A complete safety, timing, and dosage guide for combining St. John's Wort with Iron (Ferrous Sulfate, Ferrous Bisglycinate) — including how the two supplements interact, the best time of day to take each, and which populations should be careful.
Yes, you can take Iron (Ferrous Sulfate, Ferrous Bisglycinate) with St. John's Wort safely because they do not significantly interact.
Iron (Ferrous Sulfate, Ferrous Bisglycinate) and St. John's Wort together are neutral, with no significant interaction. They work through entirely different absorption and metabolic pathways. Taking them as directed is generally safe.
Iron is absorbed mainly in the duodenum and proximal jejunum through the divalent metal transporter DMT1, and its uptake depends on gastric acid and dietary enhancers like vitamin C. St. John's Wort, by contrast, contains hyperforin, which strongly induces cytochrome P450 enzymes (CYP3A4, CYP1A2) and the efflux transporter P-glycoprotein in the gut and liver. These induction effects accelerate the breakdown of many medications, but iron does not undergo CYP-mediated metabolism or rely on P-glycoprotein for absorption. St. John's Wort does not contain significant amounts of iron-binding polyphenols or tannins that would chelate ferrous iron. Therefore, there is no shared absorption pathway, enzyme system, or carrier protein that would cause a meaningful interaction.
If you need both supplements, the simplest approach is to take them at different times of day. For example, take your iron on an empty stomach in the morning with a glass of orange juice, and take St. John's Wort later with lunch to minimize any gastrointestinal discomfort. Since there is no direct interaction, spacing them out is mainly for your comfort and to allow iron to be absorbed without food. If you miss a dose of either, just take it when you remember, unless it is almost time for the next dose. If St. John's Wort causes any nausea, taking it with food is fine and will not interfere with iron absorption.
Ferrous sulfate is a crystalline iron salt that requires an acidic gastric environment for optimal dissolution and absorption; ferrous bisglycinate is a chelated form in which iron is bound to two glycine molecules, making it more stable and less dependent on stomach acid, with fewer gastrointestinal side effects. Neither form is metabolized by CYP enzymes, and St. John's Wort does not alter the absorption of either form. If you experience nausea with ferrous sulfate, switching to ferrous bisglycinate may help, but you can take it alongside St. John's Wort without concern.
Yes, you can take them at the same time because there is no known interaction between these two supplements. Iron is absorbed via DMT1 and does not use the liver enzymes that St. John's Wort induces. To be extra cautious, you can separate them by a few hours, but it is not required.
Yes, it is safe to combine iron and St. John's Wort every day if your healthcare provider has recommended both. Their mechanisms are completely different, so taking them long-term together is not a concern. Just monitor for standard St. John's Wort side effects like sun sensitivity and possible drug interactions.
You don't need to wait between iron and St. John's Wort specifically, but if you enjoy taking St. John's Wort with food, simply take iron at a separate meal or time to avoid any absorption interference from food. Some people prefer to take iron 30–60 minutes before breakfast and St. John's Wort with lunch or dinner.
No, iron and St. John's Wort do not compete for absorption. Iron uses a divalent metal transporter and St. John's Wort's constituents are lipophilic compounds that absorb passively; their absorption pathways are entirely distinct.
People with iron overload conditions like hemochromatosis should avoid iron and therefore should not take this combination. Anyone taking medications that interact with St. John's Wort—such as SSRIs, oral contraceptives, or warfarin—should also avoid St. John's Wort, though iron itself is still fine. Pregnant or nursing women should use St. John's Wort only after consulting their healthcare provider.
Take iron on an empty stomach if you can, ideally with vitamin C to boost absorption; if it upsets your stomach, take it with a small meal. St. John's Wort can be taken with food to reduce possible nausea, and it is not affected by iron. If you take both together, a light meal is fine.
Reviewed by Caroline M. on June 14, 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.