Microdosing: A Systematic Review of Current Evidence
The evidence for microdosing is thinner than the enthusiasm — but not empty.
This systematic review covers 23 peer-reviewed studies on sub-perceptual psychedelic dosing (psilocybin 0.1–0.3g, LSD 5–20μg) published between 2018 and 2024. The evidence base is limited by small sample sizes, high attrition, and the predominance of self-report measures. No study to date has met the threshold for a confirmatory Phase III trial.
Findings are mixed. Self-report studies consistently show improvements in mood, focus, and creativity. Placebo-controlled studies show smaller effects, with several finding no significant difference between microdose and placebo on primary outcomes. The 'expectancy effect' — improvement driven by the belief that one is receiving an active substance — accounts for a substantial portion of the observed benefit.
This does not mean microdosing is ineffective. It means the evidence is insufficient to distinguish a pharmacological effect from an expectancy effect, and both may be real. The review recommends that future studies employ active placebos (compounds that produce mild somatic effects) to control for expectancy, and that researchers take seriously the possibility that the ritual of dosing — the daily act of intentional self-care — may be the primary active ingredient, regardless of what is in the capsule.
