Skip to content
emollient · solvent

Cyclopentasiloxane

Commonly feared, low concern·Strong evidence

A lightweight, volatile silicone that gives serums and primers their silky slip and quick-evaporating finish. Human safety data are reassuring; the EU restriction on this ingredient in rinse-off products is about environmental persistence in waterways, not skin safety.

The myth vs the evidence

Myth: cyclopentasiloxane is "banned" because it is dangerous to skin. Evidence: the EU capped D5 (and D4) at 0.1% in wash-off cosmetics under REACH because these silicones persist and bioaccumulate in aquatic environments, a separate concern from topical safety. The SCCS did not find it unsafe for skin contact at cosmetic levels, and it remains permitted in leave-on products.

Worth knowing

  • Restricted in the EU

EU limits cyclopentasiloxane (D5) to a maximum of 0.1% in rinse-off cosmetic products for environmental reasons under REACH; leave-on use is not restricted on safety grounds.

Questions

Is cyclopentasiloxane banned because it is dangerous to skin?
No. Cyclopentasiloxane (D5) is restricted in rinse-off products in the EU, but the concern is environmental persistence in waterways, not skin safety. Safety assessments found it acceptable for skin contact at cosmetic levels, and it remains permitted in leave-on products.
I heard D5 silicone is toxic. Is this true?
The published safety evidence does not support that concern. D5 is graded as having reassuring human safety data. The EU restriction you may have heard about applies only to wash-off products and is based on environmental bioaccumulation, not toxicity to skin.

Products with Cyclopentasiloxane

In our guides

References

Cosmetic information for general education, not medical advice. A verdict is a reading of the published evidence, never a guarantee for your skin: any ingredient can irritate someone, so patch test new products and see a professional if you react. Concern is graded on cited evidence, never on hazard-score lists. See how we score.