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Microdosing: what the placebo-controlled trials show

Does taking tiny doses of LSD or psilocybin improve mood or focus? What the placebo-controlled trials found, and why the evidence is still unsettled.

ReviewedLast updated September 25, 2026

The short answer

Microdosing means regularly taking a very small dose of a psychedelic, typically LSD or psilocybin, around a tenth of a full dose or less, every few days. It’s meant to be below the level that causes a full psychedelic experience. People report better mood, focus and creativity.

In placebo-controlled trials in healthy adults, microdoses often produce noticeable effects on the day they’re taken. But they haven’t produced lasting improvements in mood or thinking beyond what placebo produces.9 Whether microdosing helps people with depression or other conditions hasn’t yet been tested in a completed randomised trial.

Question Evidence
Improves mood or cognition in healthy adults, beyond placebo Moderate Mostly no lasting effect
Produces noticeable effects on dosing days Moderate Yes, often
Treats depression Very low One small open-label study

The key trials

The largest placebo-controlled study, 2021. In a “self-blinding” citizen-science study, 191 people who were already planning to microdose set up their own placebo capsules. After four weeks, the microdose group had improved on every psychological measure, but so had the placebo group, with no significant difference between them. The small differences that did appear could be explained by people guessing which capsules they had.1

LSD at home, 2023. In a trial of 80 healthy men, half took 10 µg of LSD and half a placebo every three days for six weeks, mostly at home. On dosing days, the LSD group reported more creativity, energy, happiness and connectedness. But at the end of six weeks there was no lasting change in mood or cognition. Four people in the LSD group withdrew because of anxiety.2

LSD in the lab, 2019–2022. In controlled lab studies, doses of about 10–26 µg produced noticeable, dose-related effects.45 One study found some acute improvements in mood and attention, alongside more anxiety and confusion.5 But in a study of four repeated doses over about two weeks, LSD “did not improve mood” or performance.3

Psilocybin mushrooms, 2022–2026. In a study of 34 people starting to microdose mushrooms, effects on experience were stronger than placebo only for people who correctly guessed they had the real dose. There was no improvement in creativity or cognition, and a few small changes toward impairment.6 Two further double-blind trials of psilocybin truffles found no significant effects on cognition or wellbeing compared with placebo.7

Is it all placebo?

Not necessarily. A 2024 review of 19 placebo-controlled studies argues it’s too early to call microdosing “just placebo”. The studies have been small, used few doses, and tested mostly healthy people rather than people with depression or ADHD, who might respond differently. The measured effect of expectation has also been small.8

Depression. In an open-label trial, 19 people with depression, most of whom were on antidepressants, took LSD microdoses twice a week for eight weeks. Depression scores fell by about 60%, and the improvement was sustained for up to six months. With no placebo group, this can’t separate the drug’s effect from expectation.10 A randomised, placebo-controlled follow-up trial (LSDDEP2) has been designed to test this properly.11

Safety

In reviews of controlled studies, side effects were usually mild, short-lived and dose-dependent. The most common were raised blood pressure, anxiety and some cognitive impairment.12 Anxiety was the main reason people dropped out of the home-dosing LSD trial.2 There’s a theoretical concern about heart-valve effects from long-term repeated dosing. The first trial to check for this with heart scans found no problems, but it was small and short.10

References

  1. Szigeti B, et al. Self-blinding citizen science to explore psychedelic microdosing. eLife. 2021;10:e62878. Source
  2. Murphy RJ, et al. Acute mood-elevating properties of microdosed lysergic acid diethylamide in healthy volunteers: a home-administered randomized controlled trial. Biological Psychiatry. 2023;94(6):511–521. Source
  3. de Wit H, et al. Repeated low doses of LSD in healthy adults: a placebo-controlled, dose-response study. Addiction Biology. 2022;27(2):e13143. Source
  4. Bershad AK, et al. Acute subjective and behavioral effects of microdoses of lysergic acid diethylamide in healthy human volunteers. Biological Psychiatry. 2019;86(10):792–800. Source
  5. Hutten NRPW, et al. Mood and cognition after administration of low LSD doses in healthy volunteers: a placebo controlled dose-effect finding study. European Neuropsychopharmacology. 2020;41:81–91. Source
  6. Cavanna F, et al. Microdosing with psilocybin mushrooms: a double-blind placebo-controlled study. Translational Psychiatry. 2022;12(1):307. Source
  7. Prochazkova L, et al. Cognitive and subjective effects of psilocybin microdosing: results from two double-blind placebo-controlled trials. Neuropharmacology. 2026;283:110722. Source
  8. Polito V, Liknaitzky P. Is microdosing a placebo? A rapid review of low-dose LSD and psilocybin research. Journal of Psychopharmacology. 2024;38(8):701–711. Source
  9. Meshkat S, et al. Efficacy and safety of psychedelic microdosing on psychological outcomes in healthy adults: a systematic review. CNS Drugs. 2026;40(10):1369–1393. Source
  10. Daldegan-Bueno D, et al. LSD microdosing in major depressive disorder: results from an open-label trial. Neuropharmacology. 2026;283:110762. Source
  11. Daldegan-Bueno D, et al. LSDDEP2: study protocol for a randomised, double-dummy, triple-blind, active placebo-controlled, parallel groups trial of LSD microdosing in patients with major depressive disorder. Trials. 2024;25(1):560. Source
  12. Modzelewski S, et al. Side effects of microdosing lysergic acid diethylamide and psilocybin: a systematic review of potential risks. Neuropharmacology. 2025;271:110402. Source