What a 2/5 rating means
On the comedogenic scale, a 2 is still within the non-comedogenic range that dermatologists generally consider low-risk. That places Steareth-20 in the range most people, including many with acne-prone skin, tolerate well.
This rating is disputed. Credible sources land on different numbers for Steareth-20, so we publish the range (2) rather than a false single figure. When sources disagree this openly, your own experience carries real weight.
One thing the number cannot tell you is concentration. Ingredients are listed in descending order, so Steareth-20 near the end of a label is present in tiny amounts and matters far less than the same ingredient near the top.
About Steareth-20
It is an emulsifier, the ingredient that keeps a product's oil and water phases from separating. A common ethoxylated stearyl emulsifier listed in the low-moderate range.
On a label it can read as Steareth-20, Steareth 20 — worth knowing when you scan an ingredient deck.
Steareth-20 in makeup and skincare
It quietly stabilises most cream foundations, lotions, and moisturisers. Its irritancy is rated separately at 0/5, which is low.
If you deal with fungal acne (malassezia folliculitis) rather than ordinary clogged pores, note that Steareth-20 is among the fatty-acid or ester-type ingredients that community sources commonly avoid — a separate concern from its comedogenic score, and one with weaker evidence behind it.