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POLYSILICONE-4

CAS -
92

Safety score · 0–100

Excellent

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

About

A cyclic siloxane polymer that forms a breathable, water-resistant film on skin and hair, widely used in leave-on cosmetics with an excellent safety profile.

Polysilicone-4 is a homopolymer of 2,4,6,8-tetramethylcyclotetrasiloxane, classified as a silicone polymer with conditioning and film-forming properties. It deposits on skin and hair to provide smoothness, shine, and temporary protection against moisture loss. It is not subject to restriction under EU Regulation 1223/2009, and its high molecular weight prevents significant skin penetration. The cyclic siloxane units are linked into a polymer network that remains on the skin surface.

Skin benefits

  • Provides smooth, silky skin feel
  • Forms protective film that reduces water loss
  • Improves hair manageability and shine
  • Non-greasy emollient

Known concerns

  • Environmental concern: cyclic siloxanes are under review for PBT (persistent, bioaccumulative, toxic) properties by ECHA
  • Low concern for human health at current cosmetic use levels

References

EU

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 — always read the physical product label and consult a healthcare professional for personal concerns.