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 Oleth-10 in the range most people, including many with acne-prone skin, tolerate well.
One thing the number cannot tell you is concentration. Ingredients are listed in descending order, so Oleth-10 near the end of a label is present in tiny amounts and matters far less than the same ingredient near the top.
About Oleth-10
It is an emulsifier, the ingredient that keeps a product's oil and water phases from separating. A higher-ethoxylate oleth that is milder than oleth-3, rated 2/5.
On a label it can read as Oleth-10, Oleth 10 — worth knowing when you scan an ingredient deck.
Oleth-10 in makeup and skincare
It quietly stabilises most cream foundations, lotions, and moisturisers. Its irritancy is rated separately at 1/5, which is low.
If you deal with fungal acne (malassezia folliculitis) rather than ordinary clogged pores, note that Oleth-10 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.