Can You Take Levothyroxine and St. John's Wort Together?
No documented interaction was identified between levothyroxine and St. John's Wort in the sources reviewed.
See the full Levothyroxine page and St. John's Wort page for other reviewed interactions and reference information.
What the interaction means
NCCIH's St. John's Wort page names several drugs it can weaken (antidepressants, birth control, cyclosporine, anticonvulsants, heart medications, HIV drugs, cancer medications, warfarin, certain statins) -- levothyroxine is not among them. Levothyroxine's own extensive drug-interaction section does not name St. John's Wort either.
No documented interaction between Levothyroxine and St. John's Wort was identified in the authoritative sources reviewed. This is not a guarantee that no interaction exists for every dose, formulation, or individual -- it means the sources checked did not document one.
Practical context
NCCIH's St. John's Wort page and levothyroxine's FDA label were checked directly, full text, in both directions. Neither source names the other.
What the sources say
Last reviewed 2026-08-25
Medical information disclaimer: this information is general and educational. It does not diagnose conditions, prescribe treatment, or determine whether a combination is safe for you personally. Follow your prescription label and ask a pharmacist or clinician before starting, stopping, or combining products. Full disclaimer.
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