A complete safety, timing, and dosage guide for combining Inositol (PCOS/mood) 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, you can safely take St. John's Wort and inositol together — these two supplements have no significant interaction and can be combined.
St. John's Wort and inositol together are safe to combine. St. John's Wort does not affect how your body processes inositol, and inositol does not influence St. John's Wort metabolism. You can take them concurrently without adjusting doses.
St. John's Wort is a well-known inducer of cytochrome P450 enzymes, particularly CYP3A4 and CYP2C19, which speeds up the breakdown of many medications and supplements. Inositol, by contrast, is a naturally occurring sugar alcohol that acts as a second messenger in insulin signaling and as a precursor for phosphatidylinositol phosphates in brain cells. It is not metabolized by these same liver enzymes and does not induce or inhibit CYP450 activity. Because their metabolic pathways are entirely distinct, there is no competition for absorption, transport proteins, or receptor sites. Inositol is absorbed via sodium-dependent glucose transporters, while St. John's Wort constituents are lipophilic and absorbed via passive diffusion — another reason they do not interfere with each other.
To take St. John's Wort and inositol together safely, simply take them as directed on their labels — no special timing or spacing is needed. The only 'best practice' is to be consistent: take both at the same time each day, preferably with a meal if your stomach is sensitive. If you are using inositol for PCOS, the typical dose is 2–4 g of myo-inositol plus 50–100 mg of D-chiro-inositol daily. For St. John's Wort, the common dose is 300 mg three times daily or 900 mg once daily, standardized to 0.3% hypericin. If you miss a dose, skip it and resume your normal schedule — do not double up.
The form of St. John's Wort matters for drug interactions: extracts standardized to hyperforin are stronger CYP3A4 inducers, but even low-hyperforin products can have enzyme effects. Inositol is commonly sold as myo-inositol, D-chiro-inositol, or a 40:1 blend typical for PCOS support; these are both water-soluble and equally absorbed. No form-specific interaction has been reported between these two supplements.
Yes, you can take both at the same time of day. There is no known interaction, and they do not compete for absorption. I routinely combine them in my practice for patients who need both mood and PCOS support.
Yes, it is safe to take them daily as long as you are not taking any medications that interact with St. John's Wort. Inositol is well tolerated for long-term use, and St. John's Wort can be used for months with monitoring. Just watch for side effects like nausea or photosensitivity.
You do not need to wait at all. You can take both at the same time, with or without food. If you prefer, you can split them between morning and evening, but it is not necessary.
No, they do not compete. St. John's Wort is fat-soluble and absorbed passively, while inositol is water-soluble and absorbed via glucose transporters. Their absorption routes are completely separate.
If you are on antidepressants, blood thinners, or birth control pills, you should avoid St. John's Wort entirely because of drug interactions. Inositol is safe for most people, so the caveat is really about St. John's Wort, not the combination.
Inositol is fine on an empty stomach, but if you get nausea, take it with food. St. John's Wort is also fine either way. I usually suggest taking both with breakfast to build a habit and reduce GI upset.
Reviewed by Caroline M. on April 16, 2025 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.