A first alert in October: Anses confirms the renal risk linked to the use of glyoxylic acid present in Brazilian straightening

After an initial alert, the National Agency for Health Safety confirms that glyoxylic acid, contained in Brazilian straightening products in particular, is very likely the cause of acute renal failure. It calls for a restriction, or even a ban, of the products concerned.

After an initial alert in October 2024, the French National Agency for Food, Environmental and Occupational Health and Safety (ANSES) confirmed on Thursday, January 23, the renal risk associated with the use of glyoxylic acid. This chemical substance is found in certain hair products, particularly those used to perform Brazilian straightening treatments. Currently, this substance is not subject to any restrictions or regulations.

After the declaration of a first case of acute renal failure linked to the use of a smoothing product, Anses launched investigations into the possible renal toxicity of glyoxylic acid. As early as October, users, hair salon professionals and hair product stores had been alerted to the existence of this risk.

Four new cases reported since October

Since then, four new cases have been reported to the national cosmetovigilance system. Alerted, the doctors treating these patients were able to make the link between acute renal failure without apparent cause and the performance of a Brazilian straightening treatment.

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Glyoxylic acid, being “very probably the cause of acute renal failure”, Anses recommends “to carry out a risk assessment in order to decide, within the framework of the European regulation on cosmetics, on a restriction or even a ban on the use of this substance in hair care products”.It also calls for a reassessment of the safety of all glyoxylic acid derivatives contained in hair straightening products. Pending these measures, the agency recommends that users and professionals avoid using products containing glyoxylic acid.

What is acute renal failure ?

Acute renal failure (ARF) is a transient and reversible kidney dysfunction, i.e. a rapid decrease in the filtration rate of the kidneys. It is caused by hemorrhage, general infection, poisoning or obstruction of the urinary tract. Dialysis can compensate for this dysfunction while the kidneys recover their functions. Symptoms include abdominal or lower back pain, nausea and/or vomiting that occur a few hours after exposure to the product or even during exposure.

Oxalic acid crystals in the kidneys

In this case, the presence of crystals is thought to be the cause of the cases of ARF described. Concretely, this is “linked to the formation of oxalic acid crystals in the renal tubules, crystals induced by the acid absorbed by the scalp and skin during smoothing”, explained the Academy of Medicine in an alert that it had itself formulated in June 2024. And based on a previous study, “this causal link was confirmed by the application to the skin of mice of a smoothing product containing 10% glyoxylic acid, inducing calcium oxalate crystals in urine within 24 hours”.

In the event of the appearance of symptoms, it is necessary to consult a doctor or call a poison control center. Anses encourages consumers and professionals to report any adverse effects observed to the cosmetovigilance system.

Poison control centers near you:

Angers – 02 41 48 21 21 Bordeaux – 05 56 96 40 80 Lille – 08 00 59 59 59 Lyon – 04 72 11 69 11 Marseille – 04 91 75 25 25 Nancy – 03 83 22 50 50 Paris – 01 40 05 48 48 Toulouse – 05 61 77 74 47