A complete safety, timing, and dosage guide for combining Selenium with Krill Oil — including how the two supplements interact, the best time of day to take each, and which populations should be careful.
Yes, you can take selenium and krill oil together safely—there is no clinically meaningful interaction between these two supplements.
Selenium and Krill Oil together are considered safe and neutral. Selenium works in the aqueous phase as part of antioxidant enzymes, while krill oil provides lipid-phase omega-3s and astaxanthin. They do not compete for absorption or conversion pathways, so you can take them without special timing.
Selenium is a trace mineral that becomes part of selenoproteins, including glutathione peroxidases, which neutralize water-soluble peroxides and support thyroid hormone metabolism. Krill oil delivers EPA and DHA as phospholipids, along with astaxanthin, a fat-soluble carotenoid antioxidant. These antioxidants operate in different cellular compartments—selenium in the cytosol and extracellular space, krill oil components in cell membranes and lipid environments. There is no shared transporter, receptor, or enzyme system that would cause competition. Krill oil may increase overall dietary fat intake, but fat does not impair selenium absorption; in fact, selenium absorption is not fat-dependent. Therefore, the combination is pharmacologically neutral and safe.
For most people, the simplest approach is to take selenium and krill oil together with your largest meal, such as lunch or dinner, when your stomach acid and digestive enzymes are most active. Selenium does not need any special companion food, but krill oil absorbs best with dietary fat, so a meal containing avocado, olive oil, or fish is ideal. There is no required waiting time between the two—you can take them in the same multiserving or supplement organizer. If you miss a dose, just take it at your next meal; do not double up. For sustained antioxidant support, keep your selenium intake consistent daily rather than in periodic high doses, and choose a krill oil product that lists its astaxanthin content to support the lipid-phase antioxidant benefit.
Selenium is available as selenomethionine, selenium-enriched yeast, selenocysteine, and sodium selenite; selenomethionine tends to be absorbed more efficiently than inorganic forms, but this does not alter its interaction with krill oil. Krill oil is naturally in phospholipid form, which differs from fish oil's triglyceride and ethyl ester forms, but again, this is unrelated to selenium. If you have a choice, choose a selenium form you already tolerate well; the specific form will not change the safety of combining it with krill oil.
Selenium and krill oil are not a classic fixed combination, but they occasionally appear together in comprehensive antioxidant formulas or cardiovascular health stacks alongside vitamin E, coenzyme Q10, and additional omega-3s. Some multis available on the market include both selenium and small amounts of omega-3s, though krill oil is more often added separately by users who want a phospholipid-based omega-3.
Yes, you can take them at the same time. I do not see any mechanism by which they compete for absorption or affect each other's metabolism. I take both with breakfast when I have a meal with some fat.
It is safe for most people to combine them daily at standard doses. I would just be careful with total selenium intake from all sources, keeping it under 200 mcg unless you are under medical supervision. Daily krill oil within the recommended serving is fine.
You do not need to wait at all. I would actually recommend taking them together with a meal for convenience and to support krill oil absorption with dietary fat.
No, they do not compete. Selenium is absorbed as a mineral in the small intestine and krill oil is digested as a fat by lipases and bile. There are no shared transporters or receptors that would cause a conflict.
I would tell people on blood thinners, those with a krill or seafood allergy, and anyone with existing thyroid disease to check with their healthcare provider first. Pregnant women should also avoid extra selenium supplementation beyond prenatal levels, but the combination is not inherently dangerous for healthy adults.
I would take them with food, especially a meal that contains some fat. Selenium is fine on an empty stomach but taking it with food reduces nausea; krill oil is better absorbed with fat and less likely to cause fishy burps when taken with a meal.
Reviewed by Caroline M. on April 27, 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.