A complete safety, timing, and dosage guide for combining Magnesium (Citrate, Glycinate, Oxide, Threonate) with St. John's Wort — including how the two supplements interact, the best time of day to take each, and which populations should be careful.
Yes, magnesium (citrate, glycinate, oxide, threonate) and St. John's Wort are safe to take together. There is no known interaction between them.
Magnesium (citrate, glycinate, oxide, threonate) and St. John's Wort together are safe for most adults. St. John's Wort does not affect magnesium absorption or mineral balance, and magnesium does not alter St. John's Wort's usual effects.
St. John's Wort is a well-known inducer of drug-metabolizing enzymes in the liver, especially cytochrome P450 3A4 and P-glycoprotein efflux pumps. Magnesium, however, is an electrolyte mineral absorbed via both passive and active pathways in the small intestine and is not metabolized by these enzymes. Magnesium does not rely on CYP450 breakdown for elimination, so enzyme induction does not impact its safety or effectiveness. Likewise, magnesium does not alter serotonin reuptake activity or the monoamine-oxidative pathways linked to St. John's Wort's mechanism of action. The two operate through independent physiological routes, which is why no clinically relevant interaction is expected.
If you want to take both daily, take St. John's Wort in the morning with breakfast—fat in breakfast can improve absorption, though this is not essential—and take magnesium in the evening, either with dinner or near bedtime. There is no required spacing between them, but if you find the combination causes GI upset, separate the doses by 2 hours. Choose a well-absorbed magnesium form like citrate or glycinate, especially if you take St. John's Wort long-term. If you miss a dose of St. John's Wort, skip it and continue the next day; never double up. Always inform your pharmacist or doctor that you take St. John's Wort, since it interacts with many medications, even though it does not interact with magnesium.
The magnesium salt matters for absorption and gastrointestinal tolerance, but all forms—citrate, glycinate, oxide, and threonate—are safe to take with St. John's Wort. St. John's Wort is typically standardized to hypericin or hyperforin; hyperforin-deficit extracts may have weaker enzyme-inducing effects, but that only impacts medications, not magnesium. If magnesium oxide causes loose stools, switching to glycinate or citrate may be more comfortable, but that is a form choice unrelated to St. John's Wort.
Yes, you can take them at the same time if you have no other medications that St. John's Wort would interfere with. I don't see any absorption or metabolism conflict between the two. If your stomach is sensitive, taking them at separate meals can help.
Yes, it is safe to combine them daily for most adults. St. John's Wort will not deplete magnesium, and magnesium will not reduce St. John's Wort's effects. Still, I would check with your doctor about St. John's Wort itself if you take any prescription medication.
There is no required wait time between these two. If you take other medications, I would wait at least 2 hours between St. John's Wort and that medication, but magnesium can be taken at any point.
No, I don't see any competition for absorption between them. Magnesium uses intestinal mineral transporters, while St. John's Wort relies on passive diffusion and gut metabolism. They are absorbed through separate pathways, so you can take them together without worrying about nutrient interference.
I would not recommend this combination to anyone who is taking medications such as blood thinners, antidepressants, birth control pills, or transplant anti-rejection drugs because St. John's Wort can lower their levels. Pregnant or breastfeeding women and people with kidney disease should also avoid taking both without specific medical supervision. If you fall into these groups, talk to your prescriber before starting.
I recommend taking St. John's Wort with food to reduce nausea and taking magnesium with food to reduce stomach irritation, especially if you use magnesium oxide. Taking both with a meal is fine. If you take magnesium threonate or glycinate, you can take them on an empty stomach if you prefer.
Reviewed by Caroline M. on April 26, 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.