Cited skincare — every flag names its source, no upsell.
Cy

Cyclopentasiloxane

Cyclopentasiloxane · CyclomethiconeBarrier

Volatile silicone. Provides slip and a smooth finish; evaporates from the skin within minutes.

What it does

Cyclopentasiloxane is a small-molecule silicone that evaporates from the skin after application — it's the silicone behind the 'silky finish' of many makeup primers and moisturizers without leaving residue. Often paired with dimethicone, where the cyclopentasiloxane provides the application slip and dimethicone provides longer-lasting feel. EU regulators have flagged D5 in rinse-off products for environmental persistence; leave-on cosmetic use remains permitted.

The evidence, graded

expert consensusCyclopentasiloxane and related cyclic silicones condition skin and hair. An expert panel found very little of it passes through skin. The data showed no sign that it irritates or sensitises, and no risk of meaningful body-wide exposure from cosmetic use.Johnson 2011 · International journal of toxicology ↗

Graded per the methodology: strong · moderate · emerging · expert consensus. A weak source on a strong claim gets the weaker label.

Also known as

d5, cyclomethicone

Pairs worth knowing

Dimethicone · works together ↗Phenyl Trimethicone · works together ↗

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