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Visit any pharmacy and you’ll find plenty of fish oil pills that you can use to increase your omega-3 intake. However, there’s another option that may be more suitable for you and your health goals: algae oil.
Algae oil has many of the same nutritional properties that make fish oil such a valuable part of a healthy diet, including rich stores of the omega-3 fatty acids EPA and DHA. In this article, we’ll go over the similarities and differences between fish oil and algae oil in regard to nutrition, sustainability, and purity. We’ll also walk through how you decide which of these supplements is right for your needs.
What Are Algae Oil and Fish Oil?
Algae oil is derived from microalgae, a kind of microscopic aquatic plant organism. Microalgae produce omega-3s via photosynthesis; in other words, they are the primary producers of these valuable fatty acids!
Algae oil is unique as a plant-based omega-3 supplement because it contains the omega-3s docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Other plant-based omega-3 sources contain a different kind of omega-3 altogether called alpha-linolenic acid (ALA). While ALA is helpful in its own right, your body needs to convert ALA into DHA and EPA in order to use it. 
This makes algae oil vastly superior to these plant-based sources. In fact, one study that examined the effects of different plant-based omega-3 sources found that the ALA from nuts and seed oils were not converted to DHA at all once they were metabolized by the participants. Meanwhile, participants who took microalgae oil saw significant increases in their DHA levels.
Fish oil is a popular omega-3 supplement. These supplements usually come in the form of capsules or pills, though some are also distributed in pure liquid form. Fish oil is usually extracted from a variety of fatty fish like salmon, tuna, herring, or mackerel, which get their omega-3 stores from the microalgae they ingest. Fish oil is an extremely potent source of both EPA and DHA. In general, algae oil and fish oil have comparable omega-3 content. However, there are significant differences in the production, purity, and sustainability between these two supplements that may influence your choice.
Nutritional Benefits, Compared
There are several different kinds of omega-3 fatty acids, and both fish oil and algae oil contain EPA and DHA. These are often considered the most important omega-3s since they play direct roles in human health.
EPA, or eicosapentaenoic acid, is an omega-3 fatty acid that is thought to have anti-inflammatory properties.* DHA, or docosahexaenoic acid, is important for brain and central nervous system development. Together, these are thought to have a wide range of beneficial health effects in the body, including supporting heart, brain, joints, and skin health.*
While the presence of both kinds of omega-3s is beneficial to human health, the ratio of EPA to DHA that is present in a supplement can make a slight difference in how it supports the user’s health. For example, a supplement that is higher in EPA than DHA may be preferable for people who are interested in taking the supplement to benefit their heart health, while someone who is prioritizing their brain health and function may prefer a supplement that has a higher ratio of DHA to EPA.
There is not much evidence to suggest that fish oil and algae oil have inherently different ratios of EPA to DHA. In fact, fatty fish get their omega-3s from the source: microalgae! Because they eat microalgae as part of their diets, the omega-3 contents are fairly similar. Any significant differences will largely depend on how the manufacturer processes their products, rather than the natural omega-3 content in the oils themselves.
Other components
EPA and DHA aren’t the only nutrients found in fish and algae, there are other important unique nutrients that are present in fish oil vs algae oil, and vice versa.
For example, many fish-based sources of omega-3 also contain Vitamin D, the “sunshine vitamin” that plays a variety of roles in supporting brain, skin, and bone health. Some fish like salmon also contain a component called astaxanthin, a powerful antioxidant.
Meanwhile, microalgae produce nutrients through photosynthesis that make it a valuable part of any diet. Studies have shown that microalgae is a good source of various vitamins like B-complex vitamins, Vitamin A, Vitamin C, and Vitamin E. It’s also known to be a good source of minerals including potassium, iodine, iron, and calcium. Certain species of these aquatic organisms are also thought to have helpful antioxidants like carotenoids and xanthophyll, which can help support overall immune health. 
This isn’t necessarily to say that fish and algae oil always contain these nutrients. Ultimately, the presence or absence of these other nutrients depends on how the manufacturer purifies and processes their product. Many manufacturers prefer to create supplements that are “pure”, meaning that they are primarily interested in keeping the omega-3s and eliminating any other potential ingredients.
Absorption and Bioavailability
It’s worth considering how quickly your body can absorb those essential omega-3s, as well as how much of those nutrients your body can actually use.
Generally speaking, your body’s process of omega-3 absorption takes a couple of hours from consumption to delivery to your cells, with variations depending on your current health status, age, and metabolic speed.
Research so far doesn’t suggest that there are any major differences between algae oil and fish sources when it comes to the absorption of DHA. In a comparison between algae oil pills and cooked salmon, researchers found that the effects of both were about equal in improving DHA levels.
Interestingly, though, there is some evidence that the EPA from algae oil might be absorbed more quickly than from other sources, though this is not yet conclusive. For example, one small study found that males who consumed algae oil saw more rapid increases in their blood EPA levels than men who used a krill oil pill. However, more research is required on a larger scale to determine how universal this effect may be.
Purity, Contamination, and Sustainability
While there are certain differences in nutrition profiles between algae oil and fish oil, the two are fairly comparable in terms of their reported health benefits. However, the biggest difference between these two omega-3 supplements comes down to their purity, susceptibility to contamination, and how sustainable their production processes are.
Purity and contamination
The process of making fish oil is long and complex. It involves catching cold-water fish from the ocean, extracting the oils with processes like boiling or applying chemical solvents, and then shipping those extracted oils off to production plants around the world to be refined with more chemical processes. The oil is then put into capsules or containers, and then finally shipped off to the stores where you can buy them.
Unfortunately, this long journey presents some major issues as far as purity and contamination go. Because of its high-fat contents, fish oil is more subject to going bad than other kinds of supplements. The time alone that it takes from initial harvest to reaching your drug store’s shelves can increase the fish oil’s likeliness to oxidate and go rancid. The processing can also change the final product’s omega-3 fatty acid content.
The potential for mercury contamination is another major issue that leaves many people feeling iffy about consuming fish products. Mercury is a toxic heavy metal that is found naturally in the earth but increases due to human industrial practices and pollution. Aquatic species like fish and krill can ingest mercury, and it passes along through the food chain. Large fish like mackerel, tuna, and swordfish are particularly susceptible to mercury overload since they’re at the top of the food chain. While the refining process can eliminate most of the mercury that might be found in fish, and though the reported levels of mercury found in fish oils are often very small, even very small amounts of mercury can be dangerous over time as it accumulates in the body.
Meanwhile, oil from microalgae can be better monitored throughout the entire process, from initial growth to the final product. Microalgae is fairly easy to grow, which means that it can be grown in isolated facilities that are less susceptible to potential contamination from other marine sources. It also greatly reduces the risk of mercury contamination. In fact, some species of microalgae are even known to help detoxify mercury sources!
Sustainability
One of the biggest reasons to choose algae oil over fish oil is because of its comparable sustainability. 
The global fishing industry is devastating for marine life. Overfishing for fish oil and other fish products produces huge amounts of bycatch and environmental damage that is leaving the oceans vulnerable to the effects of climate change.
Algae, meanwhile, is superior when it comes to sustainability. When compared to fish, microalgae require very few resources to thrive. All it really needs is sunshine and saltwater. Because algae oil can be isolated and grown outside of the ocean, the impacts on marine life and natural ecosystems is minimized.
Considerations and Recommendations
We’ve gone over several of the similarities and differences between fish oil and algae oil in this article. To summarize:
- Microalgae produce both EPA and DHA via photosynthesis and are, therefore, a primary source of these valuable nutrients. Fish get their EPA and DHA from consuming microalgae.
- The omega-3 contents of EPA and DHA appear to be fairly comparable between fish oil and algae oil.
- The absorption and bioavailability of the omega-3s in fish and algae oil also appear to be fairly comparable, though there is some evidence that we may be able to absorb EPA more quickly from algae oil.
- The key differences between fish oil and algae oil come down to sustainability and purity.
- Fish oil is subject to contamination and rancidity because of its long processing time, and its production contributes to environmental damage and affects marine ecosystems.
- Algae oil is more sustainable since it can be isolated. Its growth can also be monitored from beginning to end.
Both algae oil and fish oil are great sources of omega-3s. However, algae oil shines when it comes to sustainability and purity. It is also suitable for most people, even those with dietary restrictions like fish allergies or plant-based eaters.
The bottom line:
- If your doctor specifically recommends it or if it is the most accessible option, choose fish oil.
- If you are vegetarian, or vegan, have a food allergy, and/or are interested in supplements that are produced with better purity and sustainability standards, algae oil pills are a better choice.
Make sure to speak with your doctor before starting any dietary supplement. They can help you make the best choice on supplements and dosages depending on your unique dietary needs and health goals.
