Other
CYSTEAMINE
Safety score · 0–100
Fine
Derived from EU CosIng regulatory status, PubChem hazard data and published research. How we score.
About
Cysteamine is a cosmetic ingredient used in product formulations. Exercise caution due to limited available safety data.
Cysteamine (2-aminoethanethiol) is the simplest stable thiol and a natural degradation product of coenzyme A. In cosmetics it is used in hair-waving and hair-relaxing products where its thiol group reacts with keratin disulfide bonds. It has no GHS hazard classification but is known to be a mild skin sensitiser at high concentrations. The EU SCCS has reviewed cysteamine and considers it safe for professional use in hair products at regulated concentrations, though consumer use is more restricted due to exposure concerns.
Skin benefits
- Keratin disulfide bond breaking for hair waving
- Antioxidant properties due to thiol group
Known concerns
- Skin sensitisation potential at high concentrations
- Characteristic mercaptan odour
References
EU CosIng database
European Commission cosmetic ingredient registry — regulatory status, restrictions, authorised functions.
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This profile is for educational purposes and does not constitute medical advice. Regulatory status and scientific understanding evolve — always read the physical product label and consult a healthcare professional for personal concerns.