GLP-1 Weight Loss Medications and Muscle Loss: What Many People Don’t Realize

GLP-1 medications such as Ozempic®, Wegovy®, and Mounjaro®* have dramatically changed the conversation around weight loss.

For many people struggling with obesity, insulin resistance, or stubborn weight gain, these medications can produce significant and life-changing results.

But there is an important aspect of rapid weight loss that many people may not fully realize:

weight loss does not only involve fat.

In many cases, people also lose a meaningful amount of muscle mass during the process.

At B-Sculpt, we increasingly speak with clients who are using GLP-1 medications and want to better understand how to:

• preserve muscle,

• support metabolism,

• maintain body composition,

• and reduce loose skin concerns during weight loss.

Weight Loss vs. Body Composition

When the number on the scale drops quickly, it can feel exciting and motivating. But from a body composition perspective, the goal is ideally not just losing weight —

it’s preserving as much lean muscle as possible while reducing excess fat.

Research suggests that a significant portion of weight lost during GLP-1 treatment may come from lean body mass, including muscle tissue.^1,3 In the STEP 1 clinical trial published in the New England Journal of Medicine, participants taking semaglutide lost an average of 14.9% of their body weight, and follow-up body composition analyses showed that approximately 39% to 40% of the total weight lost came from lean body mass.^1 Similar findings have also been observed with tirzepatide (Mounjaro®), where clinical trial data suggested that roughly 25% to 30% of weight loss may come from lean mass.^3

This matters because muscle plays a critical role in:

• metabolism

• strength

• mobility

• posture

• recovery

• energy expenditure

• and long-term weight maintenance.

  
  

Losing too much muscle can contribute to:

• weakness

• reduced metabolic rate

• fatigue

• poorer body composition

• and a “smaller but softer” appearance.

For some individuals, rapid weight loss may also contribute to increased loose skin and reduced skin firmness.^6

Why Muscle Loss Happens During Rapid Weight Loss

The body does not exclusively burn fat during weight loss.

When calorie intake drops significantly — especially without adequate resistance training or protein intake — the body may also break down muscle tissue.^4,5

This can be even more pronounced when:

• weight loss occurs rapidly

• physical activity decreases

• protein intake is inadequate

• or resistance training is inconsistent.

As we age, preserving muscle mass becomes even more important because natural age-related muscle loss already occurs over time.

The Importance of Muscle Preservation

Many wellness experts now emphasize that successful weight loss should focus not only on reducing fat, but also on preserving strength and lean tissue.^4

Maintaining muscle mass during weight loss may help support:

• metabolic health

• physical function

• strength

• body contour

• and long-term sustainability.

This is one reason why resistance training and adequate protein intake are often recommended alongside GLP-1 medications.

Can HIFEM Muscle Stimulation Help?

At B-Sculpt, many clients using GLP-1 medications are interested in supporting muscle development and body composition during their weight loss journey. Our HIFEM body sculpting treatments use high-intensity focused electromagnetic technology designed to trigger powerful muscle contractions that intensely stimulate targeted muscles.

These treatments are not a replacement for:

• exercise

• nutrition

• or medical care.

However, they may help complement an active lifestyle by supporting:

• metabolic activation

• core strengthening

• muscle toning

• and body contouring goals.

Many clients appreciate that treatments are non-invasive, painless and require no downtime, making them easier to fit into busy schedules.

The Loose Skin Concern During Rapid Weight Loss

Another common concern during significant weight loss is loose or sagging skin. Skin naturally loses elasticity with age due to changes in:

• collagen

• elastin

• hydration

• and tissue support.

When weight loss occurs quickly, the skin may not always tighten at the same pace.^5

This is especially common around:

• the abdomen

• arms

• thighs

• and lower face.

The risk may increase with:

• larger amounts of weight loss

• aging

• reduced muscle support

• and rapid body changes.

How RF Body Contouring May Help Support Skin Tightening

Radiofrequency (RF) body contouring treatments are commonly used to help support skin tightening by delivering controlled heat into deeper tissue layers. This method aims to boost collagen production and enhance skin firmness gradually. At B-Sculpt, we've observed remarkable outcomes using our Sharplight Rapid Contour device. Noticeable results appear after five weekly sessions, with complete outcomes visible 2-3 months later. The advantage of these treatments is that, as the skin develops a denser collagen matrix, the effects are enduring—they become an integral part of the skin rather than a short-term solution like other alternatives.

At B-Sculpt, many clients combine:

• our muscle-focused HIFEM treatments

with

• our RF skin tightening technology

to support both:

• muscle activation,

• and skin quality during body transformation.

This combined approach helps to improve:

• overall body contour

• skin firmness

• and the appearance of treated areas.

A More Balanced Approach to Weight Loss

GLP-1 medications can be an incredibly valuable tool for many people.

But increasingly, the conversation is shifting beyond:

“How much weight was lost?”

Toward:

“What kind of weight was lost?”

Supporting:

• muscle mass,

• metabolic health

• strength

• recovery

• and skin quality

  
  

since these all play important roles in achieving healthier and more sustainable body composition outcomes.

At B-Sculpt in Montreal, many of our clients are looking for realistic, supportive strategies that complement healthy lifestyle changes and medical weight loss programs. Because long-term wellness is not just about becoming smaller. It’s about staying strong, healthy, and confident throughout the process.

References

1. Wilding JPH, et al. “Once-Weekly Semaglutide in Adults with Overweight or Obesity.” New England Journal of Medicine. February 2021. https://www.nejm.org/doi/full/10.1056/NEJMoa2032183

   
   

2. Rubino D, et al. “Effect of Weekly Subcutaneous Semaglutide vs Placebo as an Adjunct to Intensive Behavioral Therapy on Body Weight in Adults With Overweight or Obesity.” JAMA. March 2021. https://jamanetwork.com/journals/jama/fullarticle/2777886

   
   

3. Jastreboff AM, et al. “Tirzepatide Once Weekly for the Treatment of Obesity.” New England Journal of Medicine. 2022. https://www.nejm.org/doi/full/10.1056/NEJMoa2206038

   
   

4. Neeland I, et al. “Changes in lean body mass with glucagon-like peptide-1-based therapies and mitigation strategies.” Diabetes, Obesity and Metabolism, a journal of pharmacology and therapeutics. June 2024 https://pubmed.ncbi.nlm.nih.gov/38937282/

   
   

5. WebMD. “Loose Skin After Weight Loss.” https://www.webmd.com/obesity/loose-skin-after-weight-loss

*The medication names referenced in this article are registered trademarks of their respective owners and are used for informational and educational purposes only. B-Sculpt Medispa is not affiliated with, endorsed by, or sponsored by the manufacturers of these medications.