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10 Million Americans Microdosed Last Year. The Neuroscience Is Just Catching Up.

The RAND Corporation confirmed what was once an underground whisper — 10 million US adults microdosed psychedelics in 2025. The public's belief has sprinted ahead of the science. Here's what we actually know, what we don't, and why the gap matters.

By The Microdose Movement ·

10 Million Americans Microdosed Last Year. The Neuroscience Is Just Catching Up.

Ten million people.

That is not a subculture. That is more people than live in the entire state of Michigan. It is more than the population of 41 US states. And according to the RAND Corporation’s first-ever nationally representative survey of psychedelic use — published in January 2026 — it is the number of American adults who microdosed psilocybin, LSD, or MDMA in 2025.

Let that land for a second. A practice that, fifteen years ago, was mostly whispered about on niche forums and discussed in hushed tones at Burning Man is now engaging roughly 3.7% of the US adult population. The underground went mainstream while nobody was looking.

But here is the part that does not get said enough: the public’s belief in what microdosing does has sprinted far ahead of what the science has actually demonstrated. We are living through a strange moment where millions of people are running a distributed, uncontrolled experiment on their own nervous systems — and the people in lab coats are still figuring out what, exactly, is happening at the synapse.

This is not an argument against microdosing. It is an argument for being honest about what we know, what we are guessing at, and why that distinction matters — especially when 10 million people are involved.

What the RAND study actually found

The 2025 RAND Psychedelics Survey, led by researcher Michelle Priest and co-directed by Beau Kilmer at the RAND Drug Policy Research Center, surveyed a probability-based, nationally representative sample of 10,122 US adults through the AmeriSpeak panel at NORC, University of Chicago. This was not an opt-in internet poll. It was the real thing — weighted, demographically calibrated, and designed to produce numbers you can actually stand behind.

The headline findings:

To put that last number in perspective: Americans spent roughly 100 million collective days last year taking sub-perceptual doses of a compound that, until recently, was Schedule I and officially classified as having “no currently accepted medical use.”

The survey defined microdosing for respondents as “taking a small fraction of a regular dose (a subperceptual dose) that is much lower than you would take to ‘trip’ or hallucinate.” The definition is worth noting because one of the persistent problems in microdosing research is that “microdose” means different things to different people. RAND standardized the definition for their respondents, which makes their numbers more interpretable than most.

Another number worth sitting with: of the total psilocybin consumed by weight in 2025, only about 8.2% came from microdosing. The remaining 91.8% was full-dose use. Microdosing dominates the days of use, but full-dose dominates the volume. The practice is widespread in time but modest in total consumption. (RAND, Priest et al., 2026)

What the neuroscience says — and the category error we keep making

If you have followed the psychedelic renaissance at all, you have probably heard some version of this: “Psilocybin grows new brain cells.” “Psilocybin rewires the brain.” “Psilocybin increases neuroplasticity.”

These statements are directionally true. But they come almost entirely from high-dose research, and the leap from “25 milligrams of pharmaceutical-grade psilocybin in a controlled clinical setting” to “0.1 grams of dried mushroom on a Tuesday morning” is not a small one. Let’s look at what the research actually shows.

The high-dose evidence (which is solid)

In 2021, a team at Yale led by Ling-Xiao Shao published a paper in Neuron that became one of the most-cited studies in the field. They gave mice a single dose of psilocybin and watched what happened to the neurons in the medial frontal cortex. The result: a ~10% increase in dendritic spine density and size within 24 hours, and the changes were still present a month later (Shao et al., Neuron, 2021). Dendritic spines are the tiny protrusions on neurons where synapses form. More spines, roughly speaking, means more potential connection points. More connection points means more capacity for learning, adaptation, and change.

A 2026 study in Nature Communications by Taylor Lyons and colleagues took this into humans — specifically, 28 healthy adults who had never taken a psychedelic before. Each participant received 1 mg of psilocybin as a control (sub-perceptual, essentially a placebo) and then, one month later, a full 25 mg dose. The researchers ran EEG and multiple forms of MRI at multiple time points.

The findings: after the 25 mg dose, brain entropy (Lempel-Ziv complexity) spiked significantly during the acute experience. One month later, structural changes were still detectable — specifically, decreased axial diffusivity in the prefrontal cortex-striatum and prefrontal cortex-thalamus tracts, which the authors cautiously interpret as possible evidence of neural remodeling. Decreased network modularity (a measure of how segregated different brain networks are) correlated significantly with improvements in psychological well-being (Lyons et al., Nature Communications, 2026).

These are real findings from real labs. They are exciting. They are also, crucially, about full-dose psilocybin in controlled settings with preparation, supervision, and integration support. None of them looked at microdosing.

The microdosing evidence (which is thin)

The controlled evidence on microdosing specifically paints a much murkier picture. A 2026 review from the clinical research sector summarized the state of the field bluntly: the evidence across controlled microdosing studies is “mixed and inconclusive” (CCRPS, 2026).

The core problem is not that microdosing has been disproven. It is that the studies that exist are plagued by a methodological headache: expectancy. People who sign up for microdosing studies generally believe microdosing works. When they get a placebo, many of them still report improvements. When they get the real thing, the improvements are often not statistically distinguishable from the placebo group — not because there is no effect, necessarily, but because the expectancy effect is so strong it swamps the signal.

The high-dose research gets around this partly because a 25 mg dose announces itself unmistakably. Nobody on 25 mg wonders if they got the placebo. But microdosing, by design, is sub-perceptual. The whole point is that you do not feel it acutely. Which means the line between “the molecule is doing something” and “I believe the molecule is doing something” is extraordinarily hard to draw.

This does not make microdosing fake. It makes it scientifically slippery. And that slipperiness is exactly why some of the loudest claims in the space deserve more skepticism than they usually get.

Why 10 million people are doing it anyway

If the evidence is mixed, why are so many people microdosing?

The short answer is that people do not wait for peer review before trying things that might help them feel more alive. And the cultural conditions that make microdosing appealing are not subtle.

The mental health default settings are failing. Not for everyone, but for enough people that the alternatives start looking rational. SSRIs help millions of people — and for millions of others, the experience can include emotional flattening, sexual side effects, and a persistent sense of being stuck. Talk therapy is expensive, hard to access, and often slow. Founder burnout has become its own genre of business literature at this point, and “nervous system regulation” has gone from niche biohacker language to something you hear on mainstream podcasts. A lot of people are running on fumes and looking for something that actually moves the needle.

The attention economy is shredding focus. If your attention is being auctioned off to the highest bidder every time you open your phone, the search for a compound that might help you reclaim it starts making a certain kind of sense. Whether or not microdosing reliably improves focus in controlled trials, the felt need for better focus is real and growing.

The psychedelic renaissance has credibility. When Johns Hopkins, Imperial College London, Yale, and Nature are all publishing psychedelic research, the practice loses its countercultural stigma and gains a gloss of scientific legitimacy. The problem is that this legitimacy attaches to the category of psychedelics, not necessarily to the specific practice of microdosing. The high-dose research rubs off on the microdosing conversation in ways that are not always warranted.

None of this makes microdosers irrational. It makes them human — responding to real problems with the tools available to them, in the absence of clear institutional guidance. The RAND finding that 69% of psilocybin users microdose suggests that, for most people, the value proposition is not the journey. It is the Tuesday.

What honest conversation looks like

So where does this leave us?

If you are microdosing — or considering it — the honest posture is something like this: you are participating in a practice that millions of people find valuable, that has plausible mechanistic support from adjacent high-dose research, and that has not yet been demonstrated to produce reliable, expectancy-surpassing effects in controlled trials. All three of those things can be true at once.

The responsible way to hold this is:

Stay curious about what you are actually experiencing. Track it. Keep a log. Notice when you are feeling better and when you are not. The best data you have is your own, but only if you actually pay attention to it.

Do not import high-dose claims into a microdosing context. When someone says “psilocybin has been shown to increase neuroplasticity,” the honest follow-up is: “At what dose, in what setting, and in what population?” The Shao study was mice. The Lyons study was 25 mg in psychedelic-naïve humans. Neither of those is your Tuesday morning protocol.

Admit what you do not know. The research is genuinely incomplete. That is not a failure of the research community — it is a reflection of how recently this became a serious scientific question. Admitting uncertainty is not weakness. It is the foundation that better understanding gets built on.

The mushroom is the door. But walking through it with your eyes open — that is on you.

FAQ

Is microdosing the same thing as the clinical psilocybin research I keep reading about?

No. Most of the high-profile psilocybin research — at Johns Hopkins, Imperial College London, and elsewhere — involves full doses (typically 20-25 mg of synthesized psilocybin) administered in controlled therapeutic settings with preparation and integration sessions. Microdosing involves sub-perceptual doses (roughly 1/10th to 1/20th of a full dose) taken on a regular schedule, typically without therapeutic supervision. The evidence base for full-dose therapy is substantially stronger than the evidence base for microdosing.

How many people are actually microdosing?

According to the RAND Corporation’s 2025 nationally representative survey, approximately 10 million US adults microdosed psilocybin, LSD, or MDMA at least once in 2025. Among past-year psilocybin users specifically, 69% reported microdosing. The number may be higher since the survey did not include microdosing of ketamine, Amanita muscaria, or other substances.

Does psilocybin actually increase neuroplasticity?

Research suggests that a single full dose of psilocybin can produce measurable changes in dendritic spine density and brain network connectivity. The foundational study (Shao et al., Neuron, 2021) found ~10% increases in dendritic spine density in mice. The 2026 Lyons et al. study in Nature Communications found structural brain changes persisting one month after a single 25 mg dose in humans. However, these findings are from full-dose studies — they do not directly translate to microdosing, and the neuroplastic effects of sub-perceptual doses have not been established in controlled research.

Is microdosing safe?

The existing evidence suggests that microdosing psilocybin at typical doses has a relatively low acute risk profile for most healthy adults. However, long-term safety data is essentially nonexistent. People with personal or family histories of psychosis, bipolar disorder, or certain cardiovascular conditions should exercise particular caution. As with any practice that involves a psychoactive compound, doing your own research, consulting qualified professionals, and starting very low and slow is the prudent approach.

Sources

Medical Disclaimer: This article is for educational and informational purposes only. It does not constitute medical advice, diagnosis, or treatment. Psilocybin remains a Schedule I controlled substance under US federal law. The Microdose Movement does not encourage, condone, or facilitate any illegal activity. Always consult a qualified healthcare professional before making any changes to your health regimen, especially regarding psychoactive substances.