Psilocybin vs LSD

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This page is education only. It gives no amounts and no potency equivalence between psilocybin and LSD. Neither substance should be compared by amount.

Two classic psychedelics with different origins

The US National Institute on Drug Abuse (NIDA) describes psilocybin as found in certain types of mushrooms, and LSD as a lab-made substance derived from chemicals in fungi that grow on rye and other grains. [1] NIDA says psychedelic drugs such as psilocybin, LSD and DMT primarily affect 5-HT2A receptors, which are normally activated by serotonin. [1] That is a shared starting point, not proof the two are the same. Both are classic psychedelics, a group explained in classic psychedelics.

A direct trial in healthy volunteers

Evidence level: one small controlled comparison in healthy volunteers. It is not a treatment finding.

A double-blind, placebo-controlled crossover study in 28 healthy people compared LSD and psilocybin at two study amounts each, in five 25-hour sessions. [2] In that study:

• At study amounts that produced comparable effects, the two substances produced alterations of mind that did not differ beyond how long they lasted, and LSD had a clearly longer effect duration. [2]
• Psilocybin raised blood pressure more, and LSD raised heart rate more, though the overall cardiac strain measure was similar. [2]
• The authors concluded that differences in effects were tied to the amount used rather than to the substance. [2]

A second Basel trial in 32 healthy participants measured mean effect durations of 8.2 hours for LSD and 4.9 hours for psilocybin at the study amounts used. [3] Those durations depend on the amounts given in the trial, so they are not a general rule for any product.

Limits: healthy adults, a controlled setting, one site, short follow-up. Neither study tested treatment benefit.

Treatment evidence

Evidence labels: promising but limited for psilocybin in depression, insufficient evidence for LSD in the sources read here. NIDA reports FDA Breakthrough Therapy designation for two psilocybin formulations being studied for depression, which is not an approval. [1] For trial detail see psychedelics for major depressive disorder. Condition-by-condition results for LSD: Proper evidence not found in the sources we read for this page.

Risks and safety

A meta-analysis of adverse events in 214 studies of classic psychedelics (LSD, psilocybin, DMT, 5-MeO-DMT) found serious adverse events in no healthy participants and in about 4% of participants with pre-existing neuropsychiatric disorders, including worsening depression, suicidal behavior and psychosis. [4] Monitoring quality varied widely. [4] Among therapeutic-dose psilocybin trials, headache, nausea, anxiety, dizziness and raised blood pressure were more common than with comparators. [5]

A systematic review of drug-drug interactions found both weaker and stronger effects when classic psychedelics were combined with other drugs, with data thin for most combinations. [6] Interactions must be assessed substance by substance with a clinician. See psychedelic drug interactions and toxicology.

Legal status

Not legal advice; laws change. In the United States, 21 CFR 1308.11 lists lysergic acid diethylamide and psilocybin in Schedule I (eCFR, read 2026-10-22). [7] Other countries: not verified. See psychedelic legal status by country.

No winner

Neither is "better" or "safer". Which is studied, approved or legal depends on the purpose and place. For each compound alone see psilocybin and LSD.