Psilocin
Psilocin is a naturally occurring psychedelic compound found in some fungi, including psilocybin-containing mushrooms. It is also the active molecule formed when the body converts psilocybin. Psilocin interacts with serotonin receptors in the brain and is associated with changes in perception, mood, and thought.
- Compound
- Psychedelic tryptamine
- In fungi
- Found in some mushroom species
- Related
- Active form of psilocybin
- Main target
- Serotonin receptors, including 5-HT2A
- U.S. status
- Federally Schedule I
What is psilocin?
Psilocin is a small organic molecule in the tryptamine family, a group of compounds with a structure related to the brain chemical serotonin. It occurs naturally in certain fungi, often alongside psilocybin. Unlike psilocybin, psilocin does not have a phosphate group attached. That chemical difference helps explain why the body can use psilocin directly, while it converts psilocybin into psilocin.
The compound is associated with psychedelic effects, including changes in sensory perception, emotions, and the sense of time. Experiences vary between people and situations; no single description captures them all. Psilocin is a subject of scientific study, but it is not an approved medicine in the United States. A research finding or biological effect should not be taken as proof that a compound is safe or suitable for personal use.
- 1Mushroom compounds
Some fungi contain psilocybin, psilocin, or both.
- 2Conversion
Enzymes remove a phosphate group from psilocybin in the body.
- 3Receptor interaction
Psilocin interacts with serotonin receptors, including 5-HT2A.
- 4Brain signaling
Receptor activity changes signaling linked with perception and mood.
How does psilocin form and act?
In the body, enzymes remove the phosphate group from psilocybin, producing psilocin. This conversion is one reason psilocybin is often described as a precursor, or prodrug, to psilocin. Some mushrooms contain psilocin itself as well as psilocybin, though their amounts vary. The compounds can also break down, and their levels in a mushroom are not reliably judged by appearance.
Psilocin interacts with several serotonin receptors, including the 5-HT2A receptor. Scientists connect activity at this receptor with many of the compound's psychedelic effects, though other receptors and brain processes may contribute. Serotonin itself is involved in many functions, so the effects are not a simple on-off switch. Research continues to explore how receptor activity relates to perception and experience.
Psilocin is active; psilocybin is converted into it.
It interacts with multiple serotonin receptor types.
It occurs in fungi and can also be made synthetically.
Editorial placement to help compare; not a measurement.
Where do people encounter psilocin?
People most often learn about psilocin through discussions of psilocybin-containing mushrooms, sometimes called magic mushrooms. Species in the genus Psilocybe are well known, but they are not the only fungi studied for these compounds. Psilocin may also be discussed in chemistry and neuroscience research, or in coverage of psychedelic policy and supervised service programs.
In the United States, psilocin and psilocybin are federally Schedule I controlled substances. State-level programs allow supervised access under specific rules in Oregon and Colorado; New Mexico's medical program is being set up. These programs do not change federal law, and their rules and availability differ. Laws can change, so check current official state information rather than assuming that access is permitted where you live.
| Psilocin | Psilocybin | Serotonin | |
|---|---|---|---|
| Type | Psychedelic tryptamine | Phosphate ester precursor | Natural signaling chemical |
| In mushrooms | Present in some species | Present in some species | Not a mushroom compound |
| Body role | Interacts with serotonin receptors | Converted into psilocin | Signals through its receptors |
| Key link | Active form of psilocybin | Precursor to psilocin | Related chemical structure |
What should people know about psilocin safety?
Psilocin can alter perception, judgment, and emotional responses, and experiences may be unsettling or confusing for some people. Physical effects can also occur. Effects are not reliably predictable from a mushroom's appearance, a name on a product, or another person's experience. This glossary is educational information, not a recommendation to use psilocin or a substitute for advice from a qualified professional.
Wild mushrooms can be difficult to identify, and toxic species may resemble non-toxic ones. Never eat a wild mushroom without expert identification. Blue discoloration on some mushrooms is not a reliable way to identify a species or determine safety. Products sold outside regulated settings may also have uncertain contents. For an urgent poisoning concern, contact emergency services or a poison control center.
- 1955
R. Gordon Wasson visited a mushroom ceremony in Mexico, drawing wider attention to psilocybin-containing mushrooms.
- 1958
Albert Hofmann and colleagues isolated psilocybin and psilocin from mushrooms.
- 1971
The United Nations adopted the Convention on Psychotropic Substances, which includes psilocybin and psilocin in Schedule I.
- 2020
Oregon voters approved Measure 109, creating a state framework for supervised psilocybin services.
How is psilocin connected to other mushroom topics?
Psilocybin and psilocin are closely related but not interchangeable names: psilocybin is converted into psilocin in the body, and psilocin is the form that directly interacts with relevant receptors. Baeocystin and aeruginascin are other mushroom compounds that appear in research about psilocybin-containing fungi. Their roles and effects are less established, so claims about them should be treated cautiously.
Psilocin also connects mushroom biology with neuroscience: fungi produce the compound, while researchers study its chemistry and interactions with the nervous system. Terms such as serotonin, 5-HT2A receptor, and psychedelic describe different parts of that picture. For mushroom identification, taxonomy, and safety, chemical discussions are no replacement for expert field identification. The presence of a compound cannot be confirmed just by looking at a mushroom.
Common questions about Psilocin
What is the difference between psilocin and psilocybin?
Psilocin and psilocybin are related compounds found in some fungi. Psilocybin has a phosphate group that the body removes to form psilocin. Psilocin is the active form that interacts with serotonin receptors. The names are related, but they refer to different molecules.
Is psilocin found in mushrooms?
Yes. Psilocin occurs in some fungi, including certain psilocybin-containing mushrooms. Its amount can vary between species and specimens, and it may occur alongside psilocybin. A mushroom's appearance cannot reliably confirm its species, contents, or safety.
How does psilocin affect the brain?
Psilocin interacts with several serotonin receptors, including 5-HT2A. Researchers associate activity at this receptor with many psychedelic effects, such as changes in perception and mood. The full picture is complex, and studies continue to examine how receptor activity relates to experience.
Is psilocin legal in the United States?
Psilocin is federally Schedule I in the United States. Oregon and Colorado have state programs allowing supervised access under specific rules, and New Mexico's medical program is being set up. State programs do not change federal law; check current official sources for details.
Related terms
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Sources and further reading
Written by the Pscilly editorial team and reviewed November 2026. Educational content only, not medical or legal advice. Pscilly does not sell psilocybin. Never eat a wild mushroom without expert identification.