NutriStack
Methylprednisolone and St. John's Wort, a conflict.
St. John's Wort products high in hyperforin induce CYP3A, and methylprednisolone is a CYP3A-sensitive steroid. This may lower methylprednisolone exposure and reduce anti-inflammatory or immunosuppressive effect, especially when steroid treatment is being used for an active flare or severe inflammation.
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
- Methylprednisolone 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 × Prescription
- Last verified
- May 30, 2026
Conflict · Moderate evidence
Conflict
What is happening. St. John's Wort products high in hyperforin induce CYP3A, and methylprednisolone is a CYP3A-sensitive steroid. This may lower methylprednisolone exposure and reduce anti-inflammatory or immunosuppressive effect, especially when steroid treatment is being used for an active flare or severe inflammation.
Mechanism. St. John's Wort induces intestinal and hepatic CYP3A4 through hyperforin-dependent pregnane X receptor activation. Increased CYP3A4 activity can accelerate clearance of CYP3A substrates such as methylprednisolone and lower systemic steroid exposure.
Recommendation. Avoid starting St. John's Wort during methylprednisolone therapy unless your prescriber approves. If you already take it, do not stop or start it abruptly without discussing steroid response and possible dose implications.
Sources (2)
- Whitten DL, Myers SP, Hawrelak JA, Wohlmuth H. The effect of St John's wort extracts on CYP3A: a systematic review of prospective clinical trials. Br J Clin Pharmacol. 2006;62(5):512-526. PMID 17010103
- Varis T, Kaukonen KM, Kivisto KT, Neuvonen PJ. Plasma concentrations and effects of oral methylprednisolone are considerably increased by itraconazole. Clin Pharmacol Ther. 1998;64(4):363-368. PMID 9797792
Stack Score
How this pair moves the number.
Effect on the composite score
If both Methylprednisolone 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.
Check your full routine
One pair was the worked example. NutriStack runs every pair in your stack at once.
Drop in your supplements and prescriptions and the public database surfaces every interaction, synergy, timing rule, and contraindication, every one linked to its primary source.