In brief
- The largest placebo-controlled study on microdosing (191 participants) found no significant differences between microdoses and placebos regarding well-being, life satisfaction, or mindfulness.
- Both groups improved; much of the perceived benefit appeared to depend on what the person believed they had taken, rather than the substance itself.
- This is not proof that microdosing “does nothing”: evidence remains early-stage, and other studies have detected pharmacological signals. It is neither a miracle nor a hoax.
Microdosing—the regular consumption of very small doses of LSD or psilocybin, well below the threshold that produces perceptual effects—has become popular with promises of increased creativity, focus, and well-being. When science has put it to the test with a control group taking a placebo, the results have been more sobering: people who microdose do improve, yes, but those taking inert pills improve as well, and the differences between the two groups tend to vanish.
The study
The most representative work was published in the open-access journal eLife in 2021, led by Balázs Szigeti and his team at Imperial College London. Their design was ingenious: instead of bringing people into a laboratory, they proposed a “self-blinding” method. 191 people who were already microdosing on their own participated; following online instructions, they prepared their own capsules—some with their substance, others with a placebo—identified by QR codes, so that neither they nor the researchers knew what each dose contained until the end. The follow-up lasted four weeks. It is the largest placebo-controlled study on psychedelics conducted to date, although it should be noted that it is not a standard clinical trial: the sample was self-selected, the substances were the participants’ own, and the doses were not standardized or verified in a laboratory.
What was found
Over the four weeks, both groups improved on several psychological measures: well-being, life satisfaction, and mindfulness, among others. The problem for the microdosing hypothesis is that there were no statistically significant differences between those who took microdoses and those who took a placebo. When examining acute effects—those on the day of ingestion—and taking into account what each person guessed about the content of their capsule, the differences, already small, disappeared on almost all scales, except for the subjective intensity of the experience. In other words: scores were better when the participant believed they had taken a microdose, regardless of what they had actually ingested. The authors concluded that a large part of the observed benefits can be explained by the placebo effect, that is, by expectation.
What it means (and what it doesn’t)
The finding is important, yet it should be read carefully in both directions. It means that expectation—the ritual of taking something in the hope of feeling better—has a real weight, and that many of the enthusiastic testimonials in circulation may reflect that mechanism rather than a clear pharmacological action. But it does not prove that microdoses lack effect: the study used self-administered and unverified doses, measured mostly subjective changes, and recruited people already convinced of the method, all of which limit the conclusions.
In fact, the literature is not unanimous. A 2024 review by Vince Polito and Paul Liknaitzky in the Journal of Psychopharmacology compiled 19 controlled studies and warned that there is also no solid evidence to reduce everything to a placebo: some studies describe effects that depend on the dose and neurobiological signals that a pure placebo would not explain. The field is, in reality, in an early phase: few laboratories, small samples (an average of about 31 people), almost always healthy volunteers, and short follow-ups. The honest conclusion is that research is promising but preliminary, and the most rigorous trials have not yet shown a robust and reproducible benefit compared to a placebo.
As an objective fact, in Spain, both LSD and psilocybin are listed as controlled substances, regardless of what science eventually concludes about their utility. Anyone considering these practices deserves truthful, non-exaggerated information: neither the promise of a cure nor moral condemnation helps one decide with autonomy. What we know today invites caution and, above all, following the well-designed trials currently underway closely.
Source
- Szigeti B, Kartner L, Blemings A, Rosas F, Feilding A, Nutt DJ, Carhart-Harris RL, Erritzoe D. Self-blinding citizen science to explore psychedelic microdosing. eLife, 2021;10:e62878. DOI: 10.7554/eLife.62878
Educational content written from a harm reduction perspective and with respect for individual freedom. It is not a substitute for advice from a healthcare professional and is not intended to encourage or condemn any drug use.
