I was surprised recently to see an ad for microdosing psilocybin (it's legal here). They don't even make an extract, just grind it up and put it in capsules so it comes with a disclaimer that the dosages are unpredictable.
Hm, my understanding is that powdering it tends to homogenize the stuff enough to mitigate most of those risks, assuming you do it in large enough batches.
Personally I prefer a lesser processed product than something extracted using solvents and who knows what other industrial processes/opportunity for toxic errors...
Psilocin/Psilocybin content can vary radically between mushrooms of the same species or even the same harvest. Microdosing lsd or mushrooms also runs into potential cardiovascular problems (from the same mechanism of action that made fenfluramine dangerous,) and recent studies cast doubt on whether there's any benefit.
Infrequent, responsible tripping is definitely more beneficial than microdosing, and medical science is finally being allowed to study psychedelics, so not microdosing until the heart health questions are answered seems a smart course of action.
That's implied with the "responsible" framing. Part of that means knowing your mental health situation, if you have family history of schizophrenia or other risk factors, or if your doctor recommends against it.
Another part is self-education. Have conversations, explore the intellectuals and history and science of the subject, and learn your mental health situation. If psychedelics are inappropriate, or if you're uncertain, then the responsible thing to do is to simply avoid them.
At any rate, it looks like microdosing, to our best understanding, lacks evidence of benefit when considered against the possibility of placebo. We also know that the potential for heart damage from microdosing recommends against it. Lastly, we know for a fact that responsible full dose trips are among the most positive and powerful experiences available for people. I'd call that "definite," within the constraints of responsible use.