Estradiol / estrogen and supplements: 2 sourced interactions
Estrogen therapy, also sold as Estrace, Vivelle-Dot, Climara and Divigel. Of these, 2 studied in people. Plus 1 food and drink line. Each links its source and the date it was checked.
From the Interaction Map Sources checked Oct 10, 2026
A combination missing here is not on our list; that does not mean it is safe together.
Estradiol / estrogen with supplements
Most serious first. Open a row for the mechanism, the source's words and the date checked.
Educational only. Check with your pharmacist or prescriber before changing anything you take.
Moderate
2BiotinStudiedBiotin can make estradiol blood tests wrong
moderate · Studied in people (PubMed) · evidence C · Lab test interference
Excess biotin interferes with tests that use biotin–streptavidin binding.
To raise with your pharmacist or prescriberTell your prescriber and the lab about biotin before hormone tests, and ask how long to pause it first.
- PMID 32567529 · Moerman A, Acta Clin Belg 2022 · Narrative review
- Checked Oct 10, 2026
St John's wortStudiedSt John's wort speeds up estrogen breakdown
moderate · Studied in people (PubMed) · evidence B · Breakdown by liver enzymes
St John's wort induces CYP3A enzymes, which broke down the pill's ethinyl estradiol and norethindrone faster.
To raise with your pharmacist or prescriberTell your prescriber before starting St John's wort. On the pill, the study authors advise adding a barrier method while taking it.
- PMID 14663455 · Hall SD, Clin Pharmacol Ther 2003 · Pharmacokinetic study (12 women)
- Checked Oct 10, 2026
Estradiol / estrogen with food and drink
Food and drink
1GrapefruitStudiedGrapefruit juice raises estrogen levels from oral estradiol
minor · Studied in people (PubMed) · evidence B · Breakdown by liver enzymes
Grapefruit flavonoids probably slow the breakdown of estrogens by liver enzymes (CYP3A4).
To raise with your pharmacist or prescriberIf you drink grapefruit juice regularly with oral estradiol, mention it to your prescriber.
- PMID 7715468 · Schubert W, Maturitas 1994 · Randomised crossover study (8 women)
- Checked Oct 10, 2026
How these lines are sourced
Three kinds of line
- Studied in people (PubMed): PubMed records that were opened and read, graded A (several controlled studies, or a finding in the dosing guidance), B (at least one controlled human study) or C (case reports, observational data or mechanism only).
- Named by an FDA label or NIH page: quoted word for word from that page. Its severity comes from the source’s wording, not from a study of the pair.
- Predicted from how each works, not established: built from sourced facts about each substance, such as the FDA’s table of enzyme roles. Never rated major.
Interaction MapCheck Estradiol / estrogen with everything else you take, together
Keep reading: Supplements and vitamins
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- St. John's wortSt.
- Interaction MapCheck several medicines and supplements at once, each interaction sourced to PubMed, FDA labels or NIH; a pair we have no source for reads as not on our list, never as safe.