Have you been training, eating right, but something feels off? Perhaps adaptations aren’t what you expect, or maybe you just don’t feel good. Well, new research shows the problem might be your gut.
Specifically known as your gut-muscle axis, emerging research shows that a strong line of communication exists between your gut and skeletal muscle. Communication between the two can actually affect things like muscle mass, strength, recovery, and even metabolic function.
This is why gut health has become a very important consideration in health, wellness, and even adding mass. This article will tell you what you need to know about the gut-muscle axis.
Key Points You Need To Know!
The Gut-Muscle axis refers to crosstalk between your muscle mass and digestive system.
Your gut and skeletal system can both affect each other, making it important to focus on both.
Feelings of fatigue, low energy, and sub-optimal performance or adaptations in the gym could possibly be linked to poor gut health.
Increased activity and training can naturally increase the biodiversity of your gut.
What Is the Gut–Muscle Axis?
The Gut-Muscle axis refers to the bidirectional crosstalk that takes place between your skeletal muscle system and gastrointestinal system. Crosstalk between the two occurs through various compounds, such as;
Metabolites
Myokines (interleukin-6)
Cytokines
Various signaling molecules (Chew et al., 2023).
Usually thought of as two distinct systems, research shows these two organs actually have a significant influence on one another.
What Are Examples Of Muscle-Gut Axis Cross Talk?
The muscle-gut axis goes both ways, so improving both is essential. Here are some ways they can influence one another.
Gut → Muscle (How The Microbiome Influences Skeletal Muscle)
Fermentation of fiber creates Short-Chain Fatty Acids (SCFAs), which improve insulin sensitivity, enhance mitochondrial function, and reduce systemic inflammation.
Gut permeability (“leaky gut”) increases inflammatory compounds that can impair anabolic signaling and increase muscle breakdown.
Amino Acid Availability is dependent on your gut’s ability to digest and absorb protein.
Muscle → Gut (How Skeletal Muscle Influences The Microbiome)
Contracting Muscles Release Myokines, which can influence gut barrier integrity and microbial composition.
Physical Activity and Training Improves Gut Health, with athletes showing greater microbial diversity.
Lactate Fuels “Good Bacteria”: Exercise increases circulating lactate, which is metabolized by certain “good” bacteria (lactate-utilizing bacteria (LUB))
Exercise Regulates Stress Hormones, which influence gut permeability and microbial balance (Jäger et al., 2019; Mohr et al., 2020).
Why Is Your Gut Important for Building Muscle?
Key Points You Need To Know!
Gut byproducts (SCFAs) can stimulate muscle protein synthesis (MPS) and increase nutrient absorption.
SCFAs may enhance endurance and promote muscle growth by triggering AMPK and improving mitochondrial function.
A healthy gut may help reverse and resist anabolic resistance.
A healthy, intact intestinal barrier prevents harmful bacteria from entering the bloodstream, mitigating systemic inflammation and even muscle atrophy.
Muscle growth occurs through lifting weights and eating enough protein in a caloric surplus. However, optimization of hypertrophy assumes your body is actually absorbing the protein and nutrients.
Containing trillions of microbes, this is just one of your gut’s functions that can actually affect hypertrophy and strength (Jäger et al., 2019; Barry et al., 2025).
How Does A Healthy Gut Improve Muscle Mass And Training?
1. Short-Chain Fatty Acids (SCFAs) and Muscle Mass
Short-chain fatty acids (SCFAs) are one of the primary factors and most important players in gut health; this means they’re also crucial for muscle mass.
These fatty acids are produced when gut bacteria ferment dietary fiber and primarily consist of;
Butyrate
Acetate
Propionate
Why does this matter for hypertrophy?
The exact relationship is still being researched, but there is a clear relationship between SCFA production and muscle health.
Influences Muscle Mass and Strength. Low amounts of SFCA are associated with lower muscle mass and strength (Barry et al., 2025; Lustgarten, 2019).
Muscle Preservation and Atrophy. SCFA can influence muscle preservation and mitigate atrophy (Walsh et al., 2015)
Muscle Protein Synthesis (mTOR Activation): SCFAs stimulate mTOR, which is essential for increasing muscle protein synthesis and promoting hypertrophy (Jäger et al., 2019).
Reduced Inflammation and Prevents Muscle Atrophy: SCFAs inhibit specific inflammatory compounds that contribute to muscle atrophy (Xu & He, 2025)
Insulin Sensitivity: SCFAs improve glucose uptake and metabolism in skeletal muscle, providing better fuel for muscle maintenance.
2. Enhanced Protein Absorption and Muscle Protein Synthesis
For hypertrophy, total daily protein intake is non-negotiable. However, intake alone does not guarantee optimal utilization. This depends on;
Digestion
Absorption
Metabolic response
All of this determines whether your protein shake actually stimulates muscle protein synthesis.
Why does this matter for hypertrophy?
The International Society of Sports Nutrition Position Stand on Probiotics (Jäger et al., 2019) states probiotics can;
Enhance digestive efficiency and improve amino acid absorption.
Improve the leucine threshold response
Produce proteolytic enzymes that assist in breaking down dietary protein into absorbable peptides and amino acids.
Reduce gastrointestinal distress and nutrient absorption during high-protein phases.
3. A Healthy Gut Mitigates Inflammation and Can Help You Recover Faster
Training at the gym or track places stress on the muscles that trigger various responses, such as inflammation and muscle breakdown.
These play a central role in building muscle but are only beneficial if we can recover from them. This is governed through;
Inflammatory control
Oxidative stress management
Immune function
Nutrient delivery
Why does this matter for lifters?
Excessive inflammation can overwhelm the anabolic process and blunt recovery and adaptations. (Mohr et al., 2020; Jäger et al., 2019).
Therefore, improving your gut’s health is crucial for controlling systemic stress, helping you recover faster, improving adaptations, and increasing performance.
Emerging research shows that a healthier gut environment may:
Reduce Excessive Post-exercise Inflammation. The composition of your gut’s microbiota influences inflammation, oxidative stress, and recovery markers following strenuous exercise (Mohr et al., 2020)
Reduce Muscle Damage and Improve Recovery. Probiotics have been found to decrease exercise-induced muscle damage and improve recovery in strength training (Jäger et al., 2016).
Improves Antioxidant Capacity. Probiotic supplementation has shown to reduce markers of muscle damage and improve antioxidant status after prolonged endurance events. (Fu et al., 2021).
Support Immune Resilience During High-Volume Training. Allow higher-quality sessions with better recovery between them.
4. Energy, Nutrient, and Lean Mass Accrual
Similar to protein metabolism, the calories and nutrients you eat require proper absorption to be utilized.
For someone in a surplus, this raises an important question: Where do those calories go, and how are nutrients processed?
This is influenced by the gut microbiome, and different microbial profiles are associated with differences in energy substrate metabolism (Turnbaugh et al., 2006).
What This Means For Lifters
In practical terms, a healthy and resilient gut with higher levels of SCFA is more efficient at digesting and absorbing nutrients for utilization (Frost et al., 2014; Chew et al., 2023).
Long-term, this can help support lean mass accrual during a surplus. Other benefits include;
Energy Regulation: A healthy gut microbiome helps regulate pulling energy from food. An imbalanced gut (dysbiosis) is often associated with higher fat storage.
Improves Hormonal Balance: Gut health influences key anabolic hormones like insulin, which is crucial for nutrient uptake into muscle cells.
Improved Body Composition: Specific gut bacteria can enhance fatty acid oxidation and prevent excessive fat accumulation in peripheral organs.
Regulate Glucose Metabolism and Insulin Sensitivity: Optimizing the availability of energy substrates for muscle contraction and repair.
How Can I Fix My Gut?
Key Points You Need To Know!
Maintaining a healthy gut requires a systematic strategy and building a strong foundation.
Probiotics and prebiotics are foundational tools in improving gut health and flora
Vitamin A & D and L-Glutamine play central roles in repairing the gut’s lining and are often used for therapy
Colostrum powder is proving to be a strong supplement for gut health and improving immunity.
Increased activity and exercise play a foundational role, with active populations naturally having superior gut health.
Increase Fiber Intake And Prebiotics
Most individuals on a Western Diet consume very low amounts of fiber, the natural source of prebiotics. As such, this population likely suffers from suboptimal gut health and low SFCAs.
1. Fuel “good” bacteria and flora. Prebiotics are the primary energy source for beneficial gut microbes. This helps them grow and outcompete harmful bacteria.
2. Producing short-chain fatty acids (SCFAs): When fermented by gut bacteria, prebiotics produce SCFAs, which support gut lining integrity, metabolic health, and inflammation control.
3. Improving digestion and nutrient absorption: By improving microbial balance, prebiotics help regulate bowel function and support more efficient nutrient extraction.
Probiotics and Muscle Growth
Probiotics introduce “good” bacteria into your gut and increase the flora. Not only does this mitigate the growth of “bad” bacteria, but the good bacteria also offer a host of benefits.
1. Reduced Exercise-Induced Muscle Damage: A study by Jäger et al. (2016) found that probiotic supplementation reduced markers of exercise-induced muscle damage and improved recovery in resistance-trained men.
2. Enhanced Protein Absorption: Certain probiotic strains may improve protein absorption in the gut and increase muscle protein synthesis (Jäger et al., 2019).
3. Improved Nutrient Utilization: Probiotics can enhance the utilization of key nutrients involved in muscle growth and recovery, such as amino acids, carbohydrates, and key vitamins (Manach et al., 2019).
We are now carrying a Probiotic + Prebiotic supplement for gut health.
This is called a symbiotic approach, and research suggests it’s the best approach as the compounds feed off each other (literally) and can produce optimal results (Gurry, 2017).
Exercise And Resistance Training
Improved gut health is yet another benefit of exercise and resistance training.
1. Endurance Training Increases Gut Bacteria Diversity. Allen et al. (2018) showed endurance training can alter gut microbiota and increase fecal SCFAs in lean individuals.
2. Resistance Training Enhances Specific Flora. Resistance training can enhance specific beneficial bacteria, which ultimately optimizes the gut–muscle axis (Chew et al., 2023; Xu & He, 2025).
3. Athletes Naturally Have Healthier Guts. Active populations consistently demonstrate greater microbial diversity and optimal gut profiles compared to sedentary individuals (Mohr et al., 2020; Li et al., 2025).
If you need help with a program, research is clear that following a program leads to better results and increased adherence.
SET FOR SET has a host of training programs that will get the job done. For more serious lifters, contact us for a personalized approach to reach your goals.
Vitamin A & D, L-Glutamine, Colostrum Powder
These supplements are proven to play key roles in improving gut health and decreasing permeability.
Vitamin A & D- Vitamin A & D work synergistically to decrease permeability and improve flora (Aggeletopoulou et al., 2023; Cantorna et al., 2019).
L-Glutamine- L-glutamine is the primary fuel source for enterocytes (intestinal lining cells) and promotes cell growth.(Perna et al., 2019).
Colostrum Powder- Provides nutrients needed to repair the lining of the gut and reduce inflammation. It also acts as a prebiotic and fuels healthy bacteria (Chandwe & Kelly, 2021)
Practical Strategies to Support Your Gut–Muscle Axis
1. Consume adequate dietary fiber (25–40g/day): Fiber fuels SCFA production.
2. Include fermented foods regularly. Yogurt, kefir, kimchi, sauerkraut.
3. Train consistently. Both resistance and aerobic training support microbial diversity.
4. Avoid chronic NSAID overuse. NSAIDs can impair gut barrier integrity.
5. Diversify protein sources. Mixed protein intake may support microbial diversity.
6. Manage excessive stress and sleep debt. Chronic stress disrupts microbial balance.
7. Supplement with prebiotics and probiotics. Where appropriate, this can help optimize the function of your gut.
FAQ: Gut–Muscle Axis: How Your Microbiome Influences Muscle Growth, Strength, and Recovery
1. What Is The Gut–Muscle Axis?
The gut–muscle axis refers to crosstalk between your gut microbiome and skeletal muscle. Gut bacteria influence muscle through inflammatory control, insulin sensitivity, and short-chain fatty acid (SCFA) production, while exercise alters gut diversity through myokines, lactate signaling, and improved metabolic regulation.
2. How Does The Microbiome Affect Muscle Growth?
Certain gut bacteria produce short-chain fatty acids (SCFA) that improve insulin sensitivity and reduce systemic inflammation. It also improves amino acid availability and nutrient absorption, indirectly supporting hypertrophy.
3. Can Gut Health Impact Strength And Performance?
Yes. Microbial diversity is associated with improved mitochondrial efficiency, better energy metabolism, and lower inflammatory load. Long-term, these factors can lead to improved force production, endurance capacity, and recovery between training sessions.
4. Does Exercise Improve Gut Health?
Regular resistance training and aerobic exercise increase microbial diversity and promote beneficial bacterial species. Exercise also releases myokines that influence gut barrier integrity and inflammatory regulation.
References
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