GLP-1s and Muscle Loss: Can Gut Health Make a Difference?

Losing weight can feel empowering until you realise you are losing muscle too. Especially in midlife, preserving muscle is essential for strength, metabolism, and health.

Let’s explore why GLP-1 medications like Wegovy® and Ozempic® may lead to muscle loss, why preserving muscle matters, and how gut support can help protect your strength during weight loss.

Why Weight Loss Can Lead to Muscle Loss

Losing weight is often seen as a win. But your body may shed muscle along with fat and that is something we want to avoid. Muscle is essential for:

• Keeping your metabolism active.
• Supporting blood sugar control.
• Maintaining mobility, balance, and strength as you age. [1]

But here is the catch: whether you are losing weight through calorie restriction, exercise, surgery, or GLP-1 medications like Wegovy® or Ozempic®, muscle loss is a common challenge.

When your body is in a calorie deficit, eating less than it burns, it starts breaking down tissue for energy. This includes:

• Fat (which we want to lose).
• Muscle (which we want to keep!). [2]

Without proper protein intake, resistance training, and support for your metabolism, your body may turn to muscle stores to meet its energy needs.

GLP-1 receptor agonists reduce appetite so effectively that many people:

• Eat far fewer calories than usual.
• Struggle to get enough protein to maintain muscle.
• Experience slowed digestion, which can reduce protein absorption. [3]

Also, not everyone prioritises resistance exercise, which is key to muscle preservation.
Research shows that 15–40% of the total weight lost on GLP-1s may come from muscle rather than fat.  This is not inevitable, but without the right strategies, it is a real challenge. [4]

Why Muscle Preservation Matters in Midlife

As we age, muscle decline (sarcopenia) accelerates:

• Muscle supports metabolism, blood sugar control, and physical resilience.
  
• Muscle loss increases the risk of frailty, falls, and loss of independence [5]

Protecting muscle is not optional. It is essential for your health and happiness.

The Gut–Muscle Connection: Why Your Microbiome Matters

Emerging research shows a powerful link between gut health and muscle: [6]

• A balanced microbiome lowers inflammation and improves protein absorption, aiding muscle maintenance.
  
• Some gut bacteria produce short-chain fatty acids (SCFAs) like butyrate, supporting muscle repair and reducing inflammation.
  
• Animal and pilot human studies suggest probiotic support can enhance muscle strength and function. [7]

Your gut may play a surprising but crucial role in preserving muscle.

Four Smarter Ways to Protect Muscle

1. Boost protein: Aim for 1.0–1.6 g per kg body weight, spread evenly across meals.
2. Do strength training: Resistance exercise twice weekly preserves and builds muscle
   
3. Pace weight loss: Keeping weight loss under 1 kg per week supports muscle retention
   
4. Support gut health: Consume fibre, fermented foods, and a targeted probiotic to enhance digestion, calm inflammation, and boost nutrient absorption

How Forte80™ Supports Strength

Forte80™ delivers 80 billion CFUs of four probiotic strains, designed specifically for people on GLP-1 therapy:

• Enhances digestion: making nutrients like protein more available.
  
• Supports microbial diversity: boosting SCFA production and nutrient utilization.
  
• Reduces gut inflammation: protecting muscle repair and function.

Think of Forte80™ as gut-powered support to help you stay comfortable and on track during your weight loss journey.

Final Thought: Keep Muscle While You Lose Fat

GLP-1s are great and very effective in weight loss, but maintaining strength matters more than ever, especially in midlife. With a combination of protein, strength training, and gut support, you can lose fat and preserve muscle.

1. Wong, R., et al. Sarcopenia and metabolic dysfunction associated steatotic liver disease: Time to address both. World J Hepatol. 2024;16(6):871-877.
   doi:10.4254/wjh.v16.i6.871
   
2. Phillips, S. M., et al. Protein "requirements" beyond the RDA: implications for optimizing health. Appl Physiol Nutr Metab. 2016 May;41(5):565-572. 
   
3. Moiz, A., et al. Mechanisms of GLP-1 receptor agonist-induced weight loss: A review of central and peripheral pathways in appetite and energy regulation. Am J Med. 2025 Jun;138(6):934-940.
   
4. Memel, Z., et al. Impact of GLP-1 receptor agonist therapy in patients high risk for sarcopenia. Curr Nutr Rep. 2025 Apr 28;14(1):63.
   
5. Cruz-Jentoft, A. J., et al. Sarcopenia: revised European consensus on definition and diagnosis. Age Ageing. 2019 Jan;48(1):16-31. 
   
6. Ticinesi, A., et al. Gut microbiota, muscle mass and function in aging: A focus on physical frailty and sarcopenia. Nutrients. 2019 Jul 17;11(7):1633.
   
7. Prokopidis, K., et al. Impact of probiotics on muscle mass, muscle strength and lean mass: a systematic review and meta‐analysis of randomized controlled trials. J Cachexia Sarcopenia Muscle. 2022 Nov 22;14(1):30–44.