All studies
Healthy volunteers (pharmacology) established evidence

Psychedelic effects of psilocybin correlate with serotonin 2A receptor occupancy and plasma psilocin levels

Key finding

The intensity of the subjective psychedelic experience tracked directly with 5-HT2A receptor occupancy and blood psilocin levels, confirming the receptor mechanism in living humans.

Institution
University of Copenhagen
Design
Within-subject pharmacology and PET study
Sample size
8 participants
Intervention
Oral psilocybin with PET imaging and plasma sampling
Year
2019
Condition
Healthy volunteers (pharmacology)
Limitations

Very small sample; PET occupancy modeling involves assumptions, and healthy volunteers may differ from clinical populations.

A mechanistic study that directly linked the felt intensity of a psilocybin experience to receptor occupancy and drug levels in the body — closing part of the gap between molecule and experience.

Summary written by MMI Editorial for clarity. Always consult the primary source for full methodology and results. Confidence rating reflects our assessment of evidence strength.