Sq
Squalene
SqualeneBarrier
Unsaturated form of squalane. Naturally present in human sebum; oxidizes quickly, so cosmetic use is rare.
What it does
Squalene (with an 'e') is the natural unsaturated form found in human sebum and shark liver. The 'a' version — squalane — is the stable, hydrogenated form used in skincare. Squalene oxidizes within hours of opening and the oxidized form is comedogenic and pro-inflammatory. Squalane is the molecule you actually want; squalene appears in older or poorly-formulated products.
The evidence, graded
moderateSqualene is a major component of human sebum, and its peroxide form is present in the stratum corneum of acne-prone skin. A pilot in vivo study found acne-prone skin carried more squalene, and that peroxidised squalene correlated positively with sebum content and porphyrin intensity.Condrò 2023 · Pharmaceuticals (Basel, Switzerland) ↗
Graded per the methodology: strong · moderate · emerging · expert consensus. A weak source on a strong claim gets the weaker label.
Pairs worth knowing
Browse all 668 ingredients — grouped by what they do, each with whatever evidence we can cite.
This page is public so a shared ingredient card always has its sources behind it — and so you can check them without an account.
Want more like this?
Every evidence-based flag cites its source, Drop tells you when your routine is complete, and it helps you simplify — instead of selling you more. The app launches on iOS and Android in October 2026. Rate my routine works today at /rate — no sign-in.