Alert confirmed for glyoxylic acid in hair-straightening products
Glyoxylic acid, a chemical used in hair-straightening products (also known as hair relaxers), can cause acute kidney failure: this was confirmed by ANSES after it examined the available scientific data on its toxicity. The Agency believes that a ruling is needed on restricting or even banning the use of this substance in hair care products. Pending regulatory measures, it recommends avoiding the use of hair-straightening products containing glyoxylic acid. It also urges the companies marketing hair care products containing this substance to re-examine their safety.
Next step towards restriction: a European risk assessment
Glyoxylic acid is a chemical found in certain hair-straightening products, especially those used in the "Brazilian" procedure. There are currently no restrictions on the use of this substance in cosmetic products.
After a first case of acute kidney failure linked to the use of a hair-straightening product was reported to the national cosmetovigilance scheme run by ANSES, the Agency issued an internal request to produce a review of knowledge on the renal toxicity of glyoxylic acid.
In October 2024, without waiting for the expert appraisal to be finalised, ANSES and the health authorities alerted users of such products, as well as hair salon and cosmetics trade professionals, of the possibility of acute kidney failure associated with the application of hair-straightening products containing glyoxylic acid.
After analysing the available scientific data, the Agency now confirms that the glyoxylic acid was very likely responsible for the acute kidney failure. It therefore recommends carrying out a risk assessment in order to issue a ruling, under the European Cosmetics Regulation, on restricting or even banning the use of this substance in hair care products. The Agency also recommends broadening this assessment to include the various glyoxylic acid derivatives used in hair-straightening products.
Raising awareness among workers and the general public
Since the alert was issued in October 2024, four new cases have been reported to the national cosmetovigilance scheme. Knowledge of this risk enabled the doctors treating these patients to make the link between acute kidney failure with no apparent cause and the Brazilian hair-straightening procedure.
ANSES therefore stresses the importance of reminding hairdressing professionals, healthcare professionals and users of this risk of acute kidney failure due to hair-straightening products containing glyoxylic acid. It strongly urges consumers and professionals to report any adverse effects to the cosmetovigilance scheme.
Hairdressing professionals also need to remain vigilant, even though no cases of occupational poisoning have been reported to date.
Encouraging the companies marketing these products to reconsider safety
ANSES's expert appraisal, which focused on the toxicity of the substance, does not identify which hair-straightening products should be avoided. Therefore, without waiting for the findings of the re-examination of the European regulations, the Agency urges the companies marketing hair care products containing glyoxylic acid to re-examine their safety and the suitability of the precautions for use, to ensure that they can be safely used.
Symptoms of kidney failure include abdominal or lower back pain, nausea and/or vomiting occurring within hours of exposure to a product containing glyoxylic acid, or even during use.
If any symptoms develop, consult a doctor as soon as possible or call a poison control centre
Emergency numbers for the poison control centres
ANGERS • +33 (0)2 41 48 21 21
BORDEAUX • +33 (0)5 56 96 40 80
LILLE • +33 (0)8 00 59 59 59
LYON • +33 (0)4 72 11 69 11
MARSEILLE • +33 (0)4 91 75 25 25
NANCY • +33 (0)3 83 22 50 50
PARIS • +33 (0)1 40 05 48 48
TOULOUSE • +33 (0)5 61 77 74 47