What Is Fish Oil, Really? And Should I Take It For Health Benefits?

Fish oil can help deliver omega-3 fatty acids to people who get subpar levels of the nutrient. And, while you can get omega-3 fatty acids from eating fish, most people don't get enough to meet their daily needs—including strict vegans and others who choose not to (or simply cannot) include fish in their diet. This is where high-quality supplementation comes into play. 

But what is fish oil, exactly—and who should consider it? Here's what you need to know.

Fish oil is the concentrated and purified oil derived from the tissue of oily fish. Fish oil can be delivered in a variety of different biochemical structures, but the main forms are triglyceride, ethyl ester, and phospholipid, explains Jessica Cording, M.S., R.D., CDN, a registered dietitian, health coach, and the author of The Little Book of Game Changers. 

"To compensate for this well-known difference in bioavailability, you have to consume ethyl ester (aka EE) forms of fish oil with some fat, like a meal. You don't have to do that with triglyceride fish oil, the native form of the fat," explains nutrition scientist and dietitian Ashley Jordan Ferira, Ph.D., RDN.

"Fish oil is rich in the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)," says Lisa R. Young, Ph.D., RDN, adjunct professor of nutrition at NYU Steinhardt. Fish that are especially rich in omega-3s include herring, anchovies, tuna, mackerel, sardines, and salmon, she points out. 

Fish oil has plenty of incredible health benefits, thanks to its concentrated dose of omega-3s. 

For starters, these oils "have been shown to promote a healthy inflammatory response and support heart and blood circulation function,"* says clinical biochemist and renowned father of functional medicine Jeffrey Bland, Ph.D., FACN, CNS. The omega-3s in fish oil are also "used by the immune system to help modulate a healthy immune response in all organs of the body,"* he adds. 

The EPA and DHA in fish oil are essential for a healthy heart; in fact, a 2019 science advisory from the American Heart Association (AHA) states that research suggests EPA and DHA support healthy levels of triglycerides (i.e., a type of fat in your blood).* What's more, according to the FDA2, consuming at least 800 milligrams of EPA and DHA together daily may even lower your risk of developing coronary heart disease (CHD) by lowering blood pressure.*†

DHA is also a critical nutrient during pregnancy, as it's involved in the healthy development of the central nervous system.* Worth noting: A 2018 3Nutrients3 study3 linked higher DHA levels during pregnancy with better problem-solving skills in babies at 12 months, demonstrating how essential proper DHA intake truly is during pregnancy (for both baby and mother).* 

If heart and healthy pregnancy benefits aren't enough to turn your head, a 2019 meta-analysis from Translational Psychiatry reveals that supplementing with omega-3s has been linked to healthy mood balance and resilience4 as well.* Finally, the omega-3s found in fish oil can support your musculoskeletal health by helping regulate bone turnover to promote calcium balance5 and bolstering joint mobility and comfort6.* 

"The science to date demonstrates that marine omega-3s EPA and DHA are whole-body relevant and important for every cell," concludes Ferira, adding "That's why it's genuinely concerning how underconsumed these healthy fats are in our nation."

Whether or not you should take fish oil really depends on your individual goals, Cording explains. "I will often recommend [a fish oil supplement] for someone who is trying to conceive or is already pregnant," she says. "You definitely want to supplement during those times unless you're eating tons of oily fish." (That would be rare for most pregnant women trying to be careful about contaminants like heavy metals.)

Cording also suggests fish oil for individuals that just don't like fish. "Fish oil can be very helpful to cover [omega-3] nutrient gaps," she says.

Speaking of being mindful of daily nutrition needs, Ferira shares, "a high-quality omega-3 supplement delivering EPA and DHA in meaningful amounts is a true daily essential, right up there with an effective D3 supplement and a comprehensive multivitamin."

Furthermore, if you're looking to promote healthy triglyceride levels and support overall heart health in a targeted way, Young says that thoughtfully formulated fish oil can help.* 

(Worth noting: mbg's omega-3 potency+ provides 1.5 grams of triglyceride EPA and DHA in each serving—a dose that's strong enough to support these needs.)*

There is currently not a set recommendation for fish oil dosage, specifically, but there are definitely relevant guidelines. (We dive into the specifics of fish oil and omega-3 dosage here, if you're interested in learning more.)

The Dietary Guidelines for Americans recommends that people eat 8 ounces (about two servings) of fish per week, which is approximately 250 to 500 milligrams of combined EPA and DHA per day.

While the AHA echoes that two-fish-weekly serving as a healthy starting point (that we're not achieving as a nation), they also recommend increasing that daily intake to 1 gram (1,000 milligrams) or more of EPA plus DHA to promote greater heart-health benefits.*

A major complaint of taking fish oil is flavor and "fishy burps," but a high-quality fish oil should not have a "fishy" aftertaste, Bland says. 

Ferira couldn't agree more, adding that "fish oil shouldn't make you burp…that's not a good sign of the quality of the oil." What's more, as she previously shared on the mindbodygreen podcast, "If your fish oil smells funny—fishy, sour, or it's very yellow—these are signs of bad purity. It's a sign of oxidation."

As far as side effects go, "There are no serious side effects from taking a lot of fish oil other than mild gastrointestinal concerns at high doses," Bland says. 

However, out of an abundance of caution, people who are taking blood-thinning medications or who have specific health concerns related to bleeding should consult their doctor before taking fish oil to make sure their dosage doesn't interfere with their medications, Bland notes. That's because omega-3s can affect platelet activity7.*

So what does this omega-3 and platelet relationship mean for everyday use of fish oil? "In reality, the blood-thinning effect of fish oil actually occurs at absurdly high levels of EPA plus DHA, 10 grams plus, which by the way, no supplement even comes close to containing," Ferira previously shared with mbg.

That's a very important dose distinction since in fact, "omega-3 supplements are playing in the 200- to 1,800-milligram range of EPA plus DHA 99% of the time," Ferira adds. In other words, the blood-thinning consideration level for most people is up to 20 times the typical daily dose of a fish oil supplement (so the average person shouldn't be concerned).

For a full explainer on the potential side effects of fish oil, you'll want to check out this full explainer.

Fish oil can help you meet your daily marine omega-3 needs and can be an important supplement for many people as a daily essential and even for specific life stages and functional health areas—like those who are pregnant or looking to support cardiovascular health.* 

With 1.5 grams (1,500 milligrams) of EPA plus DHA in each serving (just two gelcaps), mbg's omega-3 potency+ is a stellar way to meet your daily omega-3 PUFA needs while serving as a powerful daily essential for heart, brain, joint, eye, immune, perinatal, and overall health.*

Our sustainably sourced fish oil supplement is derived from wild-caught anchovies from the chilly waters of the South Pacific (off the coast of Chile). Our fish oil also earned the unique distinction of third-party ORIVO certification for authenticity, verifying fish species and origin via DNA fingerprinting technology.

For other incredible fish oil options, check out mbg's roundup of the best omega-3 supplements on the market!