What is Steareth-20?
Steareth-20 is an emulsifier that helps oil and water mix. A common ethoxylated stearyl emulsifier listed in the low-moderate range.
You may see it on labels as Steareth-20, Steareth 20, so it can hide under more than one name in an ingredient list.
Where Steareth-20 shows up
You'll most often find Steareth-20 in almost any lotion or cream, where it keeps the oil and water phases blended. Separately from clogging, its irritancy is rated 0/5 — low, so it's unlikely to sting or sensitise on its own.
Is Steareth-20 bad for acne-prone skin?
Because it barely registers on the comedogenic scale, Steareth-20 is generally a safe pick for breakout-prone skin and is often recommended as a gentler alternative to heavier ingredients.
Worth flagging: Steareth-20's rating is disputed. Credible sources land on different numbers, which is why we show a range rather than a single score — and why your own experience is the best tiebreaker.
Note for fungal-acne (malassezia) sufferers: Steareth-20 is commonly avoided in fungal-acne routines, since it falls into the fatty-acid or ester families the yeast can feed on. The evidence there is looser than for comedogenicity — see our fungal-acne checker for context.