What a 5/5 rating means
On the comedogenic scale, a 5 is the top of the scale — highly likely to clog pores when used at meaningful concentration. That means Isopropyl Isostearate deserves attention if you break out easily, especially when it appears high on an ingredient list.
One thing the number cannot tell you is concentration. Ingredients are listed in descending order, so Isopropyl Isostearate near the end of a label is present in tiny amounts and matters far less than the same ingredient near the top.
About Isopropyl Isostearate
It is a synthetic ester — an oil-and-alcohol reaction product engineered for a smooth, quick-absorbing slip. A branched isostearic ester in the same family as isopropyl myristate. Non-irritating but rated the maximum 5 for pore-clogging potential.
Isopropyl Isostearate in makeup and skincare
It is a workhorse of foundations, primers, sunscreens, and mascara, where a fast, silky slip sells the texture. 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 Isopropyl Isostearate 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.
Lower-rated alternatives to Isopropyl Isostearate
If you want a similar role with a friendlier comedogenic score, consider:
- Caprylic/Capric Triglyceride — comedogenic rating 1/5 (Low risk).
- Squalane — comedogenic rating 1/5 (Low risk).