Anses sounds the alarm: several cases of acute renal failure caused by “Brazilian straightening” hair products

Glyoxylic acid, when it enters the bloodstream via the scalp, can transform into calcium oxalate crystals. Unsplash – illustration – Milad Fakurian

Health authorities are warning this Wednesday, October 16, 2024 about “Brazilian straightening” products containing glyoxylic acid. This ingredient can cause acute kidney failure by passing into the bloodstream via the scalp.

The use of “Brazilian straightening” hair products containing glyoxylic acid, a cosmetic ingredient considered “potentially toxic”, is not recommended. These products could cause acute renal failure, according to an alert issued Wednesday by health authorities, who are investigating several cases.

This alert follows the identification, by the French National Agency for Food Safety (ANSES), of “four cases of acute renal failure linked to the use of various hair products containing glyoxylic acid” in France, states a press release.

Among these cases, “three people poisoned between January and August 2024 were able to recover thanks to a treatment”, while “the fourth is still hospitalized”, according to Anses. These incidents occurred after the application of a smoothing product in a hair salon. An expert assessment is underway on the renal toxicity of glyoxylic acid when applied to the hair.

When glyoxylic acid enters the bloodstream via the scalp, it can transform into calcium oxalate crystals, causing kidney damage, explains Dr. Juliette Bloch, Director of Health Alerts and Monitoring at ANSES.

Raising awareness among the public and professionals about this potential toxicity

“It is likely that other cases have gone unnoticed: some people eliminate the crystals naturally without developing symptoms, or do not make the connection with the use of the product even in the case of kidney failure diagnosed quickly,” she adds. The aim of this alert is to raise awareness among the public and professionals about this potential toxicity.