Does fish oil help build muscle? The definitive guide to omega-3s and muscle growth

October 4, 2025 •

4 min read

Omega-3 fatty acids, like those found in fish oil, have been shown to augment muscle protein synthesis and reduce inflammation, prompting many to question: does fish oil help build muscle? While not a direct muscle builder like protein, its unique benefits for muscle health and recovery make it a valuable tool for any fitness enthusiast.

Quick Summary

Fish oil's omega-3s aid muscle growth by reducing post-exercise inflammation, enhancing protein synthesis signals, and maintaining muscle mass during dieting or aging. These benefits support faster recovery and better performance, complementing traditional muscle-building strategies.

Key Points

Enhances Protein Synthesis: Omega-3s, particularly EPA and DHA, activate the mTOR pathway, which is crucial for stimulating lean muscle growth.
Reduces Muscle Soreness: By leveraging their anti-inflammatory properties, fish oil helps mitigate delayed onset muscle soreness (DOMS) after intense workouts.
Supports Recovery: Reduced inflammation allows for faster tissue repair and shorter recovery times, enabling more consistent training.
Preserves Muscle Mass: Fish oil may help preserve muscle mass during periods of caloric deficit or inactivity, which is critical during a cutting phase.
Optimal Intake is Key: For maximum benefit, consider an intake of combined EPA and DHA that aligns with recommendations for bodybuilders and athletes.
Complementary Supplement: Fish oil is a supportive supplement that optimizes muscle-building conditions, complementing primary anabolic agents like protein.

Understanding the Omega-3s in Fish Oil

Fish oil is a rich source of two potent omega-3 polyunsaturated fatty acids (PUFAs): eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Unlike alpha-linolenic acid (ALA) found in plants, which the body must inefficiently convert, EPA and DHA are readily used by the body for various functions, including supporting the cellular membrane. For bodybuilders, these fatty acids are prized for their anti-inflammatory properties, which can significantly impact the muscle-building and recovery process.

The Direct Influence on Muscle Protein Synthesis

Muscle growth, or hypertrophy, relies on muscle protein synthesis (MPS) exceeding muscle protein breakdown. Research indicates that omega-3s, particularly EPA and DHA, play a crucial role in regulating this process.

Activation of the mTOR Pathway: A key pathway for muscle growth is the mammalian target of rapamycin (mTOR) signaling. Studies have shown that omega-3 supplementation can increase the phosphorylation of mTOR, stimulating lean muscle growth. This effect helps prime muscle tissue to respond more robustly to insulin and amino acids after a workout.
Enhanced Anabolic Response: By increasing the muscle's sensitivity to amino acids, omega-3s help optimize the body's use of dietary protein for muscle repair and growth. This is particularly beneficial for older adults, who experience anabolic resistance and require a greater stimulus for MPS.

The Role of Inflammation and Muscle Recovery

Intense resistance training creates microscopic tears in muscle fibers, triggering an inflammatory response that leads to delayed onset muscle soreness (DOMS). While a normal part of the process, excessive inflammation can hinder recovery and impede muscle growth.

Anti-inflammatory Effects: The EPA in fish oil is particularly effective at reducing post-workout inflammation. It is converted into anti-inflammatory compounds called resolvins, which help to "turn off" the inflammatory response, allowing faster tissue repair.
Reduced Muscle Soreness: Several studies have demonstrated that fish oil supplementation can significantly reduce the severity of DOMS, leading to less perceived pain and stiffness. This can help athletes maintain consistency in their training, as reduced soreness allows for more frequent and effective workouts.
Improved Range of Motion: By mitigating inflammation and damage, fish oil can help preserve a greater range of motion following intense exercise.

Supporting Muscle Health During Caloric Deficits

Bodybuilders often go through "cutting" phases, where they restrict calories to lose body fat. This process carries the risk of losing hard-earned muscle mass. Omega-3s can offer a protective effect during this time.

Preserving Lean Mass: In studies on individuals following a low-calorie diet, supplementing with fish oil has been shown to maintain or even increase lower-body muscle strength, helping to preserve muscle mass.
Potential for Fat Loss: Some research suggests omega-3s may increase metabolic rate and aid in body fat reduction, potentially by improving insulin sensitivity and nutrient partitioning. This helps direct nutrients towards muscle cells rather than fat stores.

Fish Oil vs. Other Muscle-Building Supplements

It is important to understand how fish oil complements, rather than replaces, other popular supplements in a muscle-building stack. This table provides a quick comparison.


Feature	Fish Oil (Omega-3s)	Whey Protein	Creatine Monohydrate
Primary Role	Indirectly aids muscle growth by reducing inflammation and enhancing nutrient sensitivity.	Directly provides amino acids for muscle repair and synthesis.	Increases ATP (energy) availability for more powerful, explosive lifts.
Mechanism	Modulates inflammation, activates mTOR signaling, and improves cell membrane function.	Supplies readily-available amino acids (especially BCAAs) to stimulate MPS.	Replenishes phosphocreatine stores in muscles, improving performance.
Best for	Enhancing recovery, reducing soreness, and supporting muscle health long-term.	Post-workout muscle repair and stimulating MPS with high-quality protein.	Boosting strength and power output during intense, short-duration exercise.
Optimal Timing	With a meal, ideally post-workout, for better absorption.	Immediately post-workout to kickstart MPS.	Can be taken at any time, but often paired with a post-workout shake.

Finding Quality Fish Oil

When choosing a supplement, consider the following:

Read the Label: The 'per serving' amount listed on a fish oil bottle can be misleading. Check the concentration of active EPA and DHA.
Aim for a High Concentration: Higher quality fish oil products contain higher levels of EPA and DHA per capsule or teaspoon.
Consider Sustainable Sources: Look for supplements that source from wild-caught, fatty fish and provide test results for purity, confirming low levels of heavy metals and other contaminants.
Algae-Based Alternatives: For vegetarians, vegans, or those with a fish allergy, algae-based omega-3 supplements are an excellent alternative as they provide direct EPA and DHA.

Conclusion: A valuable tool for a balanced approach

So, does fish oil help build muscle? In summary, fish oil is not a direct anabolic agent for building new muscle tissue in the way that protein is. However, it plays a vital supportive role by enhancing the body's natural muscle-building processes, primarily through its potent anti-inflammatory effects and ability to enhance protein synthesis signaling. By reducing inflammation and soreness, it facilitates faster recovery, enabling more consistent and intense training sessions. This, combined with its potential benefits for preserving muscle mass during caloric restriction, makes fish oil a valuable component of a comprehensive bodybuilding nutrition strategy. The key is to combine it with adequate protein intake and a well-structured resistance training program to realize its full potential.

Authoritative Source:

The Influence of Omega-3 Fatty Acids on Skeletal Muscle Protein Synthesis and Muscle Mass

Frequently Asked Questions

For optimal muscle-building and recovery benefits, an intake of combined EPA and DHA that aligns with recommendations for bodybuilders is generally suggested. Always check the supplement label for the actual EPA and DHA content and consult with a healthcare professional.

Fish oil and whey protein serve different functions. Whey protein provides the amino acid building blocks for muscle repair, while fish oil reduces inflammation and enhances the body's protein synthesis signals. For best results, use them both.

Yes, fish oil can help reduce delayed onset muscle soreness (DOMS). Its omega-3s, especially EPA, help control the inflammatory response that causes muscle tenderness and stiffness after intense exercise.

There is no single best time, but many experts recommend taking it with a meal, preferably post-workout, to aid absorption. Taking it consistently is more important than the specific timing.

It is possible to get omega-3s from dietary sources like fatty fish (salmon, sardines) and some plants (walnuts, flaxseed). However, bodybuilders often find it challenging to consume high enough concentrations of active EPA and DHA from diet alone, making supplementation a practical option.

Common side effects are usually mild and can include a fishy aftertaste, belching, indigestion, or diarrhea. Serious side effects are rare but can include increased bleeding risk, especially at high intakes or with certain medications.

Yes, fish oil has shown potential in mitigating sarcopenia, the age-related loss of muscle mass. Its anti-inflammatory properties and ability to enhance muscles' sensitivity to protein can help maintain muscle mass and strength in older adults.