NutriStack
Psilocybin and St. John's Wort, a caution.
St. John's Wort has serotonergic and weak monoamine-oxidase-modulating activity, so combining it with the serotonergic psychedelic psilocybin raises the theoretical risk of excessive serotonergic effects and unpredictable response.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- Psilocybin and St. John's Wort
- Pair type
- Caution
- Evidence (highest tier)
- Emerging
- Source citations
- 2 sources
- Stack Score effect
- −5 to your Stack Score (per scored caution row).
- Scope
- Supplement × Supplement
- Last verified
- May 30, 2026
Caution · Emerging evidence
Caution
What is happening. St. John's Wort has serotonergic and weak monoamine-oxidase-modulating activity, so combining it with the serotonergic psychedelic psilocybin raises the theoretical risk of excessive serotonergic effects and unpredictable response.
Mechanism. Psilocin acts as a serotonin 5-HT2A receptor agonist while St. John's Wort increases synaptic serotonin and has weak MAO-inhibiting constituents, creating potential for additive serotonergic activity.
Recommendation. Do not combine without medical guidance. Anyone using St. John's Wort should seek medical advice before considering psilocybin.
Stack Score
How this pair moves the number.
Effect on the composite score
If both Psilocybin and St. John's Wort are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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