Psilocybin is the active compound in sacred mushrooms and truffles. The chemical name of psilocybin is O-phosphoryl-4-hydroxy-N,N-dimethyltryptamine. After ingesting psilocybin your body quickly transforms it into psilocin (4-hydroxy-N,N-dimethyltryptamine), a very similar molecule to serotonin, which gives the actual psychedelic effect. By mimicking serotonin it stimulates the 5-HT2A receptor in the prefrontal cortex of your brain. Stimulating brain activity, growth and connections.