St
Stearic Acid
Stearic AcidBarrier
18-carbon fatty acid. Cream thickener; also one of the natural fatty acids in skin barrier lipids.
What it does
Stearic acid is both a workhorse cosmetic thickener (often combined with triethanolamine to form a self-emulsifying base) and a real skin-barrier component. Topical stearic-rich creams help replenish the fatty acid side of the lipid matrix that ceramides and cholesterol round out. Generally well tolerated; common in classic 'cold cream' style emulsions.
The evidence, graded
emergingThe skin's barrier is built from ceramides, cholesterol, and free fatty acids in a roughly 1:1:1 to 3:1:1 ratio. Moisturizers formulated to mimic that ratio support barrier repair more than any one lipid alone.Man 1996 · Journal of Investigative Dermatology ↗
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.