Psilocybin comes from certain types of psilocybe mushrooms. Psilocybin is metabolized in the body to the active drug psilocyn, also present in many of the same mushrooms.

What is its effects on the body?

The physical effects include: Nausea, vomiting, muscle weakness, and lack of coordination. The psychological consequences of psilocybin use include hallucinations and an inability to discern fantasy from reality. Panic reactions and a psychotic-like episode also may occur, particularly if a user ingests a high dose.

What are its overdose effects?

Longer, more intense “trip” episodes, challenging experiences (physical and emotional), psychosis, and possible death.

Abuse of psilocybin mushrooms could also lead to poisoning if one of the many varieties of poisonous mushrooms is incorrectly identified as a psilocybin-containing mushroom.

The effects of psilocybin mushrooms come from psilocybin and psilocin. When psilocybin is ingested, it is broken down by the liver in a process called dephosphorylation. The resulting compound is called psilocin, responsible for the psychedelic effects.^[31] Psilocybin and psilocin create short-term increases in tolerance of users, thus making it difficult to misuse them because the more often they are taken within a short period, the weaker the resultant effects are.^[32] Psilocybin mushrooms have not been known to cause physical or psychological dependence (addiction).^[33] The psychedelic effects appear around 20 minutes after ingestion and can last up to 6 hours. Physical effects may occur, including nausea, vomiting, euphoria, muscle weakness or relaxation, drowsiness, and lack of coordination.

As with many psychedelic substances, the effects of psychedelic mushrooms are subjective and can vary considerably among individual users. The mind-altering effects of psilocybin-containing mushrooms typically last from three to eight hours, depending on dosage, preparation method, and personal metabolism. The first 3–4 hours after ingestion are typically referred to as the ‘peak’—in which the user experiences more vivid visuals and distortions in reality. The effects can seem to last much longer for the user because of psilocybin’s ability to alter time perception.^[34]