- The side effects of microdosing LSD and psilocybin are mostly mild, dose-dependent, and transient, including increased blood pressure, anxiety, and cognitive impairment.
- There’s a significant lack of standardized reporting on side effects across studies, which hampers the ability to draw clear conclusions about the safety of microdosing practices.
- Future research should prioritize systematic methodologies, longer study durations, and standardized assessments to accurately evaluate the risks and benefits of microdosing.
Background
Psychedelics have been the subject of research for many years, particularly concerning their therapeutic potential for mental health conditions like depression and anxiety. After facing political and regulatory challenges in the 1970s that curtailed research, interest in psychedelics has been revived in recent years. This resurgence has led to significant policy changes, including the decriminalization of substances like psilocybin in select jurisdictions and its medical approval for treating PTSD in Australia. One notable practice gaining popularity in this renewed interest is microdosing, which entails regularly consuming low doses of psychedelics such as LSD or psilocybin. Proponents assert that this practice can lead to enhanced mood and cognitive abilities while alleviating anxiety and depressive symptoms. However, data on its safety and potential side effects remain sparse, which this systematic review seeks to investigate.Definition of Microdosing
Microdosing is conventionally defined as taking about one-tenth to one-twentieth of a full psychedelic dose, intended to yield subtle psychological and emotional benefits without inducing notable perceptual effects such as hallucinations. The Fadiman method is a widely practiced regimen, involving dosing every third day, while other methods incorporate different schedules based on individual preferences. There is no universally agreed-upon dosage for microdosing. For LSD, doses generally range between 5 to 25 micrograms, and for psilocybin, doses fall within 0.1 to 0.5 grams of dried mushrooms, translating to approximately 1 to 5 milligrams of synthetic psilocybin. Individual sensitivities and varying potencies of these substances can produce different experiences for each user.Methods
The systematic review adhered to PRISMA guidelines, which provide a framework for conducting and reporting systematic reviews effectively. The researchers examined three major databases—PubMed, Web of Science, and Scopus—up until August 3, 2024, to find original studies detailing the side effects of microdosing LSD and psilocybin. The inclusion criteria focused on studies that specifically addressed microdosing, reported adverse effects in controlled settings, and were published in peer-reviewed journals in English. Excluded studies lacked details on side effects or did not discuss microdosing protocols. After thoroughly vetting 417 initial studies, 31 were deemed suitable for analysis, comprising 15 laboratory studies, 14 observational studies, and 2 clinical case reports.Results
General Characteristics of Side Effects
The review revealed that most reported side effects from microdosing were generally mild, temporary, and associated with the doses taken. Frequently documented effects included increased blood pressure, anxiety, cognitive impairments, gastrointestinal issues, headaches, and disturbances in sleep. These adverse effects were typically quick to arise post-consumption and resolved within a few hours. Higher-quality laboratory studies provided more structured assessments of side effects, but their short duration often limited the findings. Conversely, observational studies derived insights from personal reports but lacked the rigor of standardized assessment methods.Physiological Side Effects
Gastrointestinal issues, especially nausea and stomach discomfort, were prevalent in studies revolving around psilocybin microdosing. Some users reported mild digestive issues, which generally subsided quickly. In LSD studies, headaches surfaced frequently after the primary effects diminished, while psilocybin microdosing seemed to result in fewer instances of headaches. Notably, microdosing psychedelics was associated with slight, temporary spikes in blood pressure, particularly at higher doses, with values returning to normal within a few hours. These increases were more pronounced in individuals administering doses of 20 micrograms of LSD or higher. Fluctuations in body temperature were also mentioned, although lab studies did not identify significant physiological changes.Psychiatric and Cognitive Side Effects
Anxiety emerged as the most frequent psychological side effect, reported across nearly all studies. Some individuals manifested increased feelings of anxiety at higher doses or when predisposed to anxious tendencies. Only rare cases led to participants withdrawing due to discomfort. Cognitive issues, characterized by challenges in concentration, confusion, and slower response times, were sometimes noted, especially in studies examining LSD microdosing. However, consistency across findings was lacking, with some studies not indicating significant cognitive deficits. Mood swings were occasionally documented, with participants experiencing fleeting feelings of sadness or heightened emotional sensitivity. While hallucinations were absent, some minor perceptual changes, like enhanced light sensitivity, were reported in individuals consuming higher doses. Reports of sleep disturbances were frequent with LSD microdosing, with some individuals finding it hard to sleep, experiencing increased alertness, or having vivid dreams. Despite this, no physical addiction or dependence was observed.Discussion
The review indicates that microdosing psychedelics is generally well-received, as the side effects noted were typically mild and transient. However, instances of anxiety and cognitive issues were observed, suggesting that microdosing carries some risks. A major limitation of the examined research is the inconsistency in how side effects were reported and the brief nature of many studies. Most laboratory evaluations focused on single doses rather than extended microdosing across time, leaving questions regarding the cumulative effects of prolonged use. Moving forward, the authors recommend the establishment of more standardized research methodologies that incorporate longer evaluation periods and unified approaches to reporting side effects. Clinical trials are warranted to assess long-term microdosing in controlled settings, which could elucidate the risks and benefits more clearly.Conclusion
This systematic review underscores that while microdosing with LSD and psilocybin appears reasonably safe, mild side effects occur with notable frequency. Increased blood pressure, anxiety, and cognitive disturbances represent the most commonly reported adverse effects. The variation in methodologies across studies highlights an urgent need for more rigorous research to solidify the long-term safety profile of microdosing, focusing on standardized dosing regimens and improved data-collection practices.See also our coverage of Assessing the Potential Cardiovascular Risk of Microdosing. Read the full paper summary on Blossom.
