Glucagon-like peptide-1 (GLP-1) meds like Ozempic® and Rybelsus® mimic the body’s natural hormones to reduce appetite and slow down the movement of food from the stomach to the small intestine. Now that these drugs have been on the scene for a few years, we’ve had a chance to witness their impressive results for weight loss. According to a 2021 study published in the New England Journal of Medicine, the average user loses 14.9 percent of their body weight after taking a semaglutide (a type of GLP-1 prescription drug) for 68 weeks. (Interested in exploring whether medical weight loss is right for you? Learn more at Whole Health Rx by The Vitamin Shoppe.)
But with all of the pounds users are collectively shedding, are they also losing some things they want to keep? Recently, some health experts and GLP-1 users have raised the alarm that a notable portion of the weight lost on these meds isn’t fat, but muscle. A few reports have even indicated that these drugs could diminish bone health. Given the important roles that healthy bones and muscles play in long-term wellness, independence, and quality of life, these revelations might leave you wondering if the benefits of a GLP-1 drug outweigh the costs.
Here’s a closer look at what we know about the relations between GLP-1 drugs and muscle and bone health, and what users of these meds can do to promote strong bones and muscle mass maintenance.
- ABOUT OUR EXPERTS: Melissa Mitri, M.S., R.D., is a dietitian specializing in weight loss. Dr. Yash Mehta, D.O., is an interventional spine and sports medicine physician with the Virginia Spine Institute.
Do GLP-1s Cause Muscle and Bone Loss?
When considering the research on GLP-1s, it’s important to keep in mind that these medications are fairly new. Ozempic, the first weight-loss drug of its kind, was only approved by the FDA in 2017. Because of their “young” age, research on them isn’t nearly as well established as on many other, older meds.
Read More: Proof That Building Muscle Is A Must For Long-Term Health
For this reason, it’s not surprising that experts like Melissa Mitri, M.S., R.D., a dietitian specializing in weight loss, say that studies on GLP-1s and muscle health are inconsistent. “In a research review that evaluated over 25 studies, at least half of the studies showed 20 to 50 percent of weight loss achieved on GLP-1s was muscle loss, which is significant,” she points out. However, other studies, such as one from 2023, showed a lower percentage of muscle loss, with zero to 19 percent of total weight loss coming from muscle.
According to Mitri, it’s not just GLP-1s’ recent origins that make research hard to interpret. “There are a lot of factors that may vary the amount of muscle mass lost, such as the type of GLP-1 used, the dose, other medications taken, amount of exercise, medical status, and more.” As such, there doesn’t seem to be a “typical” amount of muscle mass lost on these medications.
The same appears to be true for bone loss. “The jury is still out about the potential link between GLP-1 medications and increased fracture risk,” says interventional spine and sports medicine physician Dr. Yash Mehta, D.O., of the Virginia Spine Institute. “Some studies have shown that GLP-1 medications decrease bone health, while others have shown the opposite to be true, with increases in bone health.” Two different studies from 2021, for example, indicated that GLP-1s could cause either bone loss or bone growth under different circumstances and in different parts of the body. Future research may shed more light on exactly how much bone (if any) most people can expect to lose while on one of these medications.
Why GLP-1s Might Make You Lose Muscle and Bone
Though science is clearly still sussing out just how much GLP-1 meds impact muscle and bone health, we do have some clues as to why these medications could have downstream effects on these parts of your body.
On the muscle mass front: “Based on the research to date, GLP-1s do not seem to directly cause muscle loss,” says Mitri. “Instead, the muscle loss is a side effect of total weight loss.” It’s not just Ozempic-assisted pound-shedding that could do this. Any rapid weight loss can decrease lean muscle mass for a simple reason: When calories are scarce, your body taps into its reserves of fat and muscle to meet energy needs.
Read More: How to Fill Nutritional Gaps If You’re Taking a GLP-1 Weight Loss Drug
As for bone loss, the possible underlying mechanism is less clear. “Some literature hypothesizes the risk to be inherent to an underlying diabetic condition, and not an additional risk with taking the medications,” says Mehta. (Many GLP-1 drugs are intended for managing diabetes, not just weight loss.) “Other studies have shown that, in adults with increased fracture risks, the GLP-1 medications can further the underlying risk.” Even if GLP-1s don’t directly act upon bones, though, Mehta says that rapid weight loss alone can lessen bone density.
How to Know If You’re Losing Muscle or Bone Strength
In some cases, you might be able to tell you’re losing muscle on a GLP-1 just by looking in the mirror or assessing how your clothes fit. But there are other ways to keep tabs on muscle and bone health. Weight checks and DEXA scans (which measure the thickness and strength of bones) can both help monitor bone and muscle health, according to Mehta. If you’re concerned about declining muscle or bone strength, ask your doctor about using these methods.
On the muscle front, you can also use your own weightlifting performance as a yardstick of muscle loss, Mehta suggests. Any notable declines in strength suggest your muscle mass has taken a downturn. If you already test your maximum lifting capacity, keep on keeping on. Otherwise, consider checking in with a certified personal trainer or physical therapist. They can help you measure and track your lifting ability.
How to Support Muscle and Bone Health on a GLP-1 Drug
If you’re on a GLP-1 for weight loss, you probably want to hang onto muscle and bone as you say goodbye to fat. To do so, start with a good strength-training routine. (The going recommendation is at least two days of full-body strengthening exercises per week.) Hitting the weights at the gym is a great idea, but you can also incorporate strength training into your daily activities, suggests Mehta. Go ahead, crank out a few curls with the milk jug before putting it away, or drop into a few squats before grabbing something out of that low cabinet. These activities support muscle mass maintenance and even growth, helping you get ahead of muscle losses before they occur. Resistance training is also recommended for supporting bone density, so it’s a win-win.
Of course, food choices are also important for keeping muscles and bones in good shape. According to Mitri, a muscle- and bone-protecting diet is all about protein. “There is no exact amount of protein required for everyone on GLP-1 medications. Overall, it can range from 1.2 to two grams per kilogram of body weight (or more) to preserve muscle mass and support a healthy metabolism, which can help reduce weight regain over time.” For someone who weighs 200 pounds, that’s between 109 and 181 grams of protein per day. Lean protein sources to focus on include fish, chicken, turkey, eggs, dairy foods, tofu, beans, lentils, nuts, and seeds.
Drugs like Ozempic and Wegovy are notorious for diminishing your appetite, so if you feel you’re not able to get enough protein in via your meals, consider adding a protein powder to your routine. “I love the Orgain brand plant-based protein powder because it tastes great, provides 21 grams of quality plant protein per serving, and contains no artificial sweeteners,” Mitri says. You might also try eating smaller, more frequent meals high in protein throughout the day—and focusing on consuming higher-protein foods first before turning to others.
Aside from protein, the nutrients calcium and vitamin D are also essential for long-term bone health. Calcium is the major building block of bone—and since the body can’t produce calcium from scratch, we have to get it from food. According to the NIH, all adults ages 19 to 50 need about 1,000 milligrams of calcium per day. Milk, dark leafy greens, and beans all provide some of the mineral—but you might consider supplementing if you don’t meet that daily mark. Vitamin D, meanwhile, is a must-have for absorbing and using the calcium you consume. Adults should get about 600 IU (15 micrograms) of vitamin D per day. You’ll find some in fatty fish and egg yolks, but many Americans are deficient. A vitamin D supplement can help fill the gaps and ensure you’re meeting your needs and getting your bones the calcium they need.
The Bottom Line
Though it’s not yet totally clear exactly how GLP-1 drugs impact muscle and bone (and your personal experience could differ from someone else’s), it’s smart to take steps to protect these aspects of health while on these drugs. By bumping up your strength training and focusing on the right foods, you’ll increase the chances of hanging onto muscle and bone as the pounds drop off.