The Surprising Role that Fish Oil Plays in Muscle Hypertrophy

The Surprising Role that Fish Oil Plays in Muscle Hypertrophy

(Last Updated On: April 12, 2019)

Sources of Omega-3 acid and fish oil (salmon, shrimps, Omega-3 pills)

One of the more popular supplements men and women take these days is fish oil supplements. Fish oil is the oil derived from fatty fish, including wild salmon sardines, etc. The potential health benefits of fish oil come from the long-chain omega-3’s they contain. These omega-3’s are primarily EPA and DHA, a type of fatty acid linked with anti-inflammatory properties. In contrast, most of the polyunsaturated fats in the Western diet are omega-6’s. Some experts believe this imbalance is fueling a rise in chronic heart problems, including cardiovascular disease, because of omega-6’s fuel inflammation. Omega-6’s are abundant in processed cooking oils, particularly soybean and corn oil. In contrast, most people in Western countries get little fatty fish to compensate for the omega-6’s they consume.

As you might know, inflammation plays a role in a variety of health problems, including cardiovascular disease. One reason people take fish oil capsules is in hopes of lowering their risk of heart disease, heart attacks, and stroke and to make up for the imbalanced omega-3 to omega-6 ratio characteristic of the Western diet. Omega-6’s are abundant in processed cooking oils, fast food, and packaged food.

Although not all research show benefits, studies suggest that long-chain omega-3’s lower the level of blood fats called triglycerides that are linked with a higher risk of heart disease. In addition, studies show that cultures who eat lots of fatty fish have lower heart disease rates. Still, despite the popularity of fish oil capsules, there’s no definitive evidence that taking them actually reduces the risk of heart attack or stroke.

However, due to the anti-inflammatory effect, the long-chain omega-3’s in fish oil may have other health benefits and research is continuing to look into this. One potential benefit that’s particularly intriguing to people who train with weight is that the omega-3’s in fish oil might enhance muscle hypertrophy by turning on pathways that ramp up muscle protein synthesis. That would certainly be of interest to bodybuilders, both amateur and professional.

Fish Oil, Omega-3’s, and Muscle Hypertrophy

As you know, the muscle mass you have is determined by the rate of muscle protein synthesis versus muscle protein breakdown. Muscles are always in a state of turnover. If muscle protein breakdown exceeds muscle protein synthesis, you lose muscle mass. (catabolic state), whereas the opposite is true if protein synthesis exceeds breakdown (anabolic state). Instead, you’ll gain muscle.

Unfortunately, as we age, we naturally lose muscle mass. What’s more, once past the age of 60, anabolic resistance becomes a problem, a condition where muscles become less responsive to anabolic signals, like protein and strength training, that tell them to grow. Anabolic resistance makes it more challenging for older adults to build muscle size and maintain the muscle they have.

Omega-3’s and Anabolic Resistance

Can the omega-3’s in fish oil capsules help counter anabolic resistance? In one study, researchers divided healthy adults between the ages of 65 and 81 into two groups. One group supplemented with long-chain omega-3’s from fish oil while the other got an equivalent dose of corn oil for 8 weeks. Over the course of the study, the researchers measured muscle protein synthesis in response to infusions of amino acids and insulin.

Interestingly, the group who took the long-chain omega-3’s tripled their rate of muscle protein synthesis relative to the control group that got corn oil. Does this only hold true for older people with anabolic resistance?  A follow-up study of younger people between the ages of 25 and 45 also showed a boost in muscle protein synthesis in response to long-chain omega-3’s as well.

How might omega-3’s boost muscle protein synthesis? It’s possible that their anti-inflammatory effect is a factor. Reducing inflammation in the muscle may improve insulin signaling and make it easier for muscle cells to ramp up protein synthesis. Another theory is that long-chain omega-3’s boost blood flow to the muscle after a meal, thereby more efficiently supplying muscles with the building blocks they need to grow.

Improvements in Muscle Quality and Body Composition?

In another randomized-double-blind, placebo-controlled study, researchers asked 50 older men and women (age 70 plus) to take part in a lower-body strength training program. The participants trained twice weekly for 18 weeks. One group took 3 grams of fish oil daily while the other took an equivalent amount of safflower oil to serve as a control. In the study, women who took the fish oil, but not men, showed improvements in muscle quality independent of muscle mass. Researchers in this study believe that the omega-3’s in fish oil could be exerting their benefits at the neuromuscular junction or by enhancing the contraction of fast-twitch muscle fibers.

Other small studies suggest that supplementing with fish oil could improve body composition in another way – by reducing waist circumference. Who wouldn’t like a slimmer waistline?

The Bottom Line

Fish oil may modestly enhance muscle protein synthesis with greater benefits in older people. One possibility is that the omega-3’s in fish oil might help older individuals counter anabolic resistance and reduce the loss of muscle tissue that goes along with it. However, you don’t have to take a fish oil supplement to get these benefits. You can also get long-chain omega-3’s by eating fatty fish, like wild-caught salmon, twice per week. Fish is also a good source of protein, which is important for muscle hypertrophy.

If you do choose a fish oil supplement, buy from a reputable manufacturer and make sure they use molecular distillation to remove impurities. Fish, especially large fish, absorb toxins from the environment, including heavy metals, dioxins, and PCB’s, although independent testing of fish oil supplements doesn’t show significant contamination for most brands.

If you eat fish, refer to a chart that tells you how much of each type of fish it’s safe to eat on a weekly basis. Some fish are more prone to accumulate contaminants than others. If you’re pregnant, talk to your physician about whether you should eat fish and in what quantity.



Physiol Rep. 2016 Sep; 4(18): e12958.Published online 2016 Sep 20. doi:  10.14814/phy2.12958.
Int J Cardiol. 2009 Jul 24;136(1):4-16. doi: 10.1016/j.ijcard.2008.03.092. Epub 2008 Sep 6.
Curr Nutr Rep. 2016 Jun; 5(2): 99–105.Published online 2016 Apr 2. doi:  10.1007/s13668-016-0161-y “Fish Oil and Resistance Training: Effective for Older Adults?”


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