VCVITAMINS/CHART

The Bottom Line

Avoid taking L-Tryptophan and St. John's Wort together without specialist advice because their effects may overlap in a potentially harmful way.

VERDICT

L-Tryptophan and St. John's Wort together need specialist review rather than routine self-supplementation. Avoid combining these serotonin-related supplements without specialist supervision. Taking them a few hours apart does not reliably prevent serotonin toxicity; agitation, fever, tremor, or muscle rigidity need urgent medical attention.

Avoid together Limited evidence
01 / MECHANISM

How They Interact

L-tryptophan contributes to protein synthesis and is a precursor for serotonin and melatonin. St. John's wort can induce drug-metabolizing enzymes and transporters, reducing the exposure to many medicines. These individual roles do not establish that L-Tryptophan improves the absorption or effectiveness of St. John's Wort, or vice versa. Direct clinical evidence for this particular combination is limited. Avoid combining these serotonin-related supplements without specialist supervision. Taking them a few hours apart does not reliably prevent serotonin toxicity; agitation, fever, tremor, or muscle rigidity need urgent medical attention. St. John's wort has a substantial medicine-interaction burden. The absence of a documented direct interaction with the other supplement does not clear the combination for someone taking prescriptions, and spacing doses does not reverse enzyme induction.

02 / BEST PRACTICES

How To Take Them

Do not begin this combination as a self-directed mood or sleep stack. Ask your prescriber or pharmacist to review both supplements and all medicines, including nonprescription cough and migraine products. Taking the ingredients with different meals or several hours apart does not reliably remove the concern. If you already use both, seek advice before making changes to prescribed treatment; urgent symptoms such as fever, agitation, or muscle rigidity need prompt medical assessment.

03 / FORM MATTERS

Form & Quality Differences

A standalone tryptophan product differs from a sleep blend containing 5-HTP or melatonin. Hyperforin content varies, so one extract's interaction profile cannot be assumed for another.

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Practical Tips

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Frequently Asked Questions

Who Should Be Careful Avoid combining these serotonin-related supplements without specialist supervision. Taking them a few hours apart does not reliably prevent serotonin toxicity; agitation, fever, tremor, or muscle rigidity need urgent medical attention. St. John's wort has a substantial medicine-interaction burden. The absence of a documented direct interaction with the other supplement does not clear the combination for someone taking prescriptions, and spacing doses does not reverse enzyme induction. Combining tryptophan with serotonergic medicines can be hazardous; it may also cause drowsiness. St. John's wort has serious interactions with antidepressants, contraceptives, transplant medicines, and many other drugs.
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Sources & Further Reading

  1. Memorial Sloan Kettering Cancer Center Memorial Sloan Kettering — 5-HTP
  2. NCCIH NCCIH — St. John's Wort
  3. NCCIH NCCIH — Using Dietary Supplements Wisely

Reviewed by Caroline M. on October 20, 2026 for accuracy against the sources listed above. This page is educational and is not a substitute for professional medical advice.

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The matrix has 86 supplements and 7310 pairwise interactions. Click any cell to see the full breakdown.

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