Butterbur
How solid is the pore-clogging number
Butterbur rates 0 of 5 — no observed follicular occlusion in testing. The rating is graded disputed. Sources disagree. This figure circulates on clinic lists without a clear original citation, so treat it as a reason to patch test rather than a settled number.
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.