Psilocybin is a naturally occurring psychedelic compound found in over 200 species of mushrooms. With the chemical formula C12H17N2O4P, it belongs to a class of compounds called tryptamines. Psilocybin itself is actually inactive and serves as a prodrug, meaning it must be converted by the body into its active form, psilocin, to produce psychoactive effects. This conversion process is crucial for understanding how psilocybin affects the human body.
Once ingested, psilocybin undergoes a crucial metabolic transformation in the human body. The process, called dephosphorylation, occurs primarily in the digestive system where specific enzymes remove the phosphate group from the psilocybin molecule. This conversion typically takes place within 20 to 40 minutes after ingestion. The resulting compound, psilocin, is the true active ingredient responsible for all psychoactive effects. This two-step process explains why there is often a delay between consuming psilocybin mushrooms and experiencing their effects.
Psilocin exerts its effects by interacting with the brain's serotonin system. It acts as an agonist, meaning it binds to and activates serotonin receptors, particularly the 5-HT2A receptor subtype. This receptor is found throughout the brain, especially in areas responsible for perception, mood, and cognition. While psilocin mimics serotonin's action, it binds with different patterns and intensities, leading to altered neural communication. The structural similarity between psilocin and natural serotonin allows this molecular mimicry, but the subtle differences in binding create the unique psychoactive effects associated with psilocybin.
Psilocin's effects on serotonin receptors translate into profound changes in brain network connectivity. The compound disrupts normal communication patterns between brain regions while simultaneously increasing neural plasticity. Key areas affected include the prefrontal cortex, responsible for executive function and decision-making, the visual cortex, which processes sensory information, and the default mode network, associated with self-referential thinking. Under psilocin's influence, there is increased cross-talk between normally separate brain networks, leading to altered information processing and the characteristic changes in perception and consciousness. Notably, the default mode network shows significantly reduced activity, which may contribute to the dissolution of ego boundaries often reported during psychedelic experiences.
Beyond its effects on the brain, psilocin produces a range of physiological changes throughout the body. Cardiovascular effects include increased heart rate and elevated blood pressure, which typically begin during the onset phase. Neurological changes are evident in pupil dilation, which can be quite pronounced, and alterations in temperature regulation, leading to feelings of warmth or coolness. Gastrointestinal effects, particularly nausea, are common during the early phase as the body processes the compound. The timeline of effects follows a predictable pattern: onset occurs within 30 to 60 minutes after ingestion, peak effects are reached at 2 to 3 hours, and the total duration spans 4 to 6 hours. These physical effects accompany the psychological changes and are important considerations for understanding psilocybin's comprehensive impact on human physiology.