A complete safety, timing, and dosage guide for combining Cod Liver Oil with Vitamin B7 (Biotin) — 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 B7 (Biotin) and Cod Liver Oil together; no significant interaction exists between these two supplements, so they are safe to combine.
Vitamin B7 (Biotin) and Cod Liver Oil together are considered safe because they are absorbed and processed by completely different pathways. Biotin is a water-soluble B-vitamin used in energy metabolism, while cod liver oil is a fat-based source of omega-3s plus vitamins A and D. Taking them together does not reduce the effectiveness of either supplement.
Biotin is water-soluble and is absorbed in the proximal small intestine by the sodium-dependent multivitamin transporter (SMVT), the same transporter that handles pantothenic acid and lipoic acid. Cod liver oil, by contrast, is a mixture of triglycerides containing omega-3 fatty acids (EPA and DHA) along with fat-soluble vitamins A and D, which are absorbed into enterocytes and packaged into chylomicrons that travel through the lymphatic system. Because these two absorption pathways do not share any transporter, receptor, or carrier protein, there is no competition at the intestinal level. Biotin also acts as a cofactor for carboxylase enzymes in the cytoplasm and mitochondria, while the vitamin A and vitamin D from cod liver oil signal through nuclear receptors — these are entirely different mechanistic domains. There is no known cytochrome P450-mediated interaction that would alter biotin metabolism or accelerate the breakdown of either supplement.
There are no special timing rules for this pair, so the best practice is simplicity: take both once daily with a main meal such as breakfast or lunch. A meal containing some fat is ideal for the fat-soluble vitamins in cod liver oil, while biotin can be taken on an empty stomach if you prefer — but together is perfectly fine. If you miss a biotin dose, just take it when you remember, but if it is almost time for your next dose, skip the missed one. For cod liver oil, if you miss a day, simply take the next dose with your next meal and do not double it. In addition, keep an eye on your total vitamin A from all sources (cod liver oil, multivitamins, liver) so you stay below the tolerable upper limit for preformed vitamin A.
Biotin is almost always sold as free d-biotin, which is well absorbed from tablets, capsules, and gummies, and this form does not interact with cod liver oil regardless of the delivery format. Cod liver oil can be liquid or encapsulated; both are fine, though liquid forms may go rancid faster once opened. The main form-related concern is the high concentration of preformed vitamin A in cod liver oil compared with regular fish body oil, so keep your total daily vitamin A intake in mind if you also take a multivitamin or eat liver regularly.
Biotin + cod liver oil is not a standard commercial stack, but it shows up in DIY hair, skin, and nail routines where biotin is paired with an omega-3/vitamin D source like cod liver oil for overall wellness. You will also see biotin combined with regular fish oil in some beauty supplements, but cod liver oil specifically is less common in those formulas.
Yes, you can take them at the same time. They are absorbed through different mechanisms, and I have no clinical concern that one would block the other. Taking them together with a meal is the simplest way to stay consistent.
Yes, it is safe for most people to take both daily. The only thing to watch is the vitamin A content in cod liver oil, so keep your total daily vitamin A below the upper limit. If you are pregnant, discuss it with your obstetrician first.
You do not need to wait at all. There is no absorption competition or interaction, so spacing them out is unnecessary. Taking them together, or at separate times of day, will not change how well they work.
No, they do not compete. Biotin is absorbed through a specific water-soluble vitamin transporter, while the fats and fat-soluble vitamins in cod liver oil are absorbed into the lymphatic system after forming chylomicrons. Different pathways means no competition.
Most healthy adults can take them without issue. Pregnant people should avoid high vitamin A doses from cod liver oil, and anyone on blood thinners should get medical clearance first. If you have chronic liver or kidney disease, ask your doctor before starting cod liver oil.
Take cod liver oil with a meal that contains at least some fat to improve absorption of its fat-soluble vitamins and reduce burping. Biotin can be taken with or without food, so taking both at breakfast is an easy and effective approach.
Reviewed by Caroline M. on July 23, 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.