What is PEG-100 Stearate?
PEG-100 Stearate is an emulsifier that helps oil and water mix. A very common co-emulsifier (usually paired with glyceryl stearate) that is low-risk at 1/5, though a fatty-acid ester.
You may see it on labels as Peg-100 Stearate, Peg 100 Stearate, so it can hide under more than one name in an ingredient list.
Where PEG-100 Stearate shows up
You'll most often find PEG-100 Stearate 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 PEG-100 Stearate bad for acne-prone skin?
That low score makes PEG-100 Stearate a reasonable choice even for acne-prone skin. As always, individual reactions vary, but it is not a likely cause of clogged pores.
Note for fungal-acne (malassezia) sufferers: PEG-100 Stearate 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.