Research Watch
Microdosing: the evidence, minus the hype
The best-controlled studies keep finding the same thing, and it isn't what the internet says. Placebo is doing more work here than most people want to hear.
Microdosing has the best story in the field: no lost day, no visions, just a slightly better version of you. It also has the weakest evidence in the field, and the gap between those two facts is where a lot of money currently sits.
The study that ought to have settled it
In 2021, Balázs Szigeti and colleagues published a clever piece of work in eLife. Rather than bring people into a lab, they let existing microdosers blind themselves. Participants filled their own opaque capsules, some with their microdose and some with nothing, sealed them into QR-coded envelopes and self-allocated across four weeks while the researchers held the key. Substances were mostly LSD around 13 micrograms or roughly 0.2g of dried mushrooms. Of 1,630 sign-ups, 240 started and 191 completed, and 191 is the number the analysis rests on.
The result, in the authors' words: all psychological outcomes improved significantly from baseline in the microdose group, but the placebo group also improved, and there were no significant differences between them. Where small microdose-versus-placebo differences did appear, the authors concluded these "can be explained by participants breaking blind", and that "anecdotal benefits of microdosing can be explained by the placebo effect."
One detail deserves its own paragraph. Participants correctly identified what they had taken about 72% of the time, with a detection threshold estimated around 12 micrograms of LSD, which sits squarely inside the normal microdose range. So microdoses are not reliably sub-perceptual. People can often tell, which is exactly the mechanism by which expectation gets to work.
The laboratory picture agrees
Harriet de Wit's lab at Chicago has run the most careful controlled work on low-dose LSD, and the pattern is consistent across studies. Anya Bershad and colleagues (2019, Biological Psychiatry, 20 participants, doses of 0, 6.5, 13 and 26 micrograms) found only the highest dose raised subjective vigour, with no significant effects on depression, working memory, processing speed or creativity. A repeated-dose study in 2022 with 56 participants over four doses concluded that low doses were safe but produced "negligible changes in mood or cognition."
What that lab does find, repeatedly, is measurable neurophysiology: changes in EEG power, in reward-related brain responses, in neural complexity. So something is happening. It is just not showing up as people performing better or feeling better on the measures that matter.
A 2022 double-blind study by Cavanna and colleagues in Translational Psychiatry tested 0.5g of dried mushrooms in 34 people already about to start microdosing, and reached a similar place: acute effects were felt more strongly on active doses, without the durable benefits the practice is sold on.
The most suggestive positive signal is a 2024 crossover study from de Wit's lab in which participants with higher baseline depression scores reported greater drug effects and larger mood improvement at 48 hours. That is 39 people in a single study, and it points at a real question worth pursuing rather than an answer.
Why the anecdotes are not lying
This is the part usually handled badly by both sides. If thousands of people report that microdosing helped them, they are almost certainly reporting something true about their experience. The question is what caused it.
A placebo effect is not nothing happening. It is a real change produced by expectation, ritual and attention, and it can be substantial. Someone who buys a scale, weighs a dose, takes it on a schedule and pays close attention to their mood has introduced a great deal of structure and self-observation into their week. The self-blinding study is essentially the finding that when you remove the knowing, most of the benefit goes with it.
And a risk nobody advertises
Chronic activation of the 5-HT2B receptor is associated with heart valve disease, which is why certain older drugs were withdrawn. Whether repeated microdosing over years carries meaningful cardiac risk is not established, but it is taken seriously enough that some trial protocols now require echocardiograms at baseline and follow-up, and exclude people with existing valve disease. "Small dose, small risk" is an assumption, not a finding.
The honest summary
Full-dose psilocybin therapy has phase 3 data behind it. Microdosing has an enthusiastic community, a plausible hypothesis and, so far, no controlled evidence that it beats an identical-looking capsule of nothing. Those two things get talked about as if they were the same field. They are not, and conflating them makes the stronger evidence easier to dismiss.
