Psilocin

Psilocin
Clinical data
Other names	Psilocine; Psilocyn; Psilotsin; 4-Hydroxy-N,N-dimethyltryptamine; 4-Hydroxy-DMT; 4-Hydroxy-N,N-DMT; 4-HO-DMT; 4-OH-DMT; PSOH; PAL-153; PAL153; CX-59; CX59
Routes of; administration	Oral, intravenous
Drug class	Serotonergic psychedelic; Hallucinogen; Serotonin receptor agonist; Serotonin 5-HT2A receptor agonist
ATC code	None;
Legal status
Legal status	AU: S9 (Prohibited substance); BR: Class F2 (Prohibited psychotropics); CA: Schedule III; DE: Anlage I (Authorized scientific use only); NZ: Class A; UK: Class A; US: Schedule I; UN: Psychotropic Schedule I;
Pharmacokinetic data
Bioavailability	Oral psilocybin: 52.7 ± 20.4% (as psilocin)
Metabolism	Liver, other tissues:; • Demethylation and deamination (MAOTooltip monoamine oxidase); • Oxidation (ALDHTooltip aldehyde dehydrogenase); • Glucuronidation (UGTs)
Metabolites	• Psilocin-O-glucuronide; • 4-Hydroxy-indole-3-acetaldehyde; • 4-Hydroxyindole-3-acetic acid (4-HIAA); • 4-Hydroxytryptophol
Onset of action	15–40 minutes
Elimination half-life	Oral psilocybin: 2.3–3 hours (as psilocin); IVTooltip Intravenous injection psilocybin: 1.2 hours (as psilocin)
Duration of action	3–6 hours
Excretion	Urine (mainly as psilocin-O-glucuronide, 2–4% unchanged)
Identifiers
	IUPAC name 3-[2-(dimethylamino)ethyl]-1H-indol-4-ol;
CAS Number	520-53-6 ;
PubChem CID	4980;
IUPHAR/BPS	11291;
ChemSpider	4807 ;
UNII	CMS88KUW0G;
KEGG	C08312 ;
ChEBI	CHEBI:8613 ;
ChEMBL	ChEMBL65547 ;
CompTox Dashboard (EPA)	DTXSID5048899 ;
ECHA InfoCard	100.007.543
Chemical and physical data
Formula	C12H16N2O
Molar mass	204.273 g·mol−1
3D model (JSmol)	Interactive image;
Melting point	173 to 176 °C (343 to 349 °F)
	SMILES CN(C)CCc1c[nH]c2cccc(O)c12;
	InChI InChI=1S/C12H16N2O/c1-14(2)7-6-9-8-13-10-4-3-5-11(15)12(9)10/h3-5,8,13,15H,6-7H2,1-2H3 ; Key:SPCIYGNTAMCTRO-UHFFFAOYSA-N ;
	(verify)

Psilocin, also known as 4-hydroxy-N,N-dimethyltryptamine (4-HO-DMT), is a psychedelic drug and fungal alkaloid of the tryptamine and 4-hydroxytryptamine families. Along with its phosphate ester psilocybin, it is found in most species of psilocybin-containing mushrooms, such as Psilocybe cubensis and Psilocybe mexicana, and is the compound responsible for their hallucinogenic effects, although concentrations of psilocin are variably lower than those of psilocybin. The drug is taken orally and its effects include perceptual changes and visual effects, emotional changes, ego dissolution, time dilation, and mystical experiences, among others. Psilocybin, as well as synthetic acyl esters such as 4-AcO-DMT (psilacetin; O-acetylpsilocin) and 4-PrO-DMT (O-propionylpsilocin), are prodrugs of psilocin and have similar properties and effects.

Psilocin acts as a non-selective serotonin receptor agonist, including of the serotonin 5-HT_2A receptor among others. The drug produces its hallucinogenic effects specifically via activation of the serotonin 5-HT_2A receptor. However, other serotonin receptors, such as the serotonin 5-HT_1A and 5-HT_2C receptors, may also contribute to its effects. Notable analogues of psilocin include dimethyltryptamine (DMT), its positional isomer bufotenin (5-HO-DMT), its higher homologue 4-HO-MET (metocin), and others.

Psilocin and psilocybin were discovered via isolation from psilocybin-containing mushrooms by Albert Hofmann in 1958. This followed the Western re-discovery of psilocybin-containing mushrooms by Robert Gordon Wasson and Valentina Pavlovna Wasson in Mexico in 1955. Psilocin, in the form of psilocybin, psilocybin-containing mushrooms, and other prodrugs such as 4-AcO-DMT, is a widely used entheogen as well as recreational psychedelic drug. Psilocybin and psilocin became controlled substances in the United States and internationally under the United Nations in 1971. Since then, psilocin, as the active form of psilocybin, has become of interest for potential use in medicine to treat psychiatric disorders such as depression. Psilocybin was approved for such purposes in Australia in 2023 and is in late-stage clinical trials in the United States and other countries.