Tea tree oil
Melaleuca Alternifolia Leaf Oil
Evidence for mild-to-moderate acne at around 5%. Must be diluted; sensitising neat.
How solid is the pore-clogging number
Tea tree oil rates 1 of 5 — unlikely to clog pores for most people. The rating is graded established. Traceable to published comedogenicity testing and consistent across sources.
It describes the raw ingredient in isolation. In a finished product, how much is present and where it sits in the list matter just as much. Check a whole label to see it in context.