Hair Conditioning
CYSTINE
Safety score · 0–100
Good
Derived from EU CosIng regulatory status, PubChem hazard data and published research. How we score.
About
A natural amino acid (two cysteines linked by a disulfide bond) — a building block of keratin. Excellent safety record at cosmetic levels.
Function
Skin benefits
- Sulfur-containing amino acid
- Hair structure component
- Skin/hair conditioning
Known concerns
- No significant concerns at cosmetic concentrations
- Mild rare allergy possible
References
EU CosIng database
European Commission cosmetic ingredient registry — regulatory status, restrictions, authorised functions.
Related hair conditionings
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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.