Omega 3 for muscle growth has attracted increasing interest in sports nutrition. Research suggests EPA and DHA may influence muscle health, strength and exercise recovery, but the evidence is more nuanced than simply saying fish oil builds muscle.
🕒 7 min read
Can omega 3 help muscle growth?
Omega 3 may support some aspects of muscle health and adaptation to exercise, but taking an omega-3 supplement does not by itself build muscle. Resistance training, sufficient energy and adequate dietary protein remain the foundations of increasing muscle mass.
Research into the long-chain omega-3 fatty acids EPA and DHA has investigated muscle protein synthesis, strength and recovery. Some studies have reported benefits, particularly in older adults, but results differ depending on age, sex, training status, dose and study design.34
Importantly, there is currently no authorised Great Britain health claim stating that omega 3 increases muscle growth or muscle mass. EPA and DHA do have authorised nutritional claims relating to normal heart function, while DHA has authorised claims relating to normal brain function and vision when the relevant conditions of use are met.1
What does the latest research say about omega 3 and muscle?
The overall picture is promising in some areas but mixed. A 2025 position stand from the International Society of Sports Nutrition concluded that omega-3 supplementation may not provide a muscle-hypertrophy benefit in young adults, although supplementation alongside resistance training may improve strength depending on dose and duration. It also concluded that omega 3 may reduce subjective muscle soreness after intense exercise.3
| Area | What the evidence suggests | What this means in practice |
|---|---|---|
| Muscle growth | Some studies, particularly in older adults, suggest potential effects on muscle protein metabolism and muscle mass, but results are not consistent across populations. | Omega 3 should not be viewed as a replacement for resistance training, sufficient calories or dietary protein. |
| Strength | Omega-3 supplementation alongside resistance training may improve strength in some circumstances, although findings vary between studies. | Any effect is likely to be additional to, rather than a substitute for, an effective training programme. |
| Exercise recovery | Recent reviews suggest long-chain omega 3 may reduce some measures of exercise-induced muscle soreness and muscle damage. | Omega 3 may have a role within a wider recovery strategy that also includes rest, hydration and appropriate nutrition. |
| Weight loss | Evidence does not consistently show that omega-3 supplements increase weight or fat loss. | Omega 3 should not be promoted or used as a weight-loss supplement. |
Omega 3 and muscle protein synthesis
One reason omega 3 has attracted interest in muscle research is its potential effect on muscle protein synthesis – the process through which the body builds and repairs muscle proteins.
Earlier controlled studies in older adults found that omega-3 supplementation could increase the muscle protein synthesis response to amino acids and insulin. More recent reviews have found potentially beneficial effects on muscle health, but the studies vary considerably in their participants, supplementation protocols and outcomes.4
This means it is too strong to say that omega 3 will increase muscle mass in everybody. Current sports-nutrition guidance is particularly cautious about claiming a hypertrophic effect in healthy younger adults.3
Omega 3, ageing and muscle
Maintaining muscle becomes increasingly important with age because older adults can experience a gradual reduction in muscle mass and strength.
Omega-3 research in older populations is of particular interest because some trials have reported improvements in muscle-related outcomes. However, omega-3 supplements should not be described as preventing or treating sarcopenia. Resistance exercise and adequate nutrition remain central to maintaining muscle as we age.4
Can omega 3 help muscle recovery and DOMS?
There is growing evidence that long-chain omega-3 supplementation may influence some aspects of recovery after strenuous or unfamiliar exercise.
A 2026 systematic review and meta-analysis of research in healthy young and middle-aged adults found that omega-3 supplementation reduced delayed-onset muscle soreness (DOMS), creatine kinase and muscle swelling after eccentric exercise, while some measures of strength and range of motion also improved. However, the authors highlighted substantial differences between studies and said the evidence was not sufficient to establish an effective dose or supplementation duration.5
A separate 2026 analysis of trained athletes also found omega-3 supplementation showed potential benefits for recovery outcomes, although creatine had stronger evidence for strength and protein performed better for endurance within that analysis.6
So while omega 3 may form part of an athlete's overall nutrition strategy, adequate sleep, hydration, carbohydrate and protein intake, and appropriate training load remain important for recovery.
For more on post-workout nutrition, read our guide to muscle recovery supplements.
Does omega 3 help with weight loss or body fat?
Current evidence does not support omega-3 supplements as a reliable weight-loss aid.
Earlier individual studies suggested fish oil combined with exercise might influence body composition, which is why omega 3 was sometimes promoted in relation to becoming leaner. However, the wider evidence is inconsistent.
A 2025 systematic review and meta-analysis of randomised controlled trials in adults with overweight or obesity found that adding long-chain omega 3 during calorie restriction did not significantly improve reductions in fat mass or preserve fat-free mass compared with control interventions.7
For anyone aiming to become leaner while maintaining muscle, total energy intake, sufficient protein and resistance training are much more important factors.
What is omega 3 and where can you get it?
The three main types of omega-3 fatty acids are alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
ALA is an essential fatty acid found in foods such as flaxseed, chia seeds, walnuts and rapeseed oil. The body can convert ALA into EPA and DHA, but this conversion is limited.
EPA and DHA are long-chain omega-3 fatty acids found primarily in oily fish and marine algae. Oily fish such as salmon, sardines, herring, mackerel and trout are useful dietary sources.
The NHS recommends eating at least two portions of fish each week, including one portion of oily fish.2
People who do not eat fish can obtain ALA from plant foods, while algae-derived supplements provide a direct vegetarian and vegan source of EPA and DHA.
For more detail, see what EPA and DHA are and why you need both.
How much omega 3 do active people need?
There is no single omega-3 supplement amount that is appropriate for every active person. UK public-health guidance focuses primarily on eating fish regularly rather than recommending a specific sports-supplement dose.
Sports-nutrition research has used a wide range of EPA and DHA amounts and supplementation periods, which makes it difficult to identify one optimal intake for muscle growth or recovery.35
If you are choosing a supplement, look at the amount of EPA and DHA in the recommended serving rather than just the total amount of fish oil. Our guide to what to look for in an omega-3 supplement explains how to compare products.
You can also browse Healthspan's full omega-3 supplements range.
When is the best time to take omega 3?
Research has not established a particular time of day as necessary for gaining potential exercise-related benefits from omega 3. Consistency is more relevant than whether a supplement is taken before or after training.
Follow the directions on the individual product. If you find fish oil causes digestive discomfort or an unpleasant aftertaste, taking it with food may be more comfortable.
Omega-3 supplement safety
Always follow the directions for the individual supplement and do not exceed its recommended daily intake. Food supplements should not be used as a substitute for a varied, balanced diet and healthy lifestyle.
If you take prescribed medication, have a medical condition, are pregnant or breastfeeding, speak to a doctor, pharmacist or other appropriate healthcare professional before taking a supplement.
