Background

Today we answer a simple question with a nuanced answer: can omega-3s improve strength or endurance performance? Mechanisms look promising; real-world performance is the test. Let’s unpack both.

Reasons to believe it can

  • Reduce inflammation, which may mean fewer injury issues and better training continuity.
  • Support immune function, so illness disrupts fewer sessions.
  • Aid recovery in general.
  • Enhance the anabolic response to amino acids.
  • Improve sleep quality.
  • Lower the oxygen cost of exercise.

These ideas make sense mechanistically. The key question is whether they translate to measurable performance gains.

Endurance

Running

Study 1: “Effects of 12 Wk of Omega-3 Fatty Acid Supplementation in Long-Distance Runners.”

  • 26 runners took high-dose omega-3 (~2.2 g EPA and ~1 g DHA) or placebo (MCT).
  • Omega-3 index rose from 5.8% to 11.6%.
  • VO₂max and running economy improved in the omega-3 group.
  • However, 1.5 km time-trial performance did not improve vs placebo.

Study 2: “Omega-3 fatty acids supplementation improves endothelial function and maximal oxygen uptake in endurance-trained athletes.”

  • Three weeks of supplementation in elite cyclists improved endothelial function and VO₂max.
  • They did not test performance directly, so findings are mechanistic rather than outcomes-based.

Study 3: “Intrinsic heart rate recovery after dynamic exercise is improved with an increased omega-3 index in healthy males.”

  • ~150 mg EPA + ~550 mg DHA for eight weeks.
  • Average exercise heart rate at a fixed intensity decreased; heart rate recovery improved.
  • Again, these markers suggest potential performance benefits, but the study did not measure performance.

Study 4: 2020 narrative review.

  • After surveying the literature, the authors concluded omega-3s do many things that should help endurance.
  • The gap: very few trials measure actual performance; the runner study above found no time-trial benefit.
  • The 1.5 km test is short, so longer efforts might show different results.
  • If a benefit exists, it is likely small.

Strength

Strength training

Study 1: “Lack of evidence for Omega-3 fatty acid supplementation in enhancing lean mass, muscle strength, and physical function in healthy adults and clinical populations: An overview of reviews.”

  • Included 33 reviews (11 cancer, 19 general population without cancer, 3 mixed).
  • Lean mass: 4/16 reviews found some benefit; 3 of those focused on older adults.
  • Strength: 1/14 reviews found benefit.
  • Overall, evidence for these populations is weak at best.

Study 2: “International Society of Sports Nutrition Position Stand: Long-Chain Omega-3 Polyunsaturated Fatty Acids.”

  • Narrative/consensus with an athletic lens.
  • Across studies:
    • Little to no effect on muscle growth.
    • Small, positive effects on strength on average.
    • Effects may be smaller in people who train seriously with resistance work.

Interpretation

  • Omega-3s do not appear to change body composition in research, unless indirect benefits happen to carry over for an individual.
  • Small performance benefits likely exist on average. Strength has more direct evidence; endurance mostly shows promising mechanisms rather than clear performance wins.
  • People with low baseline omega-3 status are more likely to benefit than those who already have high levels.

How to take

Fish oil

  • Animal-based: Eat fish 2–3 times per week, with at least one higher-fat option like salmon.
  • Supplementation: A triple-strength fish oil can make dosing practical; 2–3 capsules per day aligns with the higher intakes discussed. Going lower still moves you in the right direction, and returns likely diminish as you approach “optimal.”
  • Plant-based: Choose microalgae-based EPA/DHA supplements. These provide the direct forms used in studies. ALA sources (e.g., flaxseed oil) rely on conversion to EPA/DHA, which is inefficient, so they are not equivalent for this purpose.

Wrap-Up

This is our final episode with Leah as co-host. From next week, Aidan will relaunch with a new co-host, Torwen. Leah will continue the PlantstrongCo podcast, so please check it out if you enjoy her work here. We’re grateful to everyone who has listened over the last four years.

Show Notes

Relevant Studies

Relevant Podcasts