Chances are you’ve heard buzz words like “Ozempic” and “semaglutide” more times than you can count this past year. These wildly popular weight loss drugs have helped people shed a lot of pounds. But not all that weight is fat.

Rapid weight loss, like that experienced when taking Ozempic and other glucagon-like peptide-1 (GLP-1) agonist drugs, causes increased muscle loss alongside fat loss.

Why should I care about muscle loss?

I’m glad you asked! One of the most important factors in healthy aging and longevity is how much muscle you have on your body. Having an appropriate amount of muscle for your overall body weight presents a myriad of benefits, which we regularly talk about at Hyatt Strength + Wellness.

Keeping yourself well-muscled and strong throughout life helps with injury prevention and chronic pain, keeps your metabolism from slowing (which helps with weight management), and protects your bones and joints from age-related osteopenia and sarcopenia.

Muscle is critical to wellness and movement functionality. Regaining lost muscle is increasingly difficult with age–plus it takes a lot of work and patience–making it far superior to hold onto the muscle you already have.

Back to the weight loss drugs–how do they work?

GLP-1 agonists are a relatively new class of medications developed to treat type 2 diabetes. They help manage blood sugar levels by encouraging the release of more insulin from the pancreas. Additionally, they cause reduced appetite and delayed glucose absorption due to slower gastric emptying.

Essentially, people taking a GLP-1 agonist don’t get as hungry and feel fuller longer, leading to a sometimes drastic reduction in energy consumption. In other words, they end up eating a lot less calories, leading to weight loss.

GLP-1 agonists have only recently been approved for weight loss by the FDA, putting the drugs in sudden high demand, leading to widespread shortages. Versions of these drugs are also available at compounding pharmacies. However, it’s important to note that compounded GLP-1 agonists may not be the same formulas as the brand name drugs, and sometimes have different effects on the body due to their varying chemistry. Compounded drugs are also not FDA approved, so it’s best to do your research, and talk to a trusted doc, before taking them.

Where does muscle loss come in?

While taking GLP-1 agonists, many people report a lack of desire to eat and a significant disinterest in food. This can lead people to eat very few calories, leaving their bodies nutrient and energy deficient. Twenty-five percent of weight that’s lost is muscle and bone. For those who chronically under-consume food (eating less than 1200-1500 calories per day), that percentage goes up, even as high as 50%. That means it’s possible to lose weight and end up with the same (or worse!) body fat percentage than when you started. Weight loss without an improvement in overall body fat percentage, likely won’t lead to markedly improved health.

Hold on to that muscle

If you are taking a GLP-1 agonist, or are thinking about it, it’s important to consider how to support the process with well planned, consistent strength training and nutrition. Some things to aim for include:

  • Strength train with relatively heavy loads 2-3 times per week
  • Prioritize compound lifts (think squats, deadlifts, lunges, bench presses, shoulder presses)
  • Implement progressive overload into your weightlifting program to keep you getting stronger and maintaining your lean muscle mass
  • Make sure you’re eating enough protein, fiber, and micronutrients (seek reputable, professional nutrition advice if you’re not sure)
  • Have a solid exit plan when you discontinue use of the drug

That last bullet point is worth restating. Have a solid exit plan, nutritionally, when you’re ready to discontinue use of the drug. When you take in less calories than you did before, for a prolonged period, your body slows its metabolism to avoid starvation. Effectively, the body continually tries to only use the energy you give it, so if you give it less energy by eating less calories, it slows down its metabolic processes to conserve energy.

Additionally, if you have lost weight, the amount of calories needed on a baseline to keep you alive, in a state of complete rest (called Basal Metabolic Rate or BMR), is less than before. This is because smaller bodies, with less overall mass, require less energy.

Your BMR will also decrease the less muscle you have. Muscle is metabolically active and requires a lot of energy to use. The same is not true for fat, so having the most muscle possible helps keep you eating more without gaining body fat.

A sudden shift to eating more calories after discontinuing the use of a GLP-1 agonist will lead to weight gain. Studies have shown that most participants taking a GLP-1 agonist regained two-thirds of their lost weight within one year after ceasing treatment. Healthcare’s answer to this? Keep people on the drug indefinitely…the effects of which are not well understood, to say nothing of the significant expense.

This article is not medical advice and should not be taken as such. Please consult a qualified healthcare provider as necessary. If you are on a GLP-1 agonist, or plan to start one, be sure to let your trainer know so they can provide you with the best possible exercise programing to support the process.

Hyatt Training personal trainer intern Elana WittAuthor Elana Witt is a personal trainer and nutrition coach at Hyatt Strength + Wellness. She believes all people possess the ability to get stronger and feel better, no matter where they’re starting from. Through learning correct, functional movements, she wants each of her clients to better understand their body and their capabilities while feeling empowered to achieve their goals. Elana is a NASM certified personal trainer and Precision Nutrition level 1 coach. Learn more about Elana, or get in touch with her by emailing us at

Hyatt Strength + Wellness is a collective of certified, enthusiastic and innovative personal trainers in Portland, Oregon. To read more fitness related posts like this one, follow this link.


Cassata, C. (2023, May 2). Ozempic may make your muscles and bones weaker. Healthline.

Graves, G. (n.d.). Weight loss medications risky for older adults?. AARP.

Shaefer, C. F., Jr, Kushner, P., & Aguilar, R. (2015). User’s guide to mechanism of action and clinical use of GLP-1 receptor agonists. Postgraduate medicine, 127(8), 818–826.

Wilding, J. P. H., Batterham, R. L., Davies, M., Van Gaal, L. F., Kandler, K., Konakli, K., Lingvay, I., McGowan, B. M., Oral, T. K., Rosenstock, J., Wadden, T. A., Wharton, S., Yokote, K., Kushner, R. F., & STEP 1 Study Group (2022). Weight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension. Diabetes, obesity & metabolism, 24(8), 1553–1564.