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Hair Conditioning

CYSTEINE HCL

CAS 52-89-1 Updated
80

Safety score · 0–100

Good

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

About

An amino acid (cysteine hydrochloride) used in hair products and as an antioxidant precursor. Well-studied with strong food and pharmaceutical safety data.

Skin benefits

  • Sulfur-containing amino acid for hair
  • Antioxidant precursor (glutathione)
  • Used in perm-neutralizing systems

Known concerns

  • Mild irritation at high % in perms
  • Distinct sulfur odor

References

EU

EU CosIng database

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

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AMODIMETHICONE
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AMODIMETHICONE HYDROXYSTEARATE
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BIS-HYDROXY/METHOXY/METHYL AMODIMETHICONE CROSSPOLYMER
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BIS-PEG-8 PEG-8 DIMETHICONE
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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.