Single low doses of LSD produced selective, beneficial effects on mood and thinking in healthy volunteers, with 5 micrograms the smallest noticeable dose
A 2020 controlled study gave healthy volunteers single low doses of LSD — the microgram-level amounts people take when 'microdosing' — to find the smallest dose that noticeably affects mood and thinking.
Microdosing means taking a tiny fraction of a full psychedelic dose, and people who do it say it lifts their mood and sharpens their focus — but controlled research is scarce. This study set out to find the smallest dose of LSD that actually registers. Twenty-four healthy volunteers each received a placebo (a dummy dose) and three low doses of LSD — 5, 10, and 20 micrograms — in separate sessions, and researchers tracked their mood and mental performance for about six hours after each dose. The low doses mostly had positive effects, such as better mood, more friendliness, more alertness, and fewer lapses in attention, alongside some negative ones like more confusion and anxiety. The smallest dose people noticeably felt was 5 micrograms, and the clearest effects appeared at 20 micrograms. This was a small study in healthy people testing single doses, not the repeated schedule microdosers use.
In this placebo-controlled, within-subject dose-finding study, 24 healthy volunteers each received placebo and three low doses of LSD (5, 10, and 20 mcg) across separate sessions, with acute effects on cognition, mood, and subjective experience assessed up to 6 hours after administration using the Psychomotor Vigilance Task, Digit Symbol Substitution Test, Cognitive Control Task, Profile of Mood States, and 5-Dimensional Altered States of Consciousness rating scale. LSD produced positive effects in the majority of observations — increased positive mood (20 mcg), friendliness (5 and 20 mcg), arousal (5 mcg), and decreased attentional lapses (5 and 20 mcg) — alongside negative effects, namely increased confusion (20 mcg) and anxiety (5 and 20 mcg), and psychedelic-induced changes in waking consciousness (10 and 20 mcg). The authors concluded that low doses of LSD produced selective, beneficial effects on mood and cognition in the majority of observations; the minimal dose at which subjective and performance effects were notable was 5 mcg, and the most apparent effects appeared after 20 mcg.
The authors' Discussion (behind a paywall) was not accessible, so the caveats below are design-inherent rather than the authors' own stated limitations. This was a small study (24 healthy volunteers) in a general-population, non-clinical, non-veteran sample, so it does not establish that low-dose LSD relieves symptoms in people seeking help for a diagnosed condition — the study's stated aim was dose-finding (identifying the minimal acutely active dose), not treatment efficacy. It measured the acute effects of single doses over roughly one day, not the repeated dosing schedule that defines microdosing over weeks, so it cannot speak to cumulative or longer-term effects. Because low doses of LSD can produce noticeable subjective effects, participants may have been able to sense when they received the active drug rather than placebo, which can shape expectancy. The abstract describes the design as placebo-controlled and within-subject; the accessible source does not state the specific blinding procedure, so this entry does not characterize it. Authors declared no conflict of interest.
In this placebo-controlled within-subject dose-finding study, 24 healthy participants received acute low doses of LSD (5, 10, and 20 mcg), and the authors reported that the minimal dose at which subjective and performance effects are notable is 5 mcg and the most apparent effects were visible after 20 mcg (Hutten et al., 2020, European Neuropsychopharmacology).
Read the full paper →