A newly published study in Nature Partner Journals’ Aging demonstrates that psilocin, a byproduct of consuming psilocybin, the active ingredient in psychedelic mushrooms,

Maybe my memory is wrong, but I had it the other way around: Psilocin is the active substance, but its not very stable. Psilocybin gets metabolized to Psilocin. Calling it a "byproduct" is kind of underselling it. Psilocybin itself isn't active by itself.

Quick wiki check confirms this. I always have troubles with articles opening with. I can't even read that as unfortunate wording.