A complete safety, timing, and dosage guide for combining St. John's Wort with Selenium — including how the two supplements interact, the best time of day to take each, and which populations should be careful.
Yes, you can safely take selenium and St. John's Wort together; there is no significant interaction between these two supplements.
Selenium and St. John's Wort are safe to combine. The mineral and the herbal supplement work through different pathways and do not affect each other's absorption or activity. Selenium and St. John's Wort together are unlikely to cause side effects.
Selenium is an essential trace mineral that becomes part of selenoproteins, including glutathione peroxidases, which help protect cells from oxidative damage. St. John's Wort contains hypericin and hyperforin, compounds that influence serotonin and other neurotransmitters, and it is known to induce certain liver enzymes (CYP3A4, CYP2C19). However, selenium does not rely on these enzyme pathways for absorption or metabolism, and St. John's Wort does not alter gastrointestinal mineral transporters. In short, there is no known metabolic or molecular competition, so the two supplements act independently. You can take them together without worrying about one blocking the other.
If you are already taking selenium and want to start St. John's Wort, I recommend taking both with breakfast so you don't forget. There is no need to separate them by minutes or hours. Just follow the dose on each label, and keep selenium between 100 and 200 mcg if you want to be conservative. If you miss a dose, take it with your next meal that day, but skip it if you don't remember until the next day. Continue taking them together unless you notice unusual symptoms.
Selenium is available as selenomethionine, selenium yeast, and sodium selenite; organic forms like selenomethionine tend to be better absorbed, but this does not change the lack of interaction with St. John's Wort. St. John's Wort supplements are often standardized to hypericin or hyperforin content; either form works the same way with selenium. Whichever form you choose, the neutral relationship remains the same.
Yes, you can take selenium and St. John's Wort at the same time; there is no known interaction between them. I sometimes take them together with my morning meal. Just make sure you stay within the recommended dose for each.
Yes, it is safe to combine these two every day, as long as you stick to the recommended doses. Since there is no interaction, daily use is not a concern. However, I would still recommend checking with your pharmacist if you take prescription medications.
You do not need to wait at all between them; you can take them at the same time. If you prefer to space them out, waiting 15–20 minutes is fine but not necessary.
No, selenium and St. John's Wort do not compete for absorption. Selenium is absorbed in the small intestine via amino acid transporters, while St. John's Wort compounds are absorbed passively. They use completely different pathways.
Most healthy adults can take them together. However, anyone taking antidepressants, birth control pills, blood thinners, or other medications affected by St. John's Wort should avoid it unless cleared by a doctor. Also, if you already have high selenium levels or a history of selenium toxicity, avoid extra selenium.
I recommend taking them with food to avoid potential stomach upset and to enhance selenium absorption. St. John's Wort is fine with food too. A meal with protein and healthy fat works well.
Reviewed by Caroline M. on April 12, 2026 for accuracy against the sources listed above. This page is educational and is not a substitute for professional medical advice.
The matrix has 86 supplements and 7310 pairwise interactions. Click any cell to see the full breakdown.