Formaldehyde and hair smoothing: what does science say in 2026?
EU regulations, proven risks, alternatives, and salon ventilation
Formaldehyde is classified as CMR 1B by the EU. Current regulatory threshold: 0.2% free formaldehyde. Validated alternatives: glyoxylic acid and vegetal tannin. NF X 35-102 standard recommends active ventilation in smoothing cabins (≥ 30 m³/h/person).
Contents (5)
What is formaldehyde?
Formaldehyde (CH₂O) is a gas used in some professional hair smoothing treatments to set hair’s hydrogen bonds under the heat of a flat iron. It has been classified as a category 1B carcinogen by the EU since 2014, with exposure requiring monitoring in professional environments.
EU Regulations 2026
EC Regulation 1223/2009 sets the permitted limit of free formaldehyde at a maximum of 0.2% in rinse-off cosmetics. In 2026, several member states (France, Belgium, Netherlands) are tightening enforcement: reinforced salon inspections, mandatory cabin display, certified mechanical ventilation.
Proven Risks
- Short-term ENT and ocular irritation (INRS studies 2019, 2022)
- Skin sensitization (contact dermatitis)
- Statistical association with certain nasopharyngeal cancers in chronic occupational exposure
NIOSH (United States, 2011) studies documented concentrations exceeding OSHA thresholds during the active use of some Brazilian smoothing treatments.
Validated Alternatives
Two formaldehyde-free pathways have emerged:
- Glyoxylic acid: smoothing action through reversible imine bond formation
- Vegetal tannin: action through protein sheathing, lasting 3–4 months
Brands like ULTRALISS (JANNA Coréen, KS Nano Tech, Prime Bio Tanix) are formulated with 0% free formaldehyde.
Salon Ventilation
Even with formaldehyde-free products, standard NF X 35-102 recommends active ventilation in smoothing cabins (air exchange ≥ 30 m³/h/person). Investing in a certified wall extractor protects the team and reassures clients.
Frequently asked questions
Rédaction ULTRALISS
Équipe éditoriale experte
L'équipe éditoriale d'ULTRALISS réunit coiffeurs experts, formateurs et rédacteurs spécialisés dans les soins capillaires professionnels pour cheveux texturés.