St Johns Wort and Tacrolimus

Supplement–drug interaction evidence from the TruthStack database.

SeverityHIGH
Evidence TierNeeds Verification
Interaction TypeANTAGONISTIC
Last Reviewed2026-02-10
Source Verification
Attestation METHODOLOGY_ATTESTED
Corpus manifest 26b2d684...
Last reviewed 2026-02-10
Primary source NCT03916380
Live attestation Query API — returns signed DAA ID per request
Data license CC BY 4.0

Summary

St. John's Wort induces CYP3A4 and P-glycoprotein, which are involved in tacrolimus metabolism and transport. This database flags that concurrent use is associated with reduced tacrolimus blood levels in published research, including studies in transplant patients. Subtherapeutic tacrolimus levels have been associated with risk of organ rejection. Discuss with your prescriber or pharmacist.

What We Don't Know

This interaction has needs verification evidence. Key gaps may include: direct clinical trial data for this specific combination, dose-response relationships, and long-term outcome data. Absence of evidence is not evidence of absence.

API Reference

GET https://api.truthstack.co/v1/check?c1=st%20johns%20wort&c2=tacrolimus

Open, unauthenticated. Returns JSON. Developer documentation

Sources

Primary: NCT03916380

Related Interactions

Bergamot + Tacrolimus Cbd + Tacrolimus Echinacea + Tacrolimus Goldenseal + Tacrolimus Grapefruit Extract + Tacrolimus Methylene Blue + St. John'S Wort Piperine + Tacrolimus Quercetin + Tacrolimus
What this page is and is not. TruthStack is an informational reference database that describes published pharmacological findings. It does not provide medical advice, diagnosis, or treatment recommendations. The information on this page reflects flags in our database and should not replace consultation with a qualified healthcare provider. Always discuss supplement-drug combinations with your prescriber or pharmacist.