Supplement stacks / St Johns Wort + Tacrolimus

Can You Take St Johns Wort with Tacrolimus?

St. John's Wort is known to interact with tacrolimus, potentially reducing its effectiveness by inducing cytochrome P450 enzymes. This could lead to inadequate immunosuppression, increasing the risk of transplant rejection. Caution is advised, and consultation with a healthcare provider is essential before combining these substances.

Safety at a glance
High risk
Safety score3/10

Conservative, AI-assisted reading of publicly available medical sources (NIH, Mayo Clinic, WebMD, Examine.com). Informational only — it can't account for your medications, conditions, or genetics.

Known interactions

St. John's Wort may decrease the plasma concentration of tacrolimus, leading to reduced immunosuppressive effects.

St. John's Wort

Generally considered safe for mild depression but can interact with many medications.

Typical dosage: 300-900 mg daily, divided into doses.

Common side effects:
  • Gastrointestinal upset
  • Fatigue
  • Allergic skin reactions
Warnings:
  • Consult healthcare provider before use, especially with tacrolimus.
  • May cause photosensitivity.
Tacrolimus

Effective immunosuppressant but requires careful monitoring of blood levels.

Typical dosage: 0.1-0.2 mg/kg/day, adjusted based on blood levels.

Common side effects:
  • Kidney toxicity
  • Hypertension
  • Increased risk of infections
Warnings:
  • Monitor kidney function and blood pressure regularly.
  • Avoid grapefruit juice.
Also commonly mentioned

These come up in questions about this combination — they are not part of the pair above.

Omega-3 Fatty Acids

Generally safe; may support cardiovascular health and reduce inflammation.

Typical dosage: 1000-3000 mg daily.

Common side effects:
  • Fishy aftertaste
  • Gastrointestinal discomfort
Warnings:
  • Consult healthcare provider if on anticoagulants.
  • Monitor for bleeding risk.

Vitamin D3

Essential for bone health; generally safe in recommended doses.

Typical dosage: 600-2000 IU daily, depending on blood levels.

Common side effects:
  • Nausea
  • Constipation
  • Fatigue
Warnings:
  • Monitor blood levels to avoid toxicity.
  • Consult healthcare provider for dosage adjustments.

Magnesium

Important for many bodily functions; generally safe but can cause diarrhea in high doses.

Typical dosage: 310-420 mg daily, depending on age and sex.

Common side effects:
  • Diarrhea
  • Nausea
  • Abdominal cramping
Warnings:
  • Consult healthcare provider if on diuretics or heart medications.
  • Monitor for interactions.
Timing

If St. John's Wort is deemed necessary, it should be taken at least 4 hours apart from tacrolimus to minimize interaction risks.

Watch out for
  • Avoid taking St. John's Wort with tacrolimus; consult healthcare provider for alternatives.
Frequently asked questions

Can you take St Johns Wort and Tacrolimus together?

St. John's Wort is known to interact with tacrolimus, potentially reducing its effectiveness by inducing cytochrome P450 enzymes. This could lead to inadequate immunosuppression, increasing the risk of transplant rejection. Caution is advised, and consultation with a healthcare provider is essential before combining these substances.

How safe is the St Johns Wort and Tacrolimus combination?

Our analysis of publicly available medical sources scores this combination 3/10 (high risk). This is an informational estimate, not medical advice — always confirm with a healthcare professional.

When should you take St Johns Wort and Tacrolimus?

If St. John's Wort is deemed necessary, it should be taken at least 4 hours apart from tacrolimus to minimize interaction risks.

What should you watch out for when combining St Johns Wort and Tacrolimus?

Avoid taking St. John's Wort with tacrolimus; consult healthcare provider for alternatives.

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Analysis generated August 11, 2026 · Sources include NIH, Mayo Clinic, WebMD, and Examine.com · How our analysis works