Should You Take a Fish Oil Supplement?

Here’s a look at what recent research shows about the benefits of taking fish oil when it comes to heart, brain, joint and eye health, since those are the most common and well-studied reasons people take them.

Do fish oil supplements boost heart health?

Diet-based studies in the 1970s linked higher omega-3 levels to a significant reduction in cardiovascular risk, especially stroke risk. Based on that, Natarajan says, there was a flurry of interest in “capturing that macronutrient in a pill to see if that similar efficacy could be achieved outside of food.”

But efforts to bottle the benefits haven’t panned out. While some studies show possible advantages, many large, randomized controlled trials failed to show clear cardiovascular benefits from fish oil supplements, Natarajan says.

At the same time, concerns emerged as studies linked high doses of fish oil to an increased risk of irregular heart rhythm. A 2021 meta-analysis published in Circulation found that people taking fish oil supplements had a 25 percent higher risk of atrial fibrillation compared with those who didn’t take them.

“Back in the day, I used to take over-the-counter fish oil,” says Dr. Andrew Freeman, director of cardiovascular prevention and wellness at National Jewish Health in Denver. “As time has gone on, the evidence now points away from it.… None of the professional society guidelines for cardiology recommend over-the-counter fish oil at this time.”

The only exception, Freeman says, is for patients with very high triglyceride levels, who may be prescribed a type of highly purified, prescription-grade fish oil with the brand name Vascepa (icosapent ethyl).

Do fish oil supplements support brain health?

Plenty of research shows that eating fish can protect memory, improve thinking skills and slow cognitive decline. But when it comes to fish oil supplements, the evidence is less clear, says Lynne Shinto, a naturopathic doctor and professor of neurology at Oregon Health & Science University.

So far, most randomized controlled trials have found no brain benefits among people who take fish oil capsules, she says. A two-year placebo-controlled study of older adults published in June 2026 reinforced that point. University of Southern California (USC) researchers found that fish oil supplements raised omega-3 levels in participants’ brains but did not improve memory, thinking or brain structure over two years. 

Shinto said it is a well-designed study but notes that it doesn’t answer every question. The participants took only high-dose DHA, not EPA, the other omega-3 fatty acid that helps reduce inflammation. They were also relatively young (mean age of 66 years) and had normal cognitive function when the study began. 

Shinto’s own research suggests there may be subgroups that respond differently. In a 2024 randomized clinical trial published in JAMA Network Open that she coauthored with Harvard researcher Gene Bowman, Shinto followed about 100 older adults over age 74 with no signs of dementia for three years. The study found that for most people, there wasn’t a significant benefit. But for a small group of people carrying the APOE4 gene, a genetic marker linked to higher Alzheimer’s risk, the supplements appeared to slow the degeneration of brain networks.

While Shinto is planning a larger clinical trial to confirm the results, she emphasizes that studies show that fish oil supplements are generally safe and have few side effects.

Patients interested in taking fish oil supplements for their brain health should first talk with their doctor to discuss their individual risk of atrial fibrillation.

Can fish oil help with joint pain and muscle strength?

Fish oil’s anti-inflammatory properties have made it a popular supplement among people hoping to ease joint pain or preserve muscle, and some research indicates it might be helpful.

For example, a 2023 meta-analysis of nine trials involving more than 2,000 people with osteoarthritis found that those who took omega-3 supplements reported less pain and better movement compared with those who took a placebo. Osteoarthritis is a common condition that occurs when the cartilage between bones breaks down, causing joint pain.

Fish oil supplements have shown “a lot of promise in terms of reducing cartilage degradation, reducing inflammation and probably improving outcomes,” says Stephen Cornish, a kinesiologist at the University of Manitoba in Canada who has studied fish oil’s effect on muscles, bones and joints.

However, results across human studies have been mixed, Cornish says, and more randomized controlled trials are needed. 

As for muscle strength, some small studies indicate that fish oil may help preserve muscle mass or improve muscle function, particularly in older adults. A meta-analysis led by Cornish in 2022 found that omega-3 supplements did not boost muscle mass but did improve lower-body strength and mobility in older adults, especially when combined with resistance training.

“One thing we are theorizing, and that other researchers have looked at as well, is that it may actually enhance neuromuscular communication … in terms of firing the muscle appropriately and firing it more forcefully,” Cornish says.

Can fish oil support eye health?

For years, people with dry eye disease were advised to take fish oil supplements because it was thought they could reduce inflammation and help lubricate the eye.

However, research on the benefits of fish oil for eye health has been mixed:

A government-funded, multicenter study published in The New England Journal of Medicine in 2018 found that omega-3 supplements were no more effective than a placebo (olive oil) in reducing dry eye symptoms, although patients in both groups showed improvement.

Separately, a 2023 review of 19 studies found that high-dose omega-3s, particularly those high in EPA, improved tear production and reduced overall symptoms. The authors stressed that some of the results were inconsistent and more research is needed.

Who should not take a fish oil supplement?

Fish oil supplements are generally not recommended for people who have fish allergies. (Plant-based omega-3 supplements made from algae oil are available.)

Fish oil supplements can also cause problems if you take certain medications. They may increase the effects of blood thinners and blood pressure medications, raising the risk of bleeding or lowering blood pressure too much.  Limited research indicates that fish oil supplements could interfere with certain cancer treatments. 

Studies show that typical omega-3 supplements do not increase the risk of bleeding after surgery, but some surgeons still recommend stopping them before a procedure. Ask your doctor what he or she recommends. 

Research shows no clinically significant negative interaction between fish oil supplements and antidepressants such as SSRIs. In fact, some studies suggest omega-3s may even enhance the effects of antidepressants in some people.

Always check with your doctor before adding a supplement, especially if you take prescription medications.

What to know if you want to try an omega-3 supplement

If you’re interested in trying a fish oil or another omega-3 supplement, here are a few things to keep in mind:

• Stick to safe doses. Health officials recommend consuming no more than 5 grams per day, or 5,000 milligrams of EPA and DHA combined from dietary supplements. A typical fish oil supplement provides about 1,000 mg of fish oil, containing 180 mg of EPA and 120 mg of DHA, but doses vary widely.
• Look for third-party certification. What’s on the label isn’t always what’s in the bottle, so look for third-party seals (like NSF International, USP or ConsumerLab.com) that certify purity and quality.
• Take it with food. Research indicates fish oil is better absorbed when taken with a meal, especially one with some dietary fat.
• Store it smartly. Keep the bottle tightly sealed and away from heat and humidity, which can turn the oil rancid.

Even if you follow these recommendations, experts stress that eating actual fish a few times a week is always a better bet for long-term health than relying on a supplement, especially if it’s part of a healthy diet rich in fruits, vegetables, whole grains and healthy fats.

“What we’ve learned is when we just focus on one individual nutrient or one individual food, it never stands the test of time,” Lichtenstein says. “That’s because it’s the whole pattern [of what you eat] … that really makes the difference.”