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Preservative

POTASSIUM METABISULFITE

CAS 16731-55-8 / 4429-42-9 Updated
55

Safety score · 0–100

Moderate

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

About

A sulfite-based reducing agent and preservative used to stop oxidation and microbial spoilage. Generally tolerated, but can trigger serious reactions in the small share of people who are sulfite-sensitive (often asthmatics).

Function

HAIR WAVING OR STRAIGHTENINGPRESERVATIVEREDUCING

Skin benefits

  • Effective antioxidant and reducing agent
  • Antimicrobial activity against bacteria and fungi
  • Stabilizes color and prevents browning
  • Long history of use as food and cosmetic preservative

Known concerns

  • Sulfite-sensitive individuals (asthmatics) can react severely
  • Potential to release sulfur dioxide gas
  • Skin and respiratory irritation in concentrated forms
  • Subject to labeling requirements as a sulfite

References

EU

EU CosIng database

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

Related preservatives

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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.