Restricted substance
HYDROXYTRYPTOPHAN
Safety score · 0–100
Caution
Derived from EU CosIng regulatory status, PubChem hazard data and published research. How we score.
5-Hydroxytryptophan is a serotonin precursor used as a dietary supplement, not a routine cosmetic ingredient. Its GHS toxicity profile and pharmacological activity argue against any leave on skincare use.
Skin benefits
- Serotonin precursor amino acid studied in nutritional supplements
- Theoretical antioxidant activity in vitro
- Listed for transparency only in cosmetic ingredient catalogs
- No clearly established topical cosmetic benefit
Known concerns
- PubChem GHS classification labels it toxic if swallowed
- Serious eye irritation and harmful if inhaled per GHS
- Acts pharmacologically on serotonin system if absorbed
- No safe use level established for cosmetic skin products
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, so always read the physical product label and consult a healthcare professional for personal concerns.