What is Isopropyl Isostearate?
Isopropyl Isostearate is a synthetic emollient ester. A branched isostearic ester in the same family as isopropyl myristate. Non-irritating but rated the maximum 5 for pore-clogging potential.
Where Isopropyl Isostearate shows up
You'll most often find Isopropyl Isostearate in lotions, sunscreens, primers, and colour cosmetics, where it adds a smooth, non-greasy slip. Separately from clogging, its irritancy is rated 0/5 — low, so it's unlikely to sting or sensitise on its own.
Is Isopropyl Isostearate bad for acne-prone skin?
On acne-prone skin, Isopropyl Isostearate has a real chance of contributing to congestion. Check its position on the ingredient list before you worry — concentration changes everything.
Note for fungal-acne (malassezia) sufferers: Isopropyl Isostearate 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.
Non-comedogenic alternatives
If you're avoiding Isopropyl Isostearate, these lower-risk ingredients serve a similar role and are gentler on pore-prone skin:
- Caprylic/Capric Triglyceride — rated 1/5 (Low risk).
- Squalane — rated 1/5 (Low risk).