Omega-3s and fish go hand in hand, so omega-3 supplements and fish oil must be one and the same right? Getting critical, healthy omega-3 fatty acids from fish and fish oil is a definite reality, but strict vegans and those with fish allergies would be devoid of omega-3s if seafood were the only source available. The truth is, there’s a lot of omega-3 supplements out there, and some aren’t as fishy as you might think.

Are Omega-3 and Fish Oil the same?

Not exactly. Registered Dietitian Jess Cording, M.S., R.D., CDN, explains all fish oil supplements can provide omega-3s, but not all omega-3 supplements are from fish oil.

“There’s three types of omega-3 fatty acids,” Cording she says; “ALA, DHA, and EPA. ALA is a plant source, and EPA and DHA are both found in animal products – primarily fish.” Oily fish, such as tuna, anchovies, salmon, mackerel, and sardines, are especially rich in EPA and DHA, which is why they’re often featured in fish oil supplements.

Further, research reveals that most of the omega-3 health benefits come from EPA and DHA rather than plant-sourced ALA (in other words, they’re not interchangeable).

Although our bodies technically have the ability to convert small amounts of ALA from food sources into EPA and DHA, the process is very inefficient and variable (because of gender, age, etc.), so it’s best to also consume some EPA and DHA to ensure you’re reaching optimal omega-3 levels.

With so many fish oil and omega-3 supplements on the market and diverse factors like source, form, bioavailability, quality, traceability, and sustainability, there’s a lot to consider.

Types Of Omega-3 Supplements

Luckily for vegans and people with fish allergies, fish oil isn’t the only form of omega-3 supplement available to consumers. There are a variety of supplements that can help you boost your omega-3 intake.

Algae Omega-3

Omega-3 supplements with algal (algae) oil is Cording’s first choice for her plant-based patients. “I often recommend an algae-based supplement for them if fish is not an option,” she says. Like us, fish aren’t able to produce their own EPA and DHA. Instead, they get their omega-3s by consuming microalgae, so algae is a primary source of both DHA (mostly) and EPA (a little bit) for those who cannot or choose not to eat seafood.

A few caveats for algal oil include the omega-3 contribution, cost, and balance. As nutrition scientist Ashley Jordan Ferira, Ph.D., RDN, shares, “Algal oil is one of the most expensive options in the omega-3 market, and while it’s an obvious solution for key segments with allergen concerns and vegan lifestyles, its omega-3 balance is not ideal. Algal oil is heavily skewed on DHA, with minimal EPA contributions, thus, the EPA plus DHA balance and totality is inferior when compared to a high-quality fish oil supplement.”


Flaxseed oil is another plant-based option for omega-3 supplementation. Flaxseed is high in ALA (the plant-sourced essential omega-3 fatty acid) and can help provide omega-3s for those who avoid meat and seafood. While there isn’t an official recommendation for daily EPA or DHA intake (yet), the National Academies recommend that men and women get 1.6 grams and 1.1 grams of ALA per day, respectively.

It can be difficult to get enough of the other unique, science-backed omega-3s (EPA and DHA) when eating mostly plants. “The body can make some EPA and DHA from ALA, but it’s not an efficient process,” Cording reminds us. “So even though consuming only plant sources can help you meet your needs, it can be challenging to meet your needs without a supplement if you’re on a plant-based diet or you don’t regularly consume fish for whatever reason.” (And by regular fish consumption, we mean at least two times a week.)

Fish Oil

Fish oil is the concentrated and purified oil from the tissue of oily fish. There are a variety of forms this fat can be delivered, based on how the fish oil is processed. (By “form,” we mean the type or chemical structure of the omega-3 fats.)

The main forms are triglyceride, ethyl ester, and phospholipid. The native form of fat is triglyceride for fish and humans. It’s also the most bioavailable form (i.e., more easily absorbed and accessible to your cells).

“For fish oil, the triglyceride form is where it’s at,” Ferira shares. “The triglyceride form is how marine omega-3 fatty acids EPA and DHA are found in the fat of the fish. and how we consume and absorb fat in our diet. In other words, it’s the form found in nature and native to the fish.”

Fish oil comes from many types of fish, including salmon, anchovies, tuna, sardines, herring, and mackerel. Cording recommends choosing fish oil derived from a thin fish (such as anchovies or sardines), as those are less likely to have high levels of mercury and other metals than bigger fish. Ferira explains that, of course, this is not a concern when taking top-notch fish oil, as “high-quality fish oil products are highly purified to achieve negligible trace levels of contaminants like heavy metals.”

Krill Oil

Krill are small, shrimplike crustaceans that, like fish, mostly eat microalgae. If you’re a marine biology aficionado, you may know that many fish and mammals like whales, depend on krill as a diet staple.

Krill oil contains EPA and DHA in the form of triglycerides and phospholipids. Interestingly, krill have a very short lifespan and don’t accumulate many toxins. Additionally, krill oil contains very small levels of an antioxidant called astaxanthin that provides health benefits and buffers it from oxidation.

What Is The Best Type Of Omega-3 Supplement?

Omega-3 supplements are not one-size-fits-all. For those who don’t eat fish by choice or because they cannot (e.g., because of an allergy), there are some viable options derived from plants. “Algae is great, flax is great—but again, they are not quite as efficient,” Cording reminds us.

For plant-based folks, eating lots of ALA-rich foods and finding a high-quality omega-3 supplement to meet the recommended intake for ALA is important for whole-body health.

If you’re in the 10% of Americans who actually eat two or more servings of oily fish per week, you might not need to take a supplement every day to meet baseline levels of omega-3s. Or you may still leverage an omega-3 supplement to meet the higher levels recommended by the American Heart Association for cardioprotection (i.e., 1 gram or more of EPA and DHA daily).

If you’re in the other 90%, you’re definitely not alone, and there’s no need to stress. There are high-quality omega-3 supplements out there to help you thrive on daily omega-3 intake so you can reap the benefits, just like avid fish-eaters.

If you’re feeling overwhelmed by the plethora of omega-3 supplements to choose from, Ferira recommends you focus on these five factors:

  1. A pure, bioavailable omega-3 source
  2. Potent dosage of omega-3 fatty acids
  3. Purity and quality control (aka a product that won’t go rancid)
  4. Brand transparency and sustainability
  5. A short, clean list of other ingredients

The Takeaway

Whether you’re getting your omega-3 fats from fish, algae, flax, or krill, the important thing is that you’re supporting your health with omega-3 fatty acids. Omega-3s do so much for our bodies (from our cells and organ systems to the whole body) and while there are many omega-3 supplement options out there, experts agree that omega-3 potency is what to look for.