A complete safety, timing, and dosage guide for combining Evening Primrose Oil (GLA) 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 take St. John's Wort and Evening Primrose Oil together — there is no significant interaction and the combination is safe.
St. John's Wort and Evening Primrose Oil together are safe — they work through distinct metabolic pathways and do not interfere with each other's absorption or activity. No clinically significant interaction has been reported.
St. John's Wort is a well-known inducer of cytochrome P450 enzymes, especially CYP3A4, which accelerates the metabolism of many drugs. Evening Primrose Oil delivers gamma-linolenic acid (GLA), an omega-6 fatty acid that is converted to dihomo-gamma-linolenic acid (DGLA) and then to anti-inflammatory prostaglandins. These two pathways are completely separate — GLA does not rely on CYP3A4 or other cytochrome P450 enzymes for its metabolism, and St. John's Wort does not alter the desaturase enzymes that process GLA. Because neither supplement affects the other's absorption, distribution, or elimination, they can be taken together without any known negative interaction.
For best results, take both supplements together with breakfast if that meal contains some fat, such as eggs or yogurt with nuts. If you prefer to separate them, take St. John's Wort in the morning and Evening Primrose Oil at dinner. St. John's Wort should be taken at the same time each day to maintain steady levels. If you miss a dose, skip it and resume your regular schedule — do not double up. Always review your full medication list with your healthcare provider before starting this pair, since St. John's Wort can alter drug levels.
Not commonly found in commercial blends, but some mood-support routines pair St. John's Wort with omega-3s and SAMe, and Evening Primrose Oil is sometimes added for hormonal mood symptoms.
Yes, you can take them at the same time. They do not compete for absorption and no interaction has been reported. I would just take them with food if you have a sensitive stomach.
Yes, it is safe to take them together daily at recommended doses. I have seen no evidence that long-term use of this combination causes problems. You should still be careful about St. John's Wort's interactions with other medications.
There is no need to wait between these two supplements. You can take them at the same time or spaced apart however you prefer, since neither affects the other's absorption.
No, they do not compete for absorption. St. John's Wort is absorbed in the upper gastrointestinal tract, while Evening Primrose Oil is digested as a fat and absorbed through the lymphatic system — different routes entirely.
People who are pregnant or breastfeeding should avoid St. John's Wort, and anyone on antidepressants, blood thinners, or birth control pills should talk to their doctor first. Evening Primrose Oil should be used with caution in people with epilepsy or bleeding disorders.
You can take St. John's Wort on an empty stomach, but food may reduce mild stomach upset. Evening Primrose Oil is best taken with meals containing some fat to enhance GLA absorption, so together with food is the simplest approach.
Reviewed by Caroline M. on April 8, 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.