Co-administration of St. John's wort and hormonal contraceptives: a systematic review.
I take hormonal birth control — does St. John's wort make it less reliable for me, and if so what backup contraception should I be using?
Well-supported by good-quality research. how we score evidence
Caveat on this rating: Only four eligible studies existed, none of them powered to measure pregnancy rates, so the evidence establishes a mechanism and a warning signal rather than a quantified failure rate. Different St. John's wort products produced different degrees of interaction, which means a negative result for one brand does not clear the others.
In the United States St. John's wort is sold as a dietary supplement under DSHEA, which means it reaches the shelf without FDA review of efficacy, safety, or potency and the FDA can act only after a problem emerges. It has never been FDA-approved to treat depression or anything else.
A CDC and FDA systematic review found only four studies comparing combined oral contraceptives alone with the same pills taken alongside St. John's wort, but three of the four showed breakthrough bleeding, three showed reduced hormone exposure on pharmacokinetic measures, and one showed increased follicular growth and probable ovulation — meaning the pill may stop working. The one product that showed no significant pharmacokinetic difference was a low-hypericin preparation.
Worth asking
I take hormonal birth control — does St. John's wort make it less reliable for me, and if so what backup contraception should I be using?
Source
Co-administration of St. John's wort and hormonal contraceptives: a systematic review. — Berry-Bibee EN, Kim MJ, Tepper NK, Riley HE, Curtis KM. (2016)
Reputable peer-reviewed journal
Read the source: https://doi.org/10.1016/j.contraception.2016.07.010
DOI: 10.1016/j.contraception.2016.07.010
How this was scored
- Study design
- Systematic review of observational studies
- Funding
- Independently funded
- Published in
- Reputable peer-reviewed journal
- Sample size
- not recorded
- Preregistered
- No
- Conflicts disclosed
- Yes
- Independent of proponent
- Yes
- Retracted
- No
Read the full scoring rubric, including what it can't tell you.
Published August 19, 2026.
Where we put this study in context
Questions
How strong is the evidence behind this?
Resolv rates this source "strong evidence". Well-supported by good-quality research. It scores 73 out of 100 on our published rubric. One caveat travels with that badge: Only four eligible studies existed, none of them powered to measure pregnancy rates, so the evidence establishes a mechanism and a warning signal rather than a quantified failure rate. Different St. John's wort products produced different degrees of interaction, which means a negative result for one brand does not clear the others. The score is calculated from recorded facts about the source — study design, funding, publication venue, sample size, preregistration — not typed in by an editor.
What is the source for this?
Co-administration of St. John's wort and hormonal contraceptives: a systematic review. — Berry-Bibee EN, Kim MJ, Tepper NK, Riley HE, Curtis KM. (2016). Published in: Reputable peer-reviewed journal. DOI: 10.1016/j.contraception.2016.07.010. The full source is linked on this page so you can read it yourself.
Who paid for this research, and does that matter?
Study design: Systematic review of observational studies. Funding: Independently funded. The researchers were independent of whoever benefits from the result. Industry sponsorship is one of the most reliably measured biases in medicine, which is why funding carries real weight in the score rather than sitting in a footnote.
Is st-johns-wort, hypericum perforatum, sjw, hypericum, klamath weed, tipton's weed, li 160, ws 5570, stw3-vi, ze 117 FDA approved for this use?
No. Its current status is: Not FDA-evaluated for this use. In the United States St. John's wort is sold as a dietary supplement under DSHEA, which means it reaches the shelf without FDA review of efficacy, safety, or potency and the FDA can act only after a problem emerges. It has never been FDA-approved to treat depression or anything else.
Is this medical advice?
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.