How omega-3 fatty acids and fish oil affect performance and recovery for running, OCR, and endurance sports
Thomas Solomon, PhD.
Updated onReading time approx 7 minutes (1400 words).
What you’ll learn:
Oily fish, fish oil supplements, algae, and some seeds and nuts provide omega-3 fats called DHA and EPA, which help keep your brain, eyes, immune system, and muscles working properly.
If you rarely eat foods that contain DHA and EPA, then an omega-3 or fish oil supplement might be helpful to plug that gap in your usual diet.
A daily omega-3 or fish oil supplement is likely to reduce muscle soreness and help restore your normal range of motion after hard, muscle-damaging exercise.
But a daily omega-3 or fish oil supplement is unlikely to boost your running or endurance performance, unless you are older (around 55 years or more) and/or you have low intakes of DHA and EPA.
Curious about the how and why? Scroll down for the details, the nuances, and the nerdy bits.
The information I provide is not medical advice. Omega-3 fatty acids can have side effects and might interact with other drugs, nutrients, and medical conditions (see here). If you are unsure, always consult your doctor to ensure that a specific supplement is safe for you to use.
What are omega-3 fatty acids and fish oil?
Fish oils are rich in DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid). These are long-chain polyunsaturated omega-3 fatty acids found in oily fish like salmon, herring, mackerel, and tuna, and in predatory fish that eat oily fish (for example, swordfish, shark, tuna). DHA and EPA are also found in algae and in relatively high amounts in flax seeds, chia seeds, hemp seeds, and walnuts.
In the body, DHA and EPA have several jobs. EPA mainly acts as a building block for signalling molecules called prostaglandins and leukotrienes, which help control inflammation and immune function. DHA mainly acts as a structural component in the brain’s cortex, the skin, and the retina in the eye. Both EPA and DHA are important, but they are not classed as essential fatty acidsEssential fatty acids are fatty acids that must be obtained in our diet because our body cannot synthesise them in sufficient quantities to maintain normal bodily function. because our body can make them when we get enough of another omega-3 called alpha-linolenic acid (ALA). ALA is one of the two essential fatty acids in humans (along with linoleic acid) and is found in foods like chia seeds and flax seeds. But in humans, the conversion from ALA to EPA and DHA is pretty inefficient, which is why guidelines encourage us to eat foods that already contain ALA, DHA, and EPA.
Because omega-3 fatty acids are found in several common foods, you may have been getting a decent dose for years without really thinking about it. And, because many of us grew up under the “nutritional wisdom” of our parents, you might even remember being chased around the kitchen with a spoonful of cod liver oil. (Note: Cod liver oil is rich in DHA, EPA, and vitamins A and E; and, it tastes like sh*t — I absolutely hated that as a kid.) But many people eat very little fish or very few seeds and nuts, and their overall diet might be kinda subpar. For those folks, it is likely that they are not getting much DHA, EPA, or ALA at all. That is one big reason omega-3s and fish oils have become popular supplements, and why supplementation may be necessary for people whose diets lack foods containing DHA, EPA, and ALA. On top of that, it is hard to miss the constant marketing that sells fish oil as the secret sauce for athlete recovery and performance — which raises the important question…
What is the scientific evidence on omega-3 and fish oil’s impact on athletic performance?
Please note that this summary is about exercise performance/recovery, not disease risk, prevention, or treatment. To go deep on the effects of omega-3s (DHA and EPA) or fish oils on general health, please check out examine.com/supplements/fish-oil and examine.com/supplements/omega-3. I consider Examine a carefully-researched and trusted resource. (For full disclosure, I’ve worked as a researcher and medical writer for Examine since October 2022, but do not receive royalties/bonuses for these referals.)
The exact “requirement” for EPA, DHA, ALA, and linoleic acid is not known, but based on population averages, the Adequate Intake (AI)Adequate Intake is the level of daily intake for a specific nutrient that may ensure nutritional adequacy in most people without health conditions when there is insufficient evidence to develop an Estimated Average Requirement (EAR) and, therefore, a Recommended Dietary Allowance (RDA) cannot be calculated. for adults is about 250 milligrams per day of combined DHA and EPA (source: Dietary Reference Values for the EU). Fish oils are generally considered safe to take. However, oily fish and fish oils can be contaminated with heavy metals and fat-soluble pollutants, although the benefits of fish intake are usually judged to outweigh the potential risks. Also note that liver-derived fish oil contains vitamin A, which can be harmful in high doses, so there is an upper intake limit of about 3000 micrograms per day in adults (source: Dietary Reference Values for the EU).
For dietary reference values (DRVs) in Europe, consult efsa.europa.eu/drvs/index.htm. Or click here to view all DRVs for vitamins, minerals, and fatty acids (DHA, EPA, and ALA). And, to search for the vitamin/mineral content of specific foods, consult fdc.nal.usda.gov/fdc-app.html.
In younger adults aged 18 to 55, omega-3 supplementation (DHA and EPA) does not seem to improve muscle growth, muscle strength, or blood markers of inflammation and muscle damage beyond what you get from strength training alone. There is currently no meta-analysisA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment. focused on endurance performance.
But…
Omega-3 supplementation (DHA and EPA) does seem to help recovery from hard exercise by reducing self-reported muscle soreness and helping restore range of motion after exercise-induced muscle damage.
In older adults (55 years and older), omega-3 supplementation (DHA and EPA) does not appear to change walking performance or upper-body strength, but it may increase lower-body strength and lower-body functional performance (for example, “get-up-and-go” and “sit-to-stand” tests).
These effects in older adults are seen both with and without resistance training. This suggests that older adults who cannot or do not exercise may still benefit from omega-3 supplementation.
But…
The doses of omega-3 used in different studies vary a lot (EPA from about 300 to 2400 milligrams per day and DHA from about 400 to 1500 milligrams per day). The studies also differ in design and often mix together different supplements (for example, fish oils, DHA, EPA, ALA, and linoleic acid). There is also evidence of publication biasPublication bias in meta-analysis occurs when studies with significant results are more likely to be published than those with non-significant findings, leading to distorted conclusions. This bias can inflate effect sizes and misrepresent the true effectiveness of interventions, making it crucial to identify and correct for it in research., meaning that studies with positive findings are more likely to be published than those with null findings.
It is also unclear whether people in these studies started out with low omega-3 intakes (a diet lacking foods that contain omega-3). If they were deficient, then the supplement would basically just be replacing what was missing, rather than giving a “bonus” effect on top of an already good diet.
More high-quality randomised controlled trialsThe “gold standard” approach for determining whether a treatment has a causal effect on an outcome of interest. In such a study, a sample of people representing the population of interest is randomised to receive the treatment or a no-treatment placebo (control), and the outcome of interest is measured before and after exposure to the treatment and control. are needed, and dose–response relationships still need to be clarified.
If you choose to use omega-3s (DHA and EPA) or fish oils, a reasonable dose is:
About 250 milligrams per day of combined EPA and DHA. A 1 gram (or 1000 milligram) fish oil capsule typically contains around 300 milligrams of combined EPA and DHA. Always check the nutrition label of your fish oil supplement. Note: this is based on the estimated adequate requirement for dietary intake (source: Dietary Reference Values for the EU). The most effective dose for recovery and performance has not yet been clearly defined by research.
This is roughly equivalent to 2 portions of cooked salmon (about 100 grams each) per week (source: fdc.nal.usda.gov/fdc-app.html) or about 1 to 2 grams of dried chia seeds per day (source: fdc.nal.usda.gov/fdc-app.html)
If you are vegetarian or vegan and do not eat fish, you can still get DHA and EPA by using an algae-based omega-3 supplement. These products are made from microalgae (the original source of DHA and EPA in the food chain) and are suitable for people who avoid animal products. As with fish oils, check the label for the actual amount of DHA and EPA per capsule and aim for a combined daily intake of around 250 milligrams.
Taking more doesn’t necessarily mean a bigger effect and dietary supplements like omega-3s and fish oils are intended as a supplement to, not a replacement for, real food.
Can omega-3 and fish oil enhance athletic performance?
A daily omega-3 or fish oil supplement is unlikely to improve performance in most people, unless they are older (55 years or more) and/or have low intakes of DHA or EPA.
In older adults, a daily omega-3 or fish oil supplement is likely to improve lean mass and muscle strength, particularly in the lower body. These effects have not been seen in younger adults.
A daily omega-3 or fish oil supplement is also likely to help reduce feelings of muscle soreness and restore range of motion after muscle-damaging exercise. BUT remember: trying to strongly blunt soreness and inflammation after exercise may also blunt the very processes that drive training adaptations — read more about that at veohtu.com/NSAIDs.
The effect sizeAn effect size is a standardized measure of the magnitude of an effect of an intervention. Unlike p-values, effect sizes show how large the effect is and indicate how meaningful it might be. Common effect size measures include standardised mean difference (SMD), Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. is trivial-to-small for the benefits to lean mass and muscle strength in older adults, and small-to-moderate for the benefits to muscle soreness and range of motion after muscle-damaging exercise.
These effects appear to be similar between trained athletes and untrained folks, and between males and females.
Keep in mind: there is high heterogeneityHeterogeneity shows how much the results in different studies in a meta-analysis vary from each other. It is measured as the percentage of variation (the I2 value). A rule of thumb: if I2 is roughly 25%, that indicates low heterogeneity (good), 50% is moderate, and 75% indicates high heterogeneity (bad). High heterogeneity means there’s more variability in effects between studies and, therefore, a less precise overall effect estimate. (variability) in study designs and effect sizes between studies, a high risk of biasRisk of bias in a meta-analysis refers to the potential for systematic errors in the studies included in the analysis. Such errors can lead to misleading/invalid results, and unreliable conclusions. This can arise because of issues with the way participants are selected (randomisation), how data is collected and analysed, and how the results are reported., and possible publication biasPublication bias in meta-analysis occurs when studies with significant results are more likely to be published than those with non-significant findings, leading to distorted conclusions. This bias can inflate effect sizes and misrepresent the true effectiveness of interventions, making it crucial to identify and correct for it in research.. So, the overall certainty of evidenceCertainty of evidence tells us how confident we are that the results reflect the true effect. It’s based on factors like study design, risk of bias, consistency, directness, and precision. Low certainty means more doubt and less confidence, and that future studies could easily change the conclusions. High certainty means that the current evidence is so strong and consistent that future studies are unlikely to change conclusions. is lowA low quality of evidence means that, in general, studies in this field have several limitations. This could be due to inconsistency in effects between studies, a large range of effect sizes between studies, and/or a high risk of bias (caused by inappropriate controls, a small number of studies, small numbers of participants, poor/absent randomisation processes, missing data, inappropriate methods/statistics). When the quality of evidence is low, there is more doubt and less confidence in the overall effect of an intervention, and new studies could easily change overall conclusions. The most effective way to enhance the quality of evidence is for scientists to conduct large, well-controlled, high-quality randomised controlled trials.. Therefore, additional high-quality randomised controlled trialsThe “gold standard” approach for determining whether a treatment has a causal effect on an outcome of interest. In such a study, a sample of people representing the population of interest is randomised to receive the treatment or a no-treatment placebo (control), and the outcome of interest is measured before and after exposure to the treatment and control. are needed to increase the certainty (confidence) in the overall effect sizes reported in meta-analysesA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment..
The nice part: omega-3s and fish oils do not appear to have a detrimental effect on recovery or performance. So, if you like them and believe they work for you, give em a whirl. But, remember that time and money spent trying to improve your performance or recovery with something that has no obvious benefit might be better spent optimising your training load, sleep habits, and dietary/nutritional choices.
If your usual diet is low in foods containing DHA, EPA, or ALA (for example, oily fish, seeds, and nuts), then an omega-3 or fish oil supplement could be sensible, ideally with advice from your doctor or a dietitian. As with any supplement, “more” does not equal “better”, and a supplement is meant to sit on top of a healthy eating pattern, not replace it — learn how to establish a healthy eating pattern at veohtu.com/healthyeatingpattern.
To minimise the risk of consuming a supplement that contains prohibited substances, only choose products that have been independently tested (e.g., Informed Sport). And, remember: Supplements do not make athletes and do not replace training; they're just the icing on a very well-baked cake. Before reaching for pills and potions, optimise your training load and dial in your sleep, nutrition, and rest.
How to use this: Start by checking your diet. If you already eat oily fish or omega-3-rich seeds and nuts several times per week, you probably do not need a fish oil supplement for performance. If you are older or rarely eat these foods, a daily dose that provides about 250 milligrams of combined EPA and DHA may help with general health and recovery, especially if tough sessions leave you very sore. Choose a batch-tested product, stay within safe vitamin A limits if you use liver-derived oils, and remember that the biggest wins for your performance still come from smart training, good sleep, and consistent fuelling.
Strengthen the fight for clean sport
Remember: You are the only person responsible for what goes in your body! Ignorance is not an excuse! Stay educated. Be informed.
Consult WADA’s prohibited list, cross-check your meds against the Global DRO drug reference list, and only choose supplements that have been tested by an independent body (e.g., Informed Sport or LabDoor).
Information you can trust. All content on Veohtu is meticulously researched and written by Thomas Solomon, PhD. He does not sell supplements, recovery products, or ad space, and he has no sponsorships, brand affiliations, or ambassador roles. Everything you read reflects his independent views, shaped solely by peer-reviewed scientific evidence — and that will never change.
Full list of meta-analyses examining omega-3 and fish oil for performance.
Here are the meta-analyses I've summarised above:
Examining the Influence of Omega-3 Fatty Acids on Performance, Recovery, and Injury Management for Health Optimization: A Systematic Review Focused on Military Service Members. Rittenhouse et al. (2025) Nutrients.
Omega-3 Fatty Acid Supplementation on Post-Exercise Inflammation, Muscle Damage, Oxidative Response, and Sports Performance in Physically Healthy Adults-A Systematic Review of Randomized Controlled Trials. Fernández-Lázaro et al. (2024) Nutrients
Effects of Omega-3 fatty acids supplementation and resistance training on skeletal muscle. Uchida et al. (2024) Clin Nutr ESPEN
Effects of Omega-3 Fatty Acid Supplementation on Skeletal Muscle Mass and Strength in Adults: A Systematic Review. Moon et al. (2023) Clin Nutr Res
Effects of Omega-3 Supplementation Alone and Combined with Resistance Exercise on Skeletal Muscle in Older Adults: A Systematic Review and Meta-Analysis. Stephen M Cornish Dean M Cordingley, Keely A Shaw, Scott C Forbes, Taylor Leonhardt, Ainsley Bristol, Darren G Candow, Philip D Chilibeck. Nutrients (2022)
The effect of long chain omega-3 polyunsaturated fatty acids on muscle mass and function in sarcopenia: A scoping systematic review and meta-analysis. Julia K Bird, Barbara Troesch, Ines Warnke, Philip C Calder. Clin Nutr ESPEN (2021)
Effect of omega-3 fatty acids supplementation on indirect blood markers of exercise-induced muscle damage: Systematic review and meta-analysis of randomized controlled trials. Gao Xin, Hesam Eshaghi. Food Sci Nutr (2021)
N-3 PUFA as an ergogenic supplement modulating muscle hypertrophy and strength: a systematic review. López-Seoane J, Martinez-Ferran M, Romero-Morales C, Pareja-Galeano H. Crit Rev Food Sci Nutr (2021).
The effect of fish oil supplementation on the promotion and preservation of lean body mass, strength, and recovery from physiological stress in young, healthy adults: a systematic review. Heileson JL, Funderburk LK. Nutr Rev (2020).
Are There Benefits from the Use of Fish Oil Supplements in Athletes? A Systematic Review. Lewis NA, Daniels D, Calder PC, Castell LM, Pedlar CR. Adv Nutr (2020).
Omega-3 Polyunsaturated Fatty Acid Supplementation for Reducing Muscle Soreness after Eccentric Exercise: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Zheng-Tao Lv, Jin-Ming Zhang, Wen-Tao Zh. Biomed Res Int (2020)
Response to exercise in older adults who take supplements of antioxidants and/or omega-3 polyunsaturated fatty acids: A systematic review. Rosario Pastor, Josep A Tur. Biochem Pharmacol (2020)
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Who is Thomas Solomon?
My knowledge has been honed following 20+ years of running, cycling, hiking, cross-country skiing, lifting, and climbing, 15+ years of academic research at world-leading universities and hospitals, and 10+ years advising and coaching in athletic performance and lifestyle change.
I have a BSc in Biochemistry, a PhD in Exercise Science, and over 90 peer-reviewed publications in medical journals.
I'm also an ACSM-certified Exercise Physiologist (ACSM-EP), an ACSM-certified Personal Trainer (ACSM-CPT), a VDOT-certified Distance Running Coach, and a UKVRN Registered Nutritionist (RNutr).
Since 2002, I’ve conducted biomedical research in exercise and nutrition and have taught and led university courses in exercise physiology, nutrition, biochemistry, and molecular medicine.
And, with my personal experience of competing on the track (800m to 10,000m), the road (5 k to marathon), on the trails, and in the mountains, by foot, bicycle, cross-country ski, and during obstacle course races (OCR), I deeply understand what it's like to train and compete — I've been there, done it, and gotten sweat, mud, and tears on my t-shirt.
Disclaimer: I occasionally mention brands and products, but it is important to know that I don't sell recovery products, supplements, or ad space, and I'm not affiliated with / sponsored by / an ambassador for / receiving advertisement royalties from any brands. I have conducted biomedical research for which I’ve received research money from publicly-funded national research councils and medical charities, and also from private companies, including Novo Nordisk Foundation, AstraZeneca, Amylin, the A.P. Møller Foundation, and the Augustinus Foundation. I’ve also consulted for Boost Treadmills and Gu Energy on R&D grant applications, and I provide research and scientific writing services for Examine.com. Some of my articles contain links to information provided by Examine.com but I do not receive any royalties or bonuses from those links. Importantly, none of the companies described above have had any control over the research design, data analysis, or publication outcomes of my work. I research and write my content using state-of-the-art, consensus, peer reviewed, and published scientific evidence combined with my empirical evidence observed in practice and feedback from athletes. My advice is, and always will be, based on my own views and opinions shaped by the scientific evidence available. The information I provide is not medical advice. Before making any changes to your habits of daily living based on any information I provide, always ensure it is safe for you to do so and consult your doctor if you are unsure.