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Active Ingredient

BUTYROLACTONETHIOL

CAS 14032-62-3
40

Safety score · 0–100

Moderate

Derived from EU CosIng regulatory status, PubChem hazard data and published research. How we score.

A thiol-bearing butyrolactone used to reduce hair disulfide bonds during perms. Functions like thioglycolate but with a stronger odour and similar irritation potential; rinse-off use only.

Function

HAIR WAVING OR STRAIGHTENINGREDUCING

Skin benefits

  • Reducing agent for permanent hair waving
  • Disulfide-bond reshaping in hair
  • Alternative to ammonium thioglycolate

Known concerns

  • Strong sulfur odour and irritation potential
  • Skin and eye irritation with prolonged contact
  • Limited toxicological dataset versus mainstream thiols

References

EU

EU CosIng database

European Commission cosmetic ingredient registry: regulatory status, restrictions, authorised functions.

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SULINDAC
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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.