Parent commenter here - I don't doubt that LSD has real effects. I think it's plausible that microdosing has real effects. But I also think that said effects are difficult to measure, because studies typically use subjective mood assessments, which are going to be pretty heavily impacted by the placebo effect.

But even if most of microdosing is just a placebo effect, I think that's still amazing in itself. Even if you're not "physically tripping", you've willed yourself into a "more open" mental state, creating your own positive side effects.