Editorial interaction review
Human interaction studies and authoritative safety guidance report that St. John's wort can alter exposure to hormonal contraceptive components. This is a medication-specific safety issue, not a theoretical supplement-stack overlap.
Why it is flagged
Human interaction studies and authoritative safety guidance report that St. John's wort can alter exposure to hormonal contraceptive components. This is a medication-specific safety issue, not a theoretical supplement-stack overlap.
Interaction mechanism
The main interaction pathway is induction of drug-metabolizing systems, especially CYP3A-related metabolism, which can reduce exposure to some contraceptive components.
The magnitude depends on the contraceptive formulation, St. John’s wort extract and hyperforin content, dose, duration, adherence, and individual metabolism. This page does not estimate pregnancy risk for an individual.
Primary studies are labeled separately from authoritative secondary guidance so the evidence chain is visible.
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