VCVITAMINS/CHART

The Bottom Line

Use caution with L-Glutamine and St. John's Wort together: the ingredients or formulations need review, and limited research does not establish the safety of this exact pair.

VERDICT

L-Glutamine and St. John's Wort together require more care than a neutral matrix label suggests. 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. The practical decision depends on the formulation, your medicines, and your response.

Use with caution Limited evidence
01 / MECHANISM

How They Interact

L-glutamine is an amino acid used by many tissues, including intestinal and immune cells. 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-Glutamine improves the absorption or effectiveness of St. John's Wort, or vice versa. Direct clinical evidence for this particular combination is limited. 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

Measure powder using the product's stated serving rather than an unmarked spoon. Have a pharmacist review all medicines before starting or stopping St. John's wort. There is no validated spacing interval that removes the concerns for this combination; reviewing the products and medicines is more useful than choosing an arbitrary time gap. If you miss a supplemental dose, resume the usual schedule instead of doubling the next dose; follow your prescriber's instructions for prescribed products.

03 / FORM MATTERS

Form & Quality Differences

A single-ingredient glutamine powder is easier to assess than a proprietary recovery blend. Hyperforin content varies, so one extract's interaction profile cannot be assumed for another.

05

Practical Tips

06

Frequently Asked Questions

Who Should Be Careful 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. Evidence for routine supplementation in healthy adults is limited; significant illness calls for individualized advice. St. John's wort has serious interactions with antidepressants, contraceptives, transplant medicines, and many other drugs.
08

Sources & Further Reading

  1. NIH ODS NIH ODS — Dietary Supplements for Exercise and Athletic Performance
  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.

WANT THE FULL PICTURE?

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

Back To The Vitamins Chart All St. John's Wort Interactions All L-Glutamine Interactions