A complete safety, timing, and dosage guide for combining Selenium with Vitamin B9 (Folate, Folic Acid, Methylfolate) — 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 B9 (Folate) and Selenium together — they do not interact at the same pathways, so it is safe to combine them.
Vitamin B9 (Folate) and Selenium together have a neutral interaction: they work in separate metabolic pathways and do not interfere with each other's absorption or activity. You can safely add selenium to a supplement routine that already includes folate, while staying within standard doses.
Folate and selenium have completely separate absorption and metabolic routes. Folate is a water-soluble B vitamin absorbed via carrier proteins in the upper small intestine and converted to active methylfolate for one-carbon metabolism. Selenium is a trace mineral absorbed as organic selenomethionine/selenocysteine or inorganic selenite/selenate, then incorporated into selenoproteins like glutathione peroxidases. Because they do not compete for the same transporters or cofactors, there is no biological reason for them to interfere. Even when taken together, each follows its own pathway without altering the other's absorption or function.
If you need both vitamin B9 and selenium, take them once daily with breakfast or lunch. Water-soluble folate can be taken on an empty stomach, but taking it with food reduces any chance of nausea. Selenium is also well absorbed with food, and a meal that includes a source of protein and healthy fat helps. If you miss a dose, take it as soon as you remember, unless it is almost time for your next dose. There is no need to separate these two supplements because they do not compete for absorption.
The form of folate matters for people with certain genetic variants: folic acid needs conversion by the enzyme MTHFR, while methylfolate is already active, but this does not change how selenium is handled. Selenium form also does not affect the interaction — organic selenium (such as selenomethionine) is generally better absorbed than inorganic forms, but neither form impacts folate processing.
This pair commonly appears in prenatal multivitamins and general antioxidant multivitamin formulas. You will also find folate and selenium together in some B-complex blends, though selenium is more often added to immunity or antioxidant support stacks.
Yes, you can take them at the same time. There is no competition between them, so they work independently in your body. I tell my clients it is fine to combine them in one pill or with a meal.
Yes, it is safe to take them daily as long as you stay within recommended doses. Most multivitamins include both, and no adverse interactions are known, so you can continue as part of your routine.
You do not need to wait at all. I typically say just take them together with a meal, so there is no need to count minutes or hours between them.
No, they do not compete. Folate is absorbed by intestinal carrier proteins, while selenium uses different transport mechanisms, so they will not crowd each other out in your gut.
Most healthy adults can take them together. If you have thyroid disease, are on methotrexate, or have kidney problems, check with your doctor first so your selenium intake stays in a safe range and your folate does not interfere with medications.
I recommend taking them with a meal. Food helps smooth out any mild stomach sensitivity, and neither supplement requires an empty stomach for proper absorption.
Reviewed by Caroline M. on April 25, 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.