What kind of interaction is it?

Conflict: combining the two is generally not recommended without clinician oversight.

Is this interaction backed by published research?

Yes. NutriStack lists 2 citation rows for the MDMA + St. John's Wort pair, each linking to PubMed by PMID where available. Full sourcing methodology at https://nutristackapp.com/methodology/interactions.

Interaction databaseSupplement × SupplementReviewed May 2026

MDMA and St. John's Wort, a conflict.

Q: Can I take MDMA and St. John's Wort together?

Generally not recommended together. MDMA and St. John's Wort have a documented conflict. St. John's Wort both adds to serotonergic load and induces drug-metabolizing enzymes, so combined with MDMA it can raise serotonin syndrome risk while also unpredictably altering MDMA blood levels.

Q: How does this affect a NutriStack Stack Score?

-10 to your Stack Score per scored conflict row.

St. John's Wort both adds to serotonergic load and induces drug-metabolizing enzymes, so combined with MDMA it can raise serotonin syndrome risk while also unpredictably altering MDMA blood levels.

2 primary source citations. Moderate evidence. Last verified May 30, 2026.

Open the interaction checker →Read the methodology

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.

Sourcing standards·Evidence tiers

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: MDMA and St. John's Wort
Pair type: Conflict
Evidence (highest tier): Moderate
Source citations: 2 sources
Stack Score effect: −10 to your Stack Score (per scored conflict row).
Scope: Supplement × Supplement
Last verified: May 30, 2026

Conflict · Moderate evidence

Conflict

What is happening. St. John's Wort both adds to serotonergic load and induces drug-metabolizing enzymes, so combined with MDMA it can raise serotonin syndrome risk while also unpredictably altering MDMA blood levels.

Mechanism. St. John's Wort has serotonergic activity that adds to MDMA's serotonin release, and it induces CYP3A4 and CYP2C9 and P-glycoprotein, which can shift MDMA and metabolite exposure in unpredictable ways.

Recommendation. Do not combine. Seek medical advice, and watch for signs of serotonin excess such as agitation, sweating, tremor, and rapid heartbeat.

Sources (2)

Stack Score

How this pair moves the number.

Effect on the composite score

If both MDMA and St. John's Wort are in the same stack, this pair applies −10 to your Stack Score (per scored conflict row).

The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.

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