These substances were used as a catalyst for ritual religious experience, but also used at lower doses as an aphrodisiac, to reduce hunger, inspire courage, nullify pain, and to treat ailments such as gout and syphilis. Anthropological reports indicate that many traditional cultures incorporated use of psychedelic plants such as peyote, morning glory seeds and psilocybin containing mushrooms into many aspects of daily life. The earliest occurrence of microdosing is unknown. Microdosing is thus a curious phenomenon: on the one hand advocates deny experiencing the alterations in consciousness that characterise typical doses, yet claim significant psychological benefits from regular use. ĭespite the reported lack of acute effects of microdosing, proponents claim a wide variety of psychological and social benefits from regular microdosing, including increases in vitality, creativity, productivity, social ability, focus, analytic thinking, positive mood, memory, mindfulness and general wellbeing. Most popular press stories on microdosing have mentioned this three day cycle. The idea behind this regimen is that there may be a residual effect from each microdose that lasts one to two days afterwards. One common schedule is to microdose every three days. People follow a variety of different schedules when microdosing, sometimes taking a dose each day but much more frequently interspersing dosing days with rest days. In other words, when microdosing there are only minimal identifiable acute drug effects. That is, individuals aim to identify a dose at which they do not feel ‘high’. Microdosing is frequently described as involving a ‘sub-threshold’ dose. Individuals who have taken psychedelics typically describe pronounced changes in visual and auditory perception, accompanied by vivid imaginative experiences and intense emotions. Psychedelics have typically been associated with marked alterations in cognition, affect, perception, and neurophysiology. People microdose using a wide range of different substances, although LSD and psilocybin are the most commonly discussed in online forums. So, for example, a microdose of lysergic acid diethylamide (LSD) might be 6–25 micrograms, or a microdose of psilocybin might be. There has been little peer-reviewed research on microdosing but there are numerous blogs and online communities that discuss the practice, with detailed guides to methods and anecdotal reports of outcomes (e.g., Typical doses can be as small as one twentieth of a typical recreational dose, sometimes even less. Microdosing refers to the practice of ingesting a very low dose of a psychedelic substance. The current results suggest that dose controlled empirical research on the impacts of microdosing on mental health and attentional capabilities are needed. Notably, the effects believed most likely to change were unrelated to the observed pattern of reported outcomes. All participants believed that microdosing would have large and wide-ranging benefits in contrast to the limited outcomes reported by actual microdosers. 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. 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. 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. 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. We tracked the experiences of 98 microdosing participants, who provided daily ratings of psychological functioning over a six week period. In Study One we conducted a systematic, observational investigation of individuals who microdose. 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. Individuals who microdose report minimal acute effects from these substances yet claim a range of long-term general health and wellbeing benefits. 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.