A complete safety, timing, and dosage guide for combining Evening Primrose Oil (GLA) with Vitamin B2 (Riboflavin) — including how the two supplements interact, the best time of day to take each, and which populations should be careful.
Yes, you can take vitamin B2 (riboflavin) and evening primrose oil (GLA) together — they do not interact and are safe to combine in most cases.
Vitamin B2 (riboflavin) and evening primrose oil (GLA) together are neutral, meaning they do not interfere with each other’s absorption or effects. This combination is safe for most adults and does not require special timing or dosing adjustments.
Riboflavin is a water-soluble B vitamin that is absorbed in the upper small intestine via a carrier-mediated transporter and converted to FAD and FMN, coenzymes involved in energy production and antioxidant function. Evening primrose oil contains GLA, a fat-soluble omega-6 fatty acid that is absorbed with dietary fat, packaged into chylomicrons, and transported through the lymphatic system. These two molecules do not share absorption transporters, metabolic enzymes, or receptor sites, so they do not compete with each other. Riboflavin participates in redox reactions, while GLA is metabolized by elongase and desaturase enzymes that depend on vitamin B6, zinc, and magnesium — but not riboflavin. Thus, there is no recognized biological pathway for a meaningful interaction, and taking them together is pharmacologically quiet.
For most people, the simplest approach is to take both supplements at breakfast or lunch: swallow your riboflavin with a glass of water, and take the evening primrose oil capsule at the same time so the dietary fat in the meal helps GLA absorption. No special spacing between them is needed, and they can be taken together in a single mouthful. If you miss a dose, skip it and take your next scheduled dose rather than stacking two doses. Use reputable brands that follow Good Manufacturing Practices, and consult your pharmacist before starting EPO if you take any prescription medications, especially anticoagulants or anticonvulsants.
Riboflavin is available as free riboflavin or riboflavin-5’-phosphate (the active coenzyme form), and while the latter is slightly more water-soluble, both are well absorbed with food. Evening primrose oil is typically standardized to 8–10% GLA; choose a product that lists the GLA content on the label to know your dose. Neither form requires special timing relative to the other, but a high-quality EPO supplement often includes vitamin E to prevent oxidation of the oil.
This pair is commonly found together in women’s multivitamins and skin-health formulas, often alongside vitamin E and borage oil.
Yes, you can take them at the same time. They don’t compete for absorption, and taking them with a meal makes it easy to remember both.
Yes, it is safe for most healthy adults to take both every day at recommended doses. B2 is water-soluble and extra amounts are excreted in urine, while EPO is well tolerated at typical doses of 1–3 grams daily.
You don’t need to wait at all — take them together with a meal. There is no timing interaction that requires you to space them out.
No, they don’t compete for absorption. B2 is water-soluble and absorbed in the upper small intestine, while EPO’s GLA is fat-soluble and absorbed into the lymphatic system after emulsification — so their absorption pathways don’t overlap.
Most people are fine, but you should avoid EPO if you are pregnant unless your doctor approves it, and you must ask your doctor first if you take anticonvulsants or blood thinners. Vitamin B2 is safe for nearly everyone, even at higher doses.
Take them with food. B2 is absorbed fine either way, but evening primrose oil is a fat-soluble oil that needs dietary fat to be absorbed well, so a meal with some fat is the better choice for both.
Reviewed by Caroline M. on April 15, 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.