Seal oil is a dietary supplement made from the fat of seals, primarily harp seals harvested in Atlantic Canada. Like fish oil, it provides omega-3 fatty acids, but its chemical structure and fatty acid profile differ in ways that may affect how your body processes it. It occupies a niche space in the supplement world, partly because it contains meaningful amounts of a lesser-known omega-3 called DPA, and partly because legal restrictions limit where it can be sold.
Fatty Acid Profile and How It Differs From Fish Oil
Seal oil contains the same two omega-3 fatty acids found in fish oil: EPA (about 9% of total fatty acids) and DHA (about 11.7%). Where it stands apart is its DPA content, which sits around 5.2%. Most commercial fish oils contain less than 2% DPA by weight, making seal oil one of the richest natural sources of this particular omega-3. Even menhaden oil, the richest fish-based DPA source, tops out at roughly 4.9%.
DPA has drawn increasing scientific attention. A human supplementation trial using high-purity DPA found that participants’ blood levels of EPA, DPA, and DHA all increased after taking it. Researchers observed that DPA was converted backward into EPA and forward into DHA, suggesting it acts as a kind of storage pool that the body draws from as needed. Cell and animal studies link DPA to reduced platelet clumping, improved fat metabolism, better blood vessel repair, and resolution of chronic inflammation. It may also support neural health, though human data on that front is still limited.
The Triglyceride Structure Difference
Beyond the fatty acid percentages, seal oil and fish oil differ at a molecular level. Fats are built on a three-armed backbone called glycerol, and where the omega-3s attach to that backbone matters. In fish oil, EPA and DHA sit mostly in the middle position (called sn-2). In seal oil, they’re attached primarily to the outer positions (sn-1 and sn-3). This isn’t just a chemistry detail. When rats were fed seal oil and fish oil, the structural pattern of the original oil carried through into their lymph, the system that absorbs dietary fat. Seal oil was more effective at reducing triglyceride levels in both plasma and liver compared to fish oil in that study, suggesting the positional difference changes how the body handles these fats.
Whether this translates cleanly to humans is less certain. A controlled trial in healthy men taking seal oil supplements found no significant changes in total cholesterol, LDL, HDL, triglycerides, blood pressure, heart rate, or platelet aggregation. That’s a notable gap between the animal data and the human evidence available so far.
Where Seal Oil Comes From
Nearly all commercial seal oil is produced in Atlantic Canada, sourced from harp seals during the annual harvest. The Northwest Atlantic harp seal population was estimated at 4.4 million animals in 2024, though that represents a decline from 5.6 million in 2019, dropping at roughly 4.7% per year. Pup production in 2022 hit its lowest point since 1994, at about 614,100.
Fisheries and Oceans Canada sets harvest quotas designed to give the population an 80% probability of recovering over the next 30 years. For the 2025 to 2029 period, sustainable annual harvest levels range from 113,000 to 253,000 seals depending on the age composition of the catch. These quotas are recalculated as population surveys update, and the recent downward trend has tightened allowable harvests.
Legal Restrictions on Sale
Seal oil is legal to buy and sell in Canada, but the picture changes sharply across borders. In the United States, the Marine Mammal Protection Act makes it illegal to transport or sell any marine mammal product, including harp seal oil, except for narrow purposes like scientific research or public display. This isn’t a theoretical concern. In 2023, a Canadian company called FeelGood Natural Health Stores pleaded guilty to violating the Lacey Act for knowingly selling harp seal oil capsules into the U.S. market.
The European Union also bans most commercial trade in seal products, with limited exceptions for products from Indigenous hunts. If you’re outside Canada, purchasing seal oil supplements online may put you on the wrong side of import laws even if the seller ships willingly.
Side Effects and Interactions
No large-scale safety studies focus specifically on seal oil, but because its active components overlap heavily with fish oil, the same general cautions apply. Common side effects of omega-3 supplements include fishy aftertaste, bad breath, heartburn, nausea, and diarrhea. High doses can increase bleeding risk.
The interaction list matters most if you take other medications. Omega-3 supplements can amplify the effects of blood thinners, potentially raising the chance of bleeding. They may also strengthen the effect of blood pressure medications, reduce vitamin E levels over time, and interact with the weight-loss drug orlistat, which can block absorption of the fatty acids. Certain hormonal contraceptives may also blunt the triglyceride-lowering effects that omega-3s typically provide.
Who Actually Uses It
Seal oil has deep roots in Indigenous Arctic diets. The Greenland Inuit traditionally consumed seal and whale alongside fish as staple foods, and early research into the cardiovascular benefits of omega-3s drew heavily on observations of these populations. Today, seal oil supplements are marketed primarily in Canada, often positioned as a premium alternative to fish oil because of the higher DPA content and the triglyceride structure difference.
For most people outside Canada, fish oil or algae-based omega-3 supplements remain the practical choice, both for legal reasons and because the human clinical evidence for seal oil’s superiority over fish oil is still thin. The DPA angle is genuinely interesting, and concentrated DPA products from non-seal sources are starting to appear on the market for those specifically seeking that fatty acid. But if you’re in a country where seal products are legal and you want a natural source of all three major omega-3s in a single supplement, seal oil delivers that in a way few alternatives match.