What is Allantoin?
Allantoin is an active ingredient. A soothing, skin-conditioning active rated 0/5.
Where Allantoin shows up
You'll most often find Allantoin in targeted treatment products. Separately from clogging, its irritancy is rated 0/5 — low, so it's unlikely to sting or sensitise on its own.
Is Allantoin bad for acne-prone skin?
That low score makes Allantoin a reasonable choice even for acne-prone skin. As always, individual reactions vary, but it is not a likely cause of clogged pores.