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Hair Conditioning

CYSTEIC ACID

CAS 498-40-8 / 13100-82-8 Updated
80

Safety score · 0–100

Good

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

About

The oxidized form of cysteine — a natural sulfonic-acid amino acid that conditions skin and hair. Well tolerated; commonly forms in oxidatively damaged hair and is biologically familiar.

Function

SKIN CONDITIONING

Skin benefits

  • Hair fiber conditioning
  • Skin compatibility
  • Mild pH buffering
  • Endogenous biology

Known concerns

  • Acidic — pH balance required
  • Sparse clinical dossier

References

EU

EU CosIng database

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

Related hair conditionings

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ABYSSINIAN/MEADOWFOAMAMIDOPROPYL PG-DIMONIUM CHLORIDE PHOSPHATE
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ACRYLIC ACID/METHACRYLAMIDOPROPYLTRIMONIUM CHLORIDE COPOLYMER
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AMINOPROPYL PHENYL TRIMETHICONE
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AMODIMETHICONE
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AMODIMETHICONE HYDROXYSTEARATE
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 80
BIS-HYDROXY/METHOXY/METHYL AMODIMETHICONE CROSSPOLYMER
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 80
BIS-PEG-8 PEG-8 DIMETHICONE
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 80
BIS-PHENYLPROPYL DIMETHICONE
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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.