Fish oil vs algae oil is mostly a question of diet, EPA and label amounts. Both supply the long-chain omega-3s EPA and DHA. Fish oil comes from oily fish such as anchovies and usually provides both EPA and DHA. Algae oil comes from microalgae, the original source of the omega-3s in fish, and is plant-based, but it is usually richer in DHA than EPA. If you avoid fish or eat a vegan diet, algae oil is the natural choice. If you eat fish and want both fats in one softgel, fish oil is the established option. Here is the comparison.
Key takeaways
- The EPA and DHA in fish are first made by microalgae and build up in fish through the food chain.
- Algae oil supplements usually provide around 100 to 300 mg of DHA, and only some contain EPA.
- A small study found DHA from algal oil capsules was as available to the body as DHA from cooked salmon.
- Pure Omega+™ is fish oil from anchovy in a gelatin softgel, so it is not suitable for a plant-based diet.
Where do the omega-3s in fish oil and algae oil come from?
It surprises many people that fish do not make EPA and DHA on their own. The EPA and DHA in fish are first made by microalgae and build up in fish through the food chain. Small fish eat algae and plankton, larger fish eat the small fish, and the omega-3s concentrate along the way. The NIH Office of Dietary Supplements describes exactly this path.
That gives two routes to the same fats:
- Fish oil is pressed and refined from oily fish. Small, fast-growing species such as anchovies and sardines are common sources.
- Algae oil is extracted from microalgae grown in controlled tanks, skipping the fish entirely.
Krill oil and cod liver oil are other marine options, and plant oils like flaxseed supply ALA, a shorter omega-3 that the body converts to EPA and DHA only in small amounts. For how EPA and DHA themselves differ, see our explainer on EPA vs. DHA.
Fish oil vs algae oil: side by side
| Fish oil | Algae oil | |
|---|---|---|
| Source | Oily fish such as anchovy and sardine | Microalgae grown in tanks |
| EPA | Usually present, often the larger share | Present in some products only |
| DHA | Usually present | The main omega-3 in most products |
| Plant-based diets | Not suitable | Suitable if the capsule is plant-based too |
| Fish allergen | Yes, listed on the label | No fish, though always check the label |
| Typical cost | Generally lower per gram of omega-3 | Generally higher |
As a reference point, the Office of Dietary Supplements describes a typical fish oil supplement as about 1,000 mg of fish oil providing 180 mg of EPA and 120 mg of DHA, though amounts vary widely. Algae oil supplements usually provide around 100 to 300 mg of DHA, and only some contain EPA. Higher-potency products of either kind exist, which is why the label numbers matter more than the category.
Is algae oil as good as fish oil for DHA?
For DHA, the research is reassuring. A small study found DHA from algal oil capsules was as available to the body as DHA from cooked salmon. In that 2008 trial, 32 healthy adults took 600 mg of DHA a day for two weeks, either from algal oil capsules or from portions of cooked salmon. DHA levels in the blood and in red blood cells rose by similar amounts in both groups.
The study was short and small, and it looked only at DHA. It does not tell us about EPA, because most algae oils supply little or none of it. According to the Office of Dietary Supplements, algae oils typically contain their omega-3s in the triglyceride form, the same form that occurs naturally in fish oil.
Which omega-3 source fits your diet?
If you eat a vegan or vegetarian diet
Algae oil is the direct plant-based source of DHA, and some products add EPA. Check that the capsule itself is plant-based, since some algae oils still come in gelatin softgels.
If you have a fish allergy
Fish oil is made from fish, and fish is one of the major food allergens that must be declared on the label. Algae oil avoids fish as an ingredient. Anyone with a food allergy should read the full label and check with their healthcare provider before choosing either.
If you already eat fish
Fish oil is the more familiar and usually less expensive way to get both EPA and DHA in one product. It has the longer research history, since most omega-3 trials have used fish oil.
If purity and sustainability are on your mind
The Office of Dietary Supplements notes that although some fish contain mercury, omega-3 supplements have not been found to contain it, because it is removed during processing and purification. Algae grown in tanks avoids ocean contaminants by design. On sustainability, small forage fish such as anchovy and tank-grown algae are both common choices; look for clear sourcing information on whichever you buy.
Freshness matters for both
EPA and DHA are delicate fats that can oxidize, whatever their source. Studies of store-bought products have found real problems. A 2015 New Zealand study reported that most fish oil products tested contained less EPA and DHA than their labels claimed and that many exceeded recommended oxidation levels; it also found that price and country of origin were poor guides to quality. A 2015 study of 171 omega-3 products sold in Canada found that half exceeded voluntary oxidation limits.
Those findings are the case for independent, batch-by-batch testing, and for storing any omega-3 in a cool, dry place. Our guide to choosing a fish oil supplement covers the freshness checks in detail.
Where Pure Omega+ fits
To be clear about our own product: Pure Omega+ is fish oil, not algae oil. The label lists 2,400 mg of fish oil per two-softgel serving, providing 1,440 mg of omega-3 with 864 mg of EPA and 576 mg of DHA. Pure Omega+™ is fish oil from anchovy in a gelatin softgel, so it is not suitable for a plant-based diet. It contains fish (anchovy), and the softgel may contain porcine. If you follow a vegan diet or avoid fish, an algae oil is the category to look at instead.
For people who do eat fish, Pure Omega+ provides both EPA and DHA in one lemon-flavored softgel. The suggested use is two softgels daily with meals, a 30-day supply per bottle. It is formulated to contribute to a healthy heart, support joint flexibility, promote brain and nerve function, support vision health and aid in memory care.* Every batch is third-party tested for purity and potency, and it is bottled in an NSF-certified, GMP-certified, FDA-registered U.S. facility; details are on our standards page.
Safety notes
The Pure Omega+ label states: Do not exceed recommended dose. Pregnant or nursing mothers, children under the age of 18, and individuals with a known medical condition should consult a physician before using this or any dietary supplement.
Whatever the source, omega-3s can have antiplatelet effects at high doses, so talk with your healthcare provider first if you take a blood thinner such as warfarin. Side effects are usually mild, such as an unpleasant taste, heartburn or an upset stomach.
Frequently asked questions about fish oil vs algae oil
Is algae oil better than fish oil?
Not across the board. Algae oil suits vegan diets and people avoiding fish, and its DHA appears well absorbed. Fish oil usually supplies more EPA and costs less. The better choice depends on your diet and the EPA and DHA amounts on the label.
Does algae oil contain EPA?
Some algae oils do and many do not. Most are DHA-focused. Check the Supplement Facts panel for a separate EPA line in milligrams.
Is algae oil vegan?
The oil itself is plant-based. Whether the product is vegan depends on the capsule, so look for a plant-based softgel or a vegan statement on the label.
Can I take fish oil if I am allergic to fish?
Fish oil is made from fish and carries a fish allergen statement. If you have a fish allergy, talk with your healthcare provider before taking it; algae oil avoids fish as an ingredient.
Which has more omega-3 per capsule?
It depends on the product, not the source. Typical algae oils provide around 100 to 300 mg of DHA, and fish oil concentrates range widely. Compare the EPA and DHA lines per serving.
Related reading from our Wellness Hub
- EPA vs. DHA: How the Two Omega-3s Differ and Why Labels List Both
- How Much Omega-3 Per Day? EPA and DHA Amounts Explained
- Fish Oil Burps? How to Take Pure Omega+ Comfortably
Sources
- NIH Office of Dietary Supplements: Omega-3 Fatty Acids, Fact Sheet for Health Professionals (sources, algal oil, forms, mercury, safety)
- Arterburn LM, et al. Algal-oil capsules and cooked salmon: nutritionally equivalent sources of docosahexaenoic acid. J Am Diet Assoc, 2008
- Albert BB, et al. Fish oil supplements in New Zealand are highly oxidised and do not meet label content of n-3 PUFA. Sci Rep, 2015
- Jackowski SA, et al. Oxidation levels of North American over-the-counter n-3 (omega-3) supplements. J Nutr Sci, 2015
Individual results vary.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
