From Academic Kids

Chemical name4-Phosphoryloxy-
Chemical formulaC12H17N2O4P
Molecular mass284.25 g/mol
CAS number520-52-5
Chemical structure of psilocybin

Psilocybin (4-phosphoryloxy-N, N-dimethyltryptamine) is a psychedelic alkaloid of the tryptamine family. It is present in many species of fungi, notoriously those of the genus Psilocybe, such as Psilocybe cubensis and Psilocybe semilanceata (Liberty Caps), but also reportedly isolated from a dozen or so other genera. Psilocybin-containing mushrooms are commonly called magic mushrooms or simply "shrooms". Effects of psilocybin generally resemble a shorter LSD trip.



Psilocybin is a prodrug that is converted into the pharmacologically active compound psilocin in the body by dephosphorylation. This chemical reaction takes place under strongly acidic conditions or enzymatically by phosphatases in the body. Psilocybin is a zwitterionic alkaloid that is soluble in water, moderately soluble in methanol and ethanol, and insoluble in most organic solvents. Psilocybin can be synthesized in the laboratory from psilocin by a two-step procedure, but this is rarely done since psilocin is the actual pharmacologically active compound.

Albert Hofmann was first to recognize the importance and chemical structure of the pure compounds psilocybin and psilocin, largely because he ate fractions isolated from the mushroom and subsequently named the active fractions. Hofmann's colleagues at the University of Delaware, who were funded by the Central Intelligence Agency, who were also trying to figure out why the mushrooms worked, could not figure out the active principles, despite interloping on at least one of Hofmann's visits to Mexico. Hofmann also had Roger Heim and R._Gordon_Wasson on his side.


In the mushroom psilocybin is distributed fairly evenly throughout the entire fruiting body, with the exception of the spores which are completely free of psilocybin and psilocin. The total potency varies greatly between species and even between specimens of the same batch of one species. There should be no drastic difference in potency between stems and caps from the same batch. Younger, smaller mushrooms are relatively higher in alkaloids and have a milder taste than larger, mature mushrooms. Mature mycelium contains small amounts of psilocybin, though one generally does not eat or otherwise process it. Young mycelium (recently germinated from spores) does not contain appreciable amounts of psilocybin. Most species of hallucinogenic mushrooms also contain small amounts of the psilocybin analogs baeocystin and norbaeocystin.


Psilocin, the active metabolite of psilocybin, acts by interaction with neurotransmitter receptors on nerve cells in the brain where it mimicks the action of serotonin (5-HT). Specifically, psilocin is a post-synaptic 5-HT2A receptor agonist. This is the same mechanism of action as for the other hallucinogens like LSD, mescaline, or 2C-B. LSD and psilocybin show cross-tolerance — after taking one of these substances, the brain quickly develops a tolerance to it, and taking another dose of either soon afterward will require more than usual to achieve the desired effects.


Psilocybin has been studied as a treatment for several disorders.

In the US, an FDA-approved study supported by Multidisciplinary Association for Psychedelic Studies (MAPS) began in 2001 to study the effects of psilocybin on patients with obsessive-compulsive disorder. MAPS has also proposed studying psilocybin's potential application for the treatment of cluster headaches based on anecdotal evidence presented to them by a cluster headache sufferer.


Psilocybin has a fairly high LD50, signifying very low toxicity -- more than half that of caffeine when administered intravenously in rats. Death from psilocybin intake alone is unknown at most recreational or medicinal levels.


Psilocybin is absorbed through the lining of the mouth and stomach. Effects begin 20-45 minutes after ingestion of psilocybin-containing mushrooms, and last from 2-6 hours depending on dose, species, and individual metabolism. If mushrooms are chewed and held in the mouth, or taken as mushroom tea, effects begin slightly sooner and are usually noticeable within 15 minutes.

At low doses, hallucinatory effects occur, including walls that seem to breathe, a vivid enhancement of colors and the animation of organic shapes. At higher doses, experiences tend to be less social and more entheogenic, often catalyzing intense spiritual experiences.

The effects are often pleasant, even ecstatic, including a deep sense of connection to others, and a general feeling of connection to nature and the universe. However, as with all psychedelic chemicals, not all experiences are positive. This is especially true when they are taken with other drugs, during times of mental instability, or by people with psychoemotional problems. In such situations, "bad trips" are much more likely to occur. Anxiety, frightening hallucinations, confronting (symbolically or literally) past or deep-seated internal conflicts, and feelings of permanent disconnection from reality and the Self can be quite intense and cause panic. The possibility of such experiences can be mitigated by being cognizant of one's set and setting.

A very small number of people are unusually sensitive to psilocybin's effects, where doses as little as 0.25 grams of dried Psilocybe cubensis mushrooms (normally a threshold dose of around 2 mg psilocybin) can result in effects usually associated with medium and high doses. Likewise, there are some people who require relatively high doses of psilocybin to gain low-dose effects. Individual brain chemistry and metabolism plays a large role in determining a person's response to psilocybin.

Psilocybin is probably metabolized mostly in the liver, but is also broken down by the enzyme monoamine oxidase (MAO). MAOIs can roughly double the potency of psilocybin — people who are taking an MAOI for a medical condition (or are seeking to potentiate the mushroom experience) must be careful.

Mental and physical tolerance to psilocybin builds and dissipates quickly. Taking psilocybin more than three or four times in a week (especially two days in a row) can result in diminished effects. Tolerance dissipates after a few days, so frequent users often keep doses spaced five to seven days apart to avoid the effect.


Spores of Psilocybe mushrooms can be legally purchased from several mail order sources; however cultivation and consumption of the mushrooms are illegal in many jurisdictions.

Internationally, psilocybin is a Schedule I drug under the Convention on Psychotropic Substances. Parties to the treaty are required to restrict use of the drug to medical and scientific purposes.

  • In Japan, it was legal to possess and sell psilocybin mushrooms until June 2002. Possession was made illegal in 2002, possibly in preparation for the World Cup and in response to a widely reported case of mushroom poisoning.
  • In Denmark, sale, possession and consumption of psilocybine/psilocine mushrooms were legal up until 2002, where the governmental purge of what they called "designer drugs" outlawed them along with a number of other hallucinogens and empathogens.
  • In the United States, psilocybin and psilocybe mushrooms are regulated under DEA Schedule 1, making them illegal to possess under federal law. (Researchers and their subjects are granted exemptions by the DEA.) Under state law, it is illegal to possess psilocybin and psilocybin mushrooms in all states except Florida and New Nexico. In Florida, a court decision ruled that "wild" psilocybin mushrooms themselves are not illegal to possess as they are not mentioned by law. Since Florida has not decided at this time to change its laws on this matter, they remain presumptively legal. New Mexico appeals court ruled on June 16, 2005, that growing psilocybin mushrooms for personal consumption could not be considered "manufacturing a controlled substance" under state law. [Growing hallucinogenic mushrooms not illegal, state appeals court rules (] Psilocybin mushroom spores are legal to sell and possess in every state except California, Idaho, and Georgia.[1] (
  • In the United Kingdom, possession of unprocessed mushrooms is illegal. As a result of new laws unveiled on January 18, 2005, psilocybin-containing mushrooms are now classified as a "Class A" substance under UK law.
  • In the Netherlands, possession of unprocessed mushrooms is not illegal. However, when prepared, the product (dried mushrooms, tea or powder) may be construed as illegal. Because of this there are a lot of drug shops selling fresh mushrooms in the Netherlands, especially in Amsterdam.
  • In Norway, possession of the indigenous Liberty cap (Psilocybe semilanceata) has been illegal since 1977. In 2004, all mushrooms containing psilocybin and psilocin, and specifically Psilocybe cubensis, were outlawed.


External links

  • The Vaults of Erowid ( Psilocybin mushrooms
  • Erowid ( Psychedelic crisis FAQ
  • Erowid ( page on various psychoactive LD50s
  • The Mechanisms of Mind-Manifesting Mushrooms (
  • MAPS ( Psilocybin research
  • Shroomery ( Dosage calculator
  • Science & Consciousness Review ( The Neurochemistry of psychedelic experience
  • Good Drugs Guide (
  • Clusterbusters ( Psilocybin as cluster headache treatment
  • The comedian Bill Hicks has used his psilocybin experiences as themes for his act.
  • Terence McKenna has written extensively on the psychopharmacology of psilocybin, as well as authoring a popular and authoritative growing guide, written under the pseudonym Oss and Oeric.

Template:Tryptaminesde:Psilocybin io:Psilocibino nl:Psilocybine pl:Psylocybina sv:Psilocybin


Academic Kids Menu

  • Art and Cultures
    • Art (
    • Architecture (
    • Cultures (
    • Music (
    • Musical Instruments (
  • Biographies (
  • Clipart (
  • Geography (
    • Countries of the World (
    • Maps (
    • Flags (
    • Continents (
  • History (
    • Ancient Civilizations (
    • Industrial Revolution (
    • Middle Ages (
    • Prehistory (
    • Renaissance (
    • Timelines (
    • United States (
    • Wars (
    • World History (
  • Human Body (
  • Mathematics (
  • Reference (
  • Science (
    • Animals (
    • Aviation (
    • Dinosaurs (
    • Earth (
    • Inventions (
    • Physical Science (
    • Plants (
    • Scientists (
  • Social Studies (
    • Anthropology (
    • Economics (
    • Government (
    • Religion (
    • Holidays (
  • Space and Astronomy
    • Solar System (
    • Planets (
  • Sports (
  • Timelines (
  • Weather (
  • US States (


  • Home Page (
  • Contact Us (

  • Clip Art (
Personal tools