A "microdose" is an experimental way of administering a sub-psychoactive dose of a psychedelic substance. The dose is normally one-tenth to one-tenth and one-hundredth of the effective dose, often between 2-20 micrograms. It is designed to elicit subtle physiological, cognitive, and emotional changes in the user, without producing a full-blown psychedelic experience. The effects of microdosing may include increased creativity, increased energy, increased productivity, reduced anxiety and improved focus. These effects may be mild, but the overall cumulative effects have been reported to have a positive impact on one's physical and mental well-being.

See also: endocannabinoid system, nitric oxide, nitrous oxide, brain stem, vagal nerve