A microdose is when you’ve had just enough of a drug to have a subtle effect, but without the full experience. A cup of tea is a microdose of caffeine. One beer is a microdose of alcohol. And starting in the ‘60s, curious psychonauts... began experimenting with microdosing LSD and mushrooms.
Fadiman suggested that by taking a “microdose” of these drugs, you could get many of the beneficial creative and mindfulness effects, without the hallucinations or trippiness.