Psilocybin vs Psilocin
Psilocybin and psilocin are two linked substances. This page explains how the body turns one into the other, what each one is, and how they are listed under US federal law.
Content last updated . This page has not been medically reviewed.
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This page is education only. It gives no amounts, no sourcing and no preparation advice. It answers one question: how are psilocybin and psilocin different, and why do people mix them up?
The short answer
Psilocybin and psilocin are two chemical forms in one chain. Psilocybin is a prodrug, meaning it is mostly inactive until the body changes it. An enzyme called alkaline phosphatase removes part of the molecule and makes psilocin, the active form. [1] Both are described as acting on the serotonin 2A receptor. [1]Side by side
| Psilocybin | Psilocin | |
|---|---|---|
| Role | Prodrug, changed by the body | Active metabolite, the form that acts |
| Where it is found | In fungi, mainly the genus Psilocybe | In fungi, and made in the body from psilocybin |
| Used as the study drug in trials | Yes, in clinical trials we read | We found no trial that gave psilocin itself |
| US federal listing | Schedule I | Schedule I, listed as "psilocyn" |
Psilocybin, psilocin and related compounds typically occur in most species of Psilocybe. [2] The same source notes that the amount in individual fruiting bodies is highly variable, so no single figure describes a "typical" mushroom. [2]
What the body does with them
A systematic review of 19 publications (12 unique datasets) reported that after psilocybin is given by mouth, it is rapidly absorbed and changed to psilocin. Psilocin's terminal half-life across studies was 1.23 to 4.72 hours. [3] Only 1.5 to 3.4% of the dose was found as psilocin in urine, because most is changed into other substances. [3] The main urinary metabolite is psilocin-O-glucuronide. [1] Another review adds that people differ considerably in how they respond. [1]These figures come from clinical studies of psilocybin. They are not a guide to how any mushroom or product will act.
Evidence labels used here
We use plain labels: approved medicine, promising but limited, insufficient evidence, and Proper evidence not found when we looked and found nothing usable.- Psilocybin as a depression treatment: promising but limited. The US National Institute on Drug Abuse notes that FDA has granted Breakthrough Therapy designation to two formulations of psilocybin under study. That designation is not an approval. [4]
- Psilocin as a separate treatment: Proper evidence not found. We checked PubMed pharmacokinetic and clinical reviews.
Risks
A meta-analysis of six randomized trials (528 participants) of single therapeutic-dose psilocybin found headache, nausea, anxiety, dizziness and raised blood pressure were more common than with comparison treatments, and the effects resolved within 48 hours. [5] Those were supervised trials in people with depression or anxiety, so they do not describe use elsewhere. NIDA states there are no safety data for psilocybin in pregnancy. [4]Legal status
Not legal advice; laws change. In the United States, 21 CFR 1308.11 lists both psilocybin and "psilocyn" in Schedule I (eCFR, read 2026-10-22). [6] Other countries: not verified. See psychedelic legal status by country.Related guides
For each compound alone see psilocybin and psilocin. For the mushrooms themselves see psilocybin mushrooms.Frequently asked questions
Is psilocin stronger than psilocybin?
We do not compare strength or give equivalents. What the sources show is that psilocybin is changed into psilocin, which is the active form. [1]
Do mushrooms contain psilocybin or psilocin?
Psilocybe fungi typically contain psilocybin and psilocin together with related compounds. [2]
Which one do clinical trials use?
The trials we read give psilocybin. For example, the safety meta-analysis covered randomized trials of psilocybin. [5]
Are both illegal in the United States?
Both are listed in Schedule I of the federal list we read. Other places differ, and we have not verified them. [6]
References
- Dinis-Oliveira RJ. Metabolism of psilocybin and psilocin: clinical and forensic toxicological relevance. Drug Metab Rev. 2017;49(1):84-91. Read 2026-10-22 (abstract on PubMed).
- Gotvaldova K et al. Stability of psilocybin and its four analogs in the biomass of the psychotropic mushroom Psilocybe cubensis. Drug Test Anal. 2021;13(2):439-446. Read 2026-10-22 (abstract on PubMed).
- Otto ME et al. Clinical Pharmacokinetics of Psilocin After Psilocybin Administration: A Systematic Review and Post-Hoc Analysis. Clin Pharmacokinet. 2025;64(1):53-66. Read 2026-10-22 (abstract on PubMed).
- National Institute on Drug Abuse, Psychedelic and Dissociative Drugs. Read 2026-10-22.
- Yerubandi A et al. Acute Adverse Effects of Therapeutic Doses of Psilocybin: A Systematic Review and Meta-Analysis. JAMA Netw Open. 2024;7(4):e245960. Read 2026-10-22 (abstract on PubMed).
- US Electronic Code of Federal Regulations, 21 CFR 1308.11 Schedule I. Read 2026-10-22.