For a variety of reasons, almost everyone is low on omega-3s. It doesn't get the attention it deserves, but I think the most underrated supplement might just be omega-3 fatty acids.
I think the most underrated supplement might be Omega 3 fatty acids (I love Momentous brand). Let's highlight a few of the weirdest and coolest studies on them!
Why I'm Writing Today
Why I'm writing? I had a lot of caffeine at 5 AM and I GOTTA EXPRESS MY FEELINGS ABOUT FISH OIL. This is how Kerouac felt when he took a bunch of drugs and wrote "On The Road" in a continuous 120-foot scroll.
The other reason I'm writing this article is a 2024 meta-analysis called "Omega-3 supplementation reduces aggressive behavior: A meta-analytic review of randomized controlled trials." It summarized 29 randomized control trials with 3918 participants to find that Omega-3s seem to reduce aggression across age, gender, recruitment sample, diagnoses, treatment duration, and dosage. The theorized mechanism was that Omega-3s may lower brain inflammation, enhance communication between brain cells, and boost the production of mood-regulating neurotransmitters like serotonin.
The authors were writing with their eyes set on the criminal justice system. But that conclusion really tickled my performance senses too. If we theorize that fatigue resistance is a nervous-system-driven process, then enhancing brain performance could also be a gateway to endurance generally.
There is a whole world of Omega-3 research outside of athletics that shows weird connections to cognition, mental health outcomes, behavior, blood pressure, and basically any other variable you can think of. Anything that touches that many parts of physiology must also touch performance, right?
Athletic Research
And Omega-3s have decades of research for athletes, more than almost any other supplement. There seems to be a new review study every year on their strange benefits! First, athletes are chronically lower in Omega-3 levels. One 2019 study on 138 football players found that 34% were at high risk of low levels, 66% were at intermediate risk, and 0 were at low risk. A 2020 study on a broader cohort of collegiate athletes found that only 6% consumed the recommended amount of Omega-3s per day (500+ mg).
And most interestingly, a 2019 study found that weekly mileage had a negative relationship with Omega-3 levels. A 2025 review study followed up with a scary conclusion: athletes are at extreme risk of low Omega-3 levels, below those shown to contribute to health issues in other studies. Perhaps fatty acid utilization by endurance athletes means that Omega-3 levels are at a higher risk of dropping.
(This is a quick aside, but a 2023 study on Omega-3 levels in elite female athletes found the usual low results. The authors cited that one of the main barriers for 38% of the women was inadequate "cooking skills." The lead author of the study was named "Matthew," and I hope Matt had a pull-out couch to sleep on after he published that study.)
Why do Omega-3 levels even matter?
Here, instead of a scientific article, I want to defer to the US Anti-Doping Agency. USADA seems to have a general public-facing view that almost all supplements are unnecessary, and still they say that Omega-3s may:
Lower blood pressure
Reduce triglycerides
Slow the development of plaque in the arteries
Reduce the chance of abnormal heart rhythm
Reduce the likelihood of heart attack and stroke
Lower inflammation
Lessen the chance of sudden cardiac death in people with heart disease
Potentially reduce muscle soreness after exercise
USADA goes on to say: "From a nutrition standpoint, it's important to understand that a fish oil supplement will never be as efficacious as simply eating fish high in omega-3 fatty acids." More like efFISHcacious, am I right? If The Feed isn't selling Colorado mountain salmon recovery smoothies, it's a missed opportunity.
An incredible summary comes from Knowledge is Watt, a wonderful newsletter on cycling performance. The author cited enhanced mitochondrial function, increased red blood cell transport (via a fascinating "deformability" increase), improved nitric oxide and endothelial function, and anti-inflammatory effects.
My guess is that almost every pro cyclist is taking an Omega-3 supplement, depending on their fish consumption, but I have no inside information. I'm often asked where I would teleport if I could only go to one place. And the answer is Tadej Pogacar's medicine cabinet.
Performance Questions
That's all well and good, but what about performance? If it's this miracle supplement, we should see it in STONE COLD RESULTS, right? That gets a bit tricky, since Omega-3 supplementation is usually a light physiological nudge over months, rather than a huge push that can be isolated over days and weeks. We're not talking about bicarb here! And there is evidence that very high doses may be dangerous, contributing to A-fib heart rhythms, so researchers can't apply hero doses to enhance the effect size.
JUST KIDDING! The studies also show some interesting performance benefits. A 2022 study on a 12-week supplementation protocol found a big increase in Omega-3 levels (into the "low risk" cohort) and an improvement in running economy. If it promises to safely and healthily improve my running economy, I will blow a sardine.
A 2025 study found Omega-3 supplementation reduced submaximal exercising heart rate (a change I see personally). A 2008 study on cyclists found that fish oil "may act within the healthy heart and skeletal muscle to reduce both whole-body and myocardial O2 demand during exercise."
There are dozens of studies on this topic, all with varying results. So let's usher in a few of the annual Omega-3 review studies and see what they have to say, because we don't got time for all that crap. A 2024 review pointed toward increased injury prevention and recovery rates. Another 2024 review found potential increases in muscle strength. A 2023 review found benefits for "controlling inflammation, supporting nervous system function, maintaining muscle mass after injury, and improving training adaptation." A 2020 review put it together:
"This review identified evidence to support a role of EPA/DHA in improved performance such as enhanced endurance, markers of functional response to exercise, enhanced recovery or neuroprotection... In general terms there seems to be an effect of supplementation duration, with favorable outcomes appearing more consistently after approximately 6–8 weeks.... Given that EPA/DHA are considered safe up to 5 g per day there seems little harm in recommending EPA/DHA, even when further larger studies with optimal design are needed to confirm these initial results."
My personal story: Omega-3 supplementation seems to directly affect resting heart rate overnight (usually 1-3 bpm lower with consistent supplementation) and heart rate during activity. Because the changes are so gradual, I can't really isolate the performance impacts. But I was taking them before all of my breakthrough races, and I guarantee I was low when I was younger. It may surprise you, but Megan and I aren't cooking krill very often.
My verdict: the neuroprotective effects might be most powerful of all, with some changes in fatigue resistance mechanisms over time that are supported by improved cardiovascular performance.
Takeaway
There are always small risks with any supplement. Maybe it could mess with electrical signaling in the heart at high doses, or maybe you take it without enough water and your burps smell like low tide on the bayou. But for now, Omega-3s seem like one of those easy interventions that most athletes should be considering.
I personally take Momentous Omega-3s, but there are a ton of good options. Check some out here. Make sure they're NSF for Sport or Informed Sport certified so you know you're getting what the label says, and don't overdo it. Sardine blowing optional.
