Skip to content Medically reviewed by Dr. Lauren Weber, MSCP, ABOM
Weight loss medications like semaglutide and tirzepatide have changed how many people manage obesity and metabolic health. They help suppress appetite, regulate blood sugar, and promote impressive fat reduction. Yet for many patients, there’s a growing question about what happens beneath the surface of that transformation, specifically, whether they’re also losing muscle in the process.
At Deeply Vital Medical, where longevity and recovery are part of every patient’s wellness plan, this conversation matters. It’s not just about reaching a lower number on the scale; it’s about maintaining metabolic health and cellular vitality while doing it. That’s where new supportive therapies, including Red Light Therapy, may make a difference.
GLP-1 RA (glucagon-like peptide-1 receptor agonists), such as semaglutide (Wegovy, Ozempic), and dual incretin agents, such as tirzepatide (Mounjaro, Zepbound), help reduce body weight primarily through appetite suppression and delayed gastric emptying. Clinical trials have consistently shown their effectiveness for fat loss. However, several studies also observed that part of the weight lost comes from lean tissue.
In the STEP-1 trial published in the New England Journal of Medicine, researchers led by Wilding et al. found that participants taking semaglutide lost an average of 15% of their body weight. A sub-analysis revealed that while most of this loss was fat mass, about 9–10% was lean mass. Similarly, the SURMOUNT-1 DXA substudy, conducted by Look et al. and published in Diabetes, Obesity and Metabolism, found that approximately 25% of the total weight loss with tirzepatide was from lean tissue.
This doesn’t necessarily mean that GLP-1 medications are harmful to muscle. Fat loss still dominates the composition change, but muscle preservation becomes an important focus, especially for patients aiming for long-term metabolic stability and healthy aging.
Muscle tissue isn’t just about strength or appearance. It plays a key role in regulating blood sugar, hormone balance, and energy production, and is a critical factor in preserving long-term bone health..
When we lose lean mass, we impact our core metabolism:
Losing too much lean mass during weight loss can slow metabolism, reduce functional strength, and make it easier to regain fat later.
That’s why at Deeply Vital Medical, patients using GLP-1 therapy are guided to protect their muscle mass through strategies that include:
These steps help ensure that weight loss remains not only successful but also sustainable. Yet for those experiencing fatigue, slower recovery, or visible changes in muscle tone, adding supportive modalities like Red Light Therapy may help optimize results. Most of the time, you won’t know where your weight loss is coming from. To differentiate mass and track progress: Our Styku 3d Body Composition Scanner accurately distinguishes between fat mass and lean body mass (muscle, bone, water). This is vital because an ordinary scale cannot tell if you’ve lost 5 pounds of fat or 5 pounds of water/muscle.
Red Light Therapy, also known as photobiomodulation, uses low-wavelength Red or Near-Infrared Light to stimulate cellular function. It primarily works at the mitochondrial level, the energy center of most cells, helping improve how efficiently the body converts nutrients into usable energy (ATP).
For patients on GLP-1 medications, this cellular boost can have several potential benefits:
A study by researchers at the University of São Paulo stated that Red Light Therapy improved muscle performance and reduced fatigue markers among physically active individuals. While this research wasn’t explicitly conducted on GLP-1 users, it supports the growing understanding that photobiomodulation helps preserve muscle function under metabolic stress.
As GLP-1 medications lower appetite and promote fat loss, energy intake and nutrient absorption can also decline. Some patients report fatigue or muscle weakness, especially when calorie intake is low or when exercise routines become inconsistent.
By supporting mitochondrial efficiency, Red Light Therapy may act as a bridge, helping the body adapt more smoothly to the calorie deficit created by GLP-1 medications. It doesn’t replace exercise or healthy nutrition, but may make them more effective by improving how cells recover and generate energy.
At Deeply Vital Medical, this approach fits into a broader philosophy: optimizing metabolism at every level, not just through medication but through cellular and structural health. Patients often find that combining Red Light Therapy with their GLP-1 program makes workouts more productive, improves sleep quality, and makes recovery more comfortable.
It’s important to note that while Red Light Therapy has a strong foundation in sports recovery and mitochondrial health, research directly focused on GLP-1-related muscle preservation is still emerging. Current findings suggest it’s a supportive modality, not a substitute for strength training or protein nutrition.
What makes it appealing is its fit within a comprehensive care model. Unlike supplements or medications, photobiomodulation works by encouraging the body’s natural repair and energy systems. For people using GLP-1 medications, this could help counteract fatigue or sluggish recovery that can occur with rapid weight loss.
The goal of medical weight management isn’t only to lose weight but to preserve vitality and structural health. Losing muscle and bone mass can make weight loss less stable and harder to maintain energy levels. Supporting cellular health through Red Light Therapy may help patients recover faster, exercise more consistently, and feel stronger as their bodies change.
As studies continue to explore how photobiomodulation interacts with metabolic treatments, early findings point to a shared pathway, the mitochondria, as a critical target. When your cells function better, every part of your wellness program becomes more effective.
If you’re currently using GLP-1 medications or planning to start, it’s worth asking how you can protect your muscle and bone health during treatment. At Deeply Vital Medical, a Health and Wellness Consultation with Dr. Lauren Weber can help design a comprehensive approach that combines medical expertise, nutrition guidance, and advanced therapies, such as Red Light Treatment, to keep your results strong and sustainable.
Schedule a Consultation with Dr. Weber! Learn how to balance your body composition while optimizing energy, recovery, structural health, and long-term wellness.
