use. “Be wary of Brazilian hair straightening products,” the agency said. A French scientific study found that glyoxylic acid in these hair products can cause kidney damage.
Dr. Juliet Block, the agency’s director of warnings, said glyoxylic acid can enter the bloodstream and form crystals in the kidneys, disrupting their function. Drinking plenty of water will dissolve and eliminate these crystals and restore normal kidney function.
Although there are no complications in most cases, it is important to consult your doctor immediately if you feel fatigued after these hair treatments. If you notice symptoms such as nausea, abdominal pain, or back pain within a few hours of using a Brazilian product, seek medical attention and inform your doctor or contact a poison control center.
The agency issued a Europe-wide warning because the European Union has the power to ban the use of glyoxylic acid in cosmetics. This substance is also found in some hair masks and color preserving shampoos.
