Less is more? A review of psilocybin microdosing

A semi-structured review of psilocybin microdosing—taking sub-hallucinogenic doses of the psychedelic compound found in magic mushrooms—identified major research gaps that prevent firm conclusions about its benefits. Most available evidence comes from observational studies, while clinical and non-clinical trials remain sparse and inconsistent. The review highlights the need for more randomized placebo-controlled trials, studies of dose-response relationships, psychological and personality testing, use of active placebos, diverse study populations, psilocybin-exclusive microdosing research, and refined animal models. Definitive conclusions about efficacy remain elusive.

Study at a glance

Abstract

Background: The applications of psilocybin, derived from ‘magic mushrooms,’ are vast, including a burgeoning practice known as microdosing, which refers to the administration of sub-hallucinogenic doses of psychedelic substances to obtain benefits without experiencing significant cognitive and perceptual distortion. However, current research is fairly new with several limitations and gaps that hinder adequate conclusions on its efficacy. Aims: This semi-structured review aimed to identify and highlight research gaps in the field of psilocybin microdosing for future research. Methods: A Preferred Reporting Items for Systematic Reviews and Meta-Analyses based strategy was employed, utilizing a chain of keywords and key phrases across multiple databases, augmented by a cross-sectional Google search for relevant grey literature in the form of the top 10 search results. A total of 40 studies and 8 unique websites were identified, summarized and tabulated into four distinct categories, namely non-clinical, clinical, observational and anecdotal evidence. Results: The majority of available evidence originates from observational studies, while non-clinical and clinical study findings remain comparatively sparse and inconsistent. Web-based findings were consistent with current research findings. Key research gaps were highlighted: the imperative for more randomized placebo-controlled trials, exploration of dose-response ranges, psychological and personality testing of participants, utilization of active placebos, greater diversity in study populations, an increase in psilocybin-exclusive microdosing studies and the refinement of animal models. Conclusion: Definitive conclusions regarding the efficacy of psilocybin microdosing remain elusive, emphasizing the need for further study. Numerous research gaps necessitate consideration for future investigations.