Psilocybin
Onset 30 min · peak 90–120 min · total 5–6 hours
Mechanism
Psilocybin is rapidly dephosphorylated to psilocin in the body. Psilocin is a partial agonist at the 5-HT2A receptor — the same receptor that mediates the subjective effects of LSD and DMT. The effect onset is ~30 minutes oral, peak around 90 minutes, and total duration ~5–6 hours.
Experience spectrum
Sensory enhancement, mild visual texture, gentle mood lift, normal cognition. Functional. Often called the 'museum dose'.
Clear visual distortion, strong emotional resonance, time dilation, music-driven introspection. Conversation possible but the experience demands attention.
Ego dissolution becomes possible. Intense visuals (eyes-closed imagery), profound shifts in self-perception, mystical-type experience reported by ~half of high-dose subjects (Griffiths 2011). Not for first-timers, not for unsupervised solo settings.
Risks and contraindications
- ▸Anxiety and panic at higher doses, especially for inexperienced users in unfamiliar settings.
- ▸Transient blood pressure and heart rate elevations — minor in healthy adults but a concern with cardiac history.
- ▸Hard contraindication with lithium (seizure risk in case reports).
- ▸May trigger or prolong psychotic episodes in those with personal or family history of psychosis or bipolar I.
- ▸SSRIs/SNRIs reduce subjective effects — do not interpret a weak experience as a 'low dose'.
Set & setting
- ▸Avoid first-time use alone. A trusted, sober person nearby massively reduces risk and panic.
- ▸Empty stomach (3+ hours since last meal) makes onset faster and peak sharper. Light food can blunt nausea.
- ▸Have a quiet space and a comfortable lying-down option for the peak.
- ▸Avoid major life-context decisions during or for 24 hours after.
Sources
- Garcia-Romeu, Barrett, Carbonaro, Johnson, Griffiths (2021) — Optimal dosing for psilocybin pharmacotherapy: Considering weight-adjusted and fixed dosing approachesJournal of PsychopharmacologyPooled analysis of 10 Hopkins studies (2001–2018) finds body weight had no consistent effect on subjective response across 49–113 kg at 20–30 mg/70kg. Justifies a gentle (not strong) weight-adjustment factor.
- Hasler, Grimberg, Benz, Huber, Vollenweider (2004) — Acute psychological and physiological effects of psilocybin in healthy humans: a double-blind, placebo-controlled dose-effect studyPsychopharmacologyClassic 8 / 14 / 22 mg per 70 kg ladder. Foundation for our low/medium/high band cutoffs in pure psilocybin.
- Griffiths, Johnson, Richards, Richards, McCann, Jesse (2011) — Psilocybin occasioned mystical-type experiences: immediate and persisting dose-related effectsPsychopharmacologyDose-effect on subjective intensity at 5 / 10 / 20 / 30 mg/70 kg; supports our medium/high band ranges.
- Spriggs, Giribaldi, Carhart-Harris et al. (2023) — Body mass index (BMI) does not predict responses to psilocybinJournal of PsychopharmacologyImperial College finding that BMI does not predict subjective psilocybin response. Reinforces a conservative, gentle weight factor for psilocybin.