A systematic study of microdosing psychedelics

Microdosing had much smaller and different effects than participants in this two-part survey study (n=361) expected beforehand but were generally positive.


The phenomenon of ‘microdosing’, that is, regular ingestion of very small quantities of psychedelic substances, has seen a rapid explosion of popularity in recent years. Individuals who microdose report minimal acute effects from these substances yet claim a range of long-term general health and wellbeing benefits. There have been no published empirical studies of microdosing and the current legal and bureaucratic climate makes direct empirical investigation of the effects of psychedelics difficult. In Study One we conducted a systematic, observational investigation of individuals who microdose. We tracked the experiences of 98 microdosing participants, who provided daily ratings of psychological functioning over a six week period. 63 of these additionally completed a battery of psychometric measures tapping mood, attention, wellbeing, mystical experiences, personality, creativity, and sense of agency, at baseline and at completion of the study. Analyses of daily ratings revealed a general increase in reported psychological functioning across all measures on dosing days but limited evidence of residual effects on following days. Analyses of pre and post study measures revealed reductions in reported levels of depression and stress; lower levels of distractibility; increased absorption; and increased neuroticism. To better understand these findings, in Study Two we investigated pre-existing beliefs and expectations about the effects of microdosing in a sample of 263 naïve and experienced microdosers, so as to gauge expectancy bias. All participants believed that microdosing would have large and wide-ranging benefits in contrast to the limited outcomes reported by actual microdosers. Notably, the effects believed most likely to change were unrelated to the observed pattern of reported outcomes. The current results suggest that dose controlled empirical research on the impacts of microdosing on mental health and attentional capabilities are needed.

Authors: Vince Polito & Richard J. Stevenson


This paper is included in our ‘Top 10 Articles for Psychedelic Novices



Microdosing, a phenomenon that has seen a rapid explosion in popularity in recent years, has been observed to have minimal acute effects yet claims a range of long-term general health and wellbeing benefits. The current research suggests that dose controlled empirical research on the impacts of microdosing are needed.


Microdoses can be as small as one twentieth of a typical recreational dose, sometimes even less. People microdose using a wide range of different substances.

Psychedelics have been associated with marked alterations in cognition, affect, perception, and neurophysiology. Microdosing involves a ‘sub-threshold’ dose, where there are only minimal identifiable acute drug effects.

People follow a variety of different schedules when microdosing, but the most popular is to microdose every three days.

Despite the reported lack of acute effects of microdosing, proponents claim a wide variety of psychological and social benefits from regular use.

The earliest occurrence of microdosing is unknown, but traditional cultures used psychedelic plants for aphrodisiacs, to reduce hunger, inspire courage, nullify pain, and to treat ailments such as gout and syphilis.

Albert Hofman mentioned the use of very low doses of LSD in passing, but there is no formal research on microdosing prior to the prohibition of psychedelic research in 1966.

The current popularity of microdosing can be traced back to a book by James Fadiman, which described the practice in detail. This book triggered considerable popular media interest in microdosing, which has led to the emergence of multiple communities of microdosers on social media.

Four scientific articles on microdosing have been published. Three of these indicate potential benefits from microdosing, including improved mood, energy levels and cognition, as well as increased wisdom, open-mindedness and creativity.

Microdosers’ expectations are likely based on informal case reports, anecdotes, unpublished studies, and online publications, but scientific research suggests that psychedelics taken at higher doses may have therapeutic benefits.

Psilocybin and LSD have been shown to elicit mystical-type experiences that are characterised as highly meaningful and transformative by participants. Psilocybin has also been shown to increase emotional empathy, increase feelings of well-being, closeness to others and trust, and increase suggestibility.

In clinical trials, psilocybin and LSD have shown promise as treatments for end of life anxiety. Psilocybin has also been shown to reduce consumption levels when trialled as a treatment for tobacco addition and alcohol dependence.

As a result of increased research activity, researchers are developing a clearer picture of the psychopharmacological mechanisms that underlie psychedelic substances. These mechanisms include an agonistic effect on 5-HT2A receptors throughout the brain and structural changes in the posterior and anterior cingulate cortices.

Higher dose psychedelics appear to have beneficial effects across a range of psychological, cognitive, affective, and psychosocial domains, consistent with the diverse range of effects described by proponents of microdosing.

There has been no specific research into the safety of microdosing psychedelics, however research with higher doses of psychedelics suggests that these substances are relatively safe. Individuals do sometimes have disturbing experiences on psychedelics, but in general psychedelics are not addictive.

The motivation for the current study was to attempt to resolve some of the unknown questions around microdosing. Expectancy effects may be amplified by two factors: the effort required to source and prepare psychedelic substances, and the ambiguous immediate effect of each microdose.

We designed a study to examine the effects of microdosing on healthy individuals using well validated psychometric assessments. We restricted our analysis to serotonergic psychedelics, which act upon 5-HT receptor sites.

We identified nine domains for investigation in the effect of microdosing psychedelics: mood, attention, wellbeing, mindfulness, mystical experiences, personality, absorption, creativity, and sense of agency.

Study One

In Study One, microdosers were tracked daily for six weeks and completed comprehensive questionnaire batteries at baseline and at completion of the study.


1181 participants clicked through to the study webpage, 251 completed the baseline questionnaire, 98 reported microdosing with a serotonergic psychedelic, 63 completed the poststudy questionnaire, and 14 were female, 49 were male. The sample was highly educated, with 71.4% having completed postgraduate education.

Based on responses taken at baseline, this sample was experienced with psychedelics but reported relatively moderate experience with other drugs. Specifically, 9 out of 10 participants used psychedelics more than once a week.


Participants were informed that they had to be aware of microdosing and that they could not take part if they had any history of psychotic disorders. All interactions with participants were conducted through automated emails and online Qualtrics surveys. Participants completed a battery of measures investigating mood, attention, wellbeing, mindfulness, mystical experiences, personality, absorption, creativity, and sense of agency, and were also provided with instructions on how to create an anonymous email account.


Participants completed a brief rating scale each day during the study, adapted from Fadiman’s protocol. The scale was designed for brevity and took less than two minutes to complete.

We used the 21-item version of the DASS questionnaire to measure the severity of depression, anxiety and stress symptoms.

We used the Mind Wandering Questionnaire (MWQ) to measure deviations in attention away from the task at hand.

The QOLI is a 32 item scale that measures life satisfaction across 16 dimensions. It was used to measure health, self-esteem, goals and values, money, work, play, learning, helping, love and friends.

We used the Mindful Attention Awareness Scale (MAAS) to measure the frequency of mindful, receptive awareness of the present moment.

We used the Hood Mysticism Scale to measure the degree to which participants had mystical experiences during their lifetime.

We used the 50 item M5P Personality Questionnaire to measure five personality domains: Extraversion, Agreeableness, Conscientiousness, Neuroticism, and Openness.

We used the Tellegen Absorption Scale (TAS) to measure disposition toward intense imaginative experiences and a capacity to experience peaklike altered states of consciousness.

The Creative Personality Scale (CPS) is comprised of two parts: general creativity and specific creativity. A total CPS score was calculated by summing the general and specific components.

The Sense of Agency Rating Scale (SOARS) measures two aspects of agency: the sense that events that occur are externally generated, and the sense that actions occurring easily and spontaneously.

At the conclusion of the study, participants were asked to give Likert ratings for the following questions: how personally meaningful were their experiences microdosing during this study?, how spiritually significant were their experiences microdosing during this study?, and how their experience affected their current sense of well-being.

Microdosing characteristics

Ninety-eight participants sent 1792 daily reports throughout the study, including 489 reports of microdosing days. Of these reports, 3 were excluded due to high doses, and 8 were excluded due to concurrent use of other substances.

Participants reported microdosing with a wide range of substances, including common psychedelics such as LSD, psilocybin, and mescaline, as well as novel serotonergic psychedelics such as 4-HO-MET, dimethoxybromoamphetamine, 2C-C, 2C-D, 2C-E, and morning glory seeds.

Sixty-three participants completed baseline and post-study measures, and on average microdosed 5.0 times during the study. Of these, 20 had never microdosed prior to taking part in the study.

Daily ratings

We analysed daily ratings from 98 participants using a linear mixed-effects model. We determined the effect of microdosing on the day that participants ingested a dose and the two days following dosing.

The mean and standard deviation of daily ratings increased on dosing days and were significantly higher than baseline on the day following dosing. The conditional coefficient of determination (R2C) estimates give a relative indication of the variance explained by each model.

Long term measures

Our second set of analyses investigated changes across nine domains of psychological functioning from baseline to post study for 63 participants. The internal consistencies were good for all measures. We generated linear effects models to map the influence of prior experience and frequency of microdosing on each measure over the study period. There were three critical analyses in our model: the main effect of Time, and two interactions (Time x Experience and Time x Doses).

The results show that there were no obvious deviations from homoscedasticity or normality in the long term measures, and the three critical analyses were corrected using the Holm-Bonferroni adjustment.

We found that time had a main effect on a number of psychological measures, including mood, focus, mind wandering, absorption, and personality. There were no significant interactions between time, prior microdosing experience, or doses taken during the study period.

Microdosing may have influenced participants’ sense of agency, making actions feel more internally generated and spontaneous. Additionally, those who more regularly took microdoses scored higher in Conscientiousness.

Exploratory debrief questions

The majority of participants did not categorise their experience of microdosing during the study as particularly meaningful, but a minority did. Five participants claimed this experience was ‘among the 5 most meaningful experiences of my life’, and two claimed it was ‘the single most spiritually significant experience of my life’.

Participants overall reported that microdosing increased feelings of personal well-being, but this single item rating was not correlated with the post study QOLI Total score.

Study One discussion

Microdosing led to general increases in psychological functioning, which were not maintained in the days following dosing. However, two scores that could be related to increased capacities at work did show an effect two days following dosing.

This study focused on non-clinical effects of microdosing, and participants reported significant reductions in depression and stress ratings, as well as reduced mind wandering. These effects may be related to improved educational outcomes and greater levels of happiness.

Participants reported increased absorption, a trait associated with intense engagement with nature and aesthetic involvement with art. Furthermore, individuals with higher pre-existing levels of trait absorption were more likely to experience stronger effects from psychedelic substances.

Microdosing may have a similar effect to religious rituals, whereby regular experience of subtle alterations in consciousness increases sensitivity to future consciousness alterations.

Participants in this study reported an increase in trait neuroticism, which is inconsistent with the results showing reductions in standardised measures of mental health.

We did not find any changes in many domains of psychological functioning during six weeks of microdosing, including mindfulness, mystical experience, positive personality traits, creativity, sense of agency or overall quality of life.

Study Two

Some of the domains which did not change in Study One are commonly described in media stories on the effects of microdosing, whereas others that did change in Study One are not typically mentioned in media stories on microdosing. In Study One, participants were recruited from online communities that share positive experiences of microdosing. In Study Two, we investigated expectations held by members of online microdosing communities to see if they explained the experiences of microdosers in Study One.

We recruited a large sample from the same population as Study One and asked them to rate their microdosing expectations.


We recruited participants through the same online networks as Study One, and updated our study webpage so that individuals clicking on links we had previously posted online were shown information for Study Two. 263 participants completed the microdosing expectations questionnaire, and 152 reported never having microdosed previously.

Although both Study One and Study Two were drawn from the same population, there were some demographic differences between the two samples. These differences included age, country of residence, and gender.


We generated a new scale to index participants’ expectations about the effects of microdosing. The scale consisted of items that described the type of experience tapped by each subscale.

Participants’ frequency expectations were scored on a 3-point scale, and their confidence in each of these directional predictions was rated.


We calculated weighted expectation scores for each item using the R package Hmisc [102]. Results show that naive and experienced microdosers held consistent expectations about the effects of microdosing regardless of their personal experience.

We performed a one-sample weighted t-test to determine whether participants’ expectation scores differed from 0 for each subscale. Participants expected that all variables would change following microdosing.

We ranked participants’ expectations for each variable, based on the mean weighted expectation scores, and also showed the rank order of effects found in Study One. We found no evidence that participants’ expectations were related to the actual rankings of variables that did change in Study One.

Study Two discussion

Participants in Study Two expected that regular microdosing would decrease depression, stress, mind wandering, and increase absorption. However, in Study One, neuroticism increased.

Although not directly contradicted, participants’ predictions about which variables would change following microdosing were not supported by the evidence from Study One.

General discussion

This was exploratory research into people’s experience of and attitudes toward microdosing. It showed that microdosing led to improved mental health, altered attentional capacities, and increased neuroticism.

Study Two showed that people who are interested in microdosing hold strong beliefs that the practice can improve virtually all aspects of their lives.

We found clear changes in a small set of psychological variables, but not those that participants most expected to change. This suggests that the longer term changes identified were unlikely to be due to expectation.

Although there were clear short term changes following each microdose, the longer term changes were unrelated to the total number of doses participants ingested during the study period or to participants’ prior microdosing experiences.

Participants in Study One microdosed less often than recommended in most online protocols, and reported shorter term effects such as reduced mental distress and increased ability to become engaged in intense imaginative experiences.

Although the majority of participants’ comments were positive, there was a subset of comments that reflected unease about microdosing. This highlights the need for further research into the full range of microdosing effects (positive and negative).

Strengths, limitations and future directions

This study was a preliminary and exploratory study of microdosing, and relied on participants’ accuracy and honesty in their reports of doses and effects. It may also have been affected by sampling bias, and there was some concurrent use of higher dose psychoactive substances and non psychedelic substances.

This study investigated a wide range of psychological variables and used conservative adjustments to account for multiple comparisons within each domain. It suggests that the effects identified are worthy of further investigation in future confirmatory research with specific hypotheses.

Popular accounts of the effects of microdosing may not match the experience of long term microdosers, and promising avenues for future investigation are improved mental health, attentional capabilities, and neuroticism.


We thank Jim Fadiman for his pioneering work on this area, and Serje Robidoux for his invaluable analytical advice.


Authors associated with this publication with profiles on Blossom

Vince Polito
Vince Polito is a Senior Research Fellow in the School of Psychological Sciences, and a member of the Biomolecular Discovery Research Centre at Macquarie University.

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