Anbereen Hasan grew up swimming and dabbled in Pilates as an adult, but she wanted to start her weight loss journey after gaining weight in her early 50s. (“It happened to every woman in my family as they got older,” she says.) So, she discussed the option of going on Mounjaro, a GLP-1 receptor agonist, with her doctor in November of 2022.
Her doctor was on board, so long as Hasan also agreed to start resistance training—something she had only done briefly in the 90s with five-pound weights—in order to preserve her muscle mass. “My doctor was pretty clear that I would have to do weight training,” says Hasan.
The 55-year-old found Tina Tang, CPT, a certified personal trainer, strength coach, and founder of Iron Strong Fitness, in April of 2023, via Instagram. “I did a ton of research before I settled on [working with] Tina as a personal trainer,” Hasan says. She liked that Tang was following and referencing Hasan’s endocrinologist in her social media posts. “We did a phone consultation and clicked right away.”
Hasan’s decision to invest in her muscle maintenance made total sense: While muscle loss is an issue for women to consider when losing weight by any means, the impact appears to be more drastic when a weight loss drug is involved, according to a 2024 article in The Lancet Diabetes & Endocrinology. Specifically, studies suggest that muscle loss with GLP-1s can range from 25 to 39 percent of the total weight loss while muscle loss via caloric restriction (with less total weight loss) ranges from 10 to 30 percent.
Because strength training is one of the best ways to preserve and prevent muscle loss, it tracks that a slew of workout and wellness companies (including Equinox and the workout streaming platform Obé) are launching exercise programs specifically marketed toward people on these medications. What’s more, the American Council on Exercise (ACE) just launched a new course around supporting clients who are using anti-obesity medication for trainers and health coaches.
Perhaps in testament to her work with Tang—which involved kettlebells and barbells—Hasan’s initial muscle loss was minimal. Ultimately, she was able to gain muscle and lose fat at the same time—which she also attributes to switching from a high dose (15 milligrams) to a maintenance dose (7 milligrams) of the medication in addition to the lifestyle changes she made. (Hasan was able to keep tabs on her body composition changes with regular InBody scans each time she visited her prescribing doctor, as well as DEXA scans.)
Hasan emphasizes that going from maintenance to actual muscle gaining mode took time—and that it was all about patience and consistency. Today, she lifts weights five times a week (since she’s retired, “I have the time!” she says) and she can see and feel her muscle and strength gains.
Hasan is proof that you’re not destined to lose all your muscle and strength if you decide to go on a weight loss medication. You just have to be smart about your nutrition and training. We spoke with obesity medicine doctors, nutritionists, and trainers for all the intel and tips for maintaining—even gaining!—muscle while on a GLP-1.
Why GLP-1s Make Muscle Maintenance And Gain Tougher
In short, this is thanks to the fact that these drugs are very effective, according to the author of the Lancet article, Carla Prado, PhD, RD, Canada Research Chair in Integrative Nutrition, Body Composition, and Energy Metabolism at the University of Alberta. “[GLP-1s] lead to substantial weight loss which in turn leads to substantial losses of muscle mass,” which can be detrimental, says Prado.
Indeed, the sheer amount of weight loss is one factor that determines how much muscle loss you’re likely to experience on a GLP-1, agrees Ian J. Neeland, MD, director of cardiovascular prevention and co-director of the Center for Integrated and Novel Approaches in Vascular-Metabolic Disease for University Hospitals Harrington Heart & Vascular Institute, who has also authored studies on the subject. “People who lose more weight will be at risk for losing more muscle—it goes in a linear fashion,” Dr. Neeland explains. “Although data is sparse, since people lose so much more weight with GLP-1 medications compared with diet and exercise alone, the amount of muscle loss is more for [those on these] medications.”
Meet the experts: Carla Prado, PhD, RD, is the Canada Research Chair in Integrative Nutrition, Body Composition, and Energy Metabolism at the University of Alberta. Ian J. Neeland, MD, is the director of cardiovascular prevention and co-director of the Center for Integrated and Novel Approaches in Vascular-Metabolic Disease for University Hospitals Harrington Heart & Vascular Institute. Dina Peralta-Reich, MD, is an obesity medicine specialist and founder of New York Weight Wellness Medicine. Tina Tang, CPT, is a certified personal trainer, strength coach, and founder of Iron Strong Fitness.
Other factors that play a role in muscle loss (or maintenance) while on weight loss meds include whether you have certain health conditions (like heart disease and diabetes) as well as the type of medication you take. Some clinical trials show that, while tirzepatide (the active ingredient in Mounjaro and Zepbound) leads to larger weight loss, tirzepatide users also seem to experience less muscle loss compared to those on semaglutide (the active ingredient in Ozempic), Dr. Neeland says. More research is needed to figure out exactly why that is, though. Older and more sedentary people also may be more at risk for higher lean body mass loss, he adds.
Lifestyle factors within your control also play a massive role. For anyone who goes on a weight loss medication, “if they stay active, they exercise, they maintain good nutrition, that all can go a long way to preventing muscle loss and preserving muscle mass with weight loss,” Dr. Neeland says.
Why Preserving Your Gains Is So Critical
Setting aside the fact that building any degree of muscle is typically hard-earned, and therefore, hard to part with, “skeletal muscle is an important organ for overall health, going far beyond its role in physical movement and strength,” says Prado. It’s a “metabolic powerhouse,” she says, since muscle helps regulate blood sugar levels by taking up glucose, which is essential for preventing conditions like insulin resistance and diabetes.
“Substantial losses of muscle can also weaken our immune system, making individuals more prone to infections and reducing their ability to recover from illnesses and injuries,” she says. “Skeletal muscle acts as a storage of amino acids that our bodies rely on during times of stress, injury, and infection.” Muscle loss also often comes along with bone loss, which is particularly worrisome for women in menopause: “We want to maximize muscle to prevent osteoporosis and other complications of aging,” says Dina Peralta-Reich, MD, an obesity medicine specialist and founder of New York Weight Wellness Medicine.
What’s more, if you choose to eventually reduce your medication dose or go off entirely, having more muscle mass helps you maintain your weight loss. (More muscle mass means more calories burned at rest.)
How To Preserve—Even Gain—Muscle Mass On A Weight Loss Drug
“When weight loss drugs are used correctly with the right monitoring and nutritional guidance, you can achieve minimal muscle loss,” says Dr. Peralta-Reich, who adds that the majority of her patients are able to maintain good muscle mass. She attributes this in part to conservative dosing, but also to other factors, which we’ll delve into below.
In terms of whether it’s possible to put on a decent amount of muscle while on GLP-1s, Dr. Neeland says, “no one has the answer to that. I don’t think they have bodybuilders on GLP just yet.” However, general weight loss studies have shown that you can indeed gain muscle when losing weight, says Prado. Dr. Peralta-Reich says the determining factor is whether you’re in the weight loss or maintenance phase: Many women on these drugs will start with a weight loss phase—during which the goal is to decrease fat mass and maintain muscle, per Dr. Peralta-Reich—then shift to a maintenance phase. “During weight maintenance, the goal is to increase muscle mass,” says Dr. Peralta-Reich. So, not only is it possible, it’s encouraged.
Dr. Neeland points out that the path to success in maintaining or gaining muscle while on a GLP-1 is going to look different for everyone. But there are a few universal truths:
Lift weights two to three times a week.
Combining resistance exercise with a calorie deficit helps preserve muscle mass and improves muscle strength during weight loss, according to a 2017 review in Advances in Nutrition.
For general health, Dr. Neeland typically suggests people dedicate one-third of their exercise time to resistance training and two-thirds to aerobic exercise. For those actively losing weight on GLP-1s, he recommends they do half resistance training and half aerobic exercise (which might look like two to three days of each, depending on your current ability level).
For those on GLP-1s who are new to strength training, like Hasan was, the focus should be on learning the basics and building a foundation, Tang says. In general, she says to do two to three full-body workouts a week and to use heavy weights for fewer reps.
Adjust your lifts based on effort, or RPE.
Now, those who have been lifting for a while might actually notice they can’t progressively overload, or even go as heavy or do as much as they could before starting a weight loss medication. “Don’t be married to specific numbers in the gym—the priority [at this time] is weight loss and muscle preservation,” says Tang.
She suggests using rate of perceived exertion (RPE) as your metric while your weight changes. “Following a pounds-specific progressive lifting program wouldn’t be as ideal since one’s weight and body composition is shifting, thus taking away that constant consistent variable by which to compare progress with,” says Tang. As an example: After losing significant weight, back squatting 150 pounds might feel like too much—and trying to do it anyway because it used to feel easy could set you up for injury. For RPE while lifting, Tang suggests going for an eight out of 10 for most lifts.
Once your goal weight is reached, you can go back to aiming for a specific goal, like trying to increase your one rep max for major lifts like squats and deadlifts. Tang says to start by testing your five-rep max for each lift to get a sense of your new current numbers, and build up from there.
Add HIIT training to help stimulate human growth hormone (HGH).
For the aerobic activity you do incorporate, make it higher intensity to help trigger HGH, Tang suggests. A very small study of five women showed that a single bout of HIIT can indeed trigger the body’s natural HGH. Why is HGH important, you ask? It helps regulate muscle function and stimulates protein growth in muscles and muscle tissue, according to an older review in the Journal of Molecular Endocrinology.
Less is more when it comes to HIIT, Tang says. That means you can cap workouts at 20 minutes as long as you work hard during work intervals and actually rest during the rest intervals.
Consume 30 percent of your calories from protein.
“Generally, protein supplementation has been shown to preserve muscle [and] increase muscle synthesis,” says Dr. Neeland. (Dr. Neeland has applied for a grant for a randomized trial to actually look specifically at the impact of GLP on muscle and mitigation strategies, like protein supplementation.) “Shifting from the usual diet, which is about 15 percent protein, to about 30 percent protein may have an impact,” he says.
Research backs this up: Young men who consumed more protein while losing weight and on an intense exercise regiment gained about 2.5 pounds of muscle, while the young men who consumed less protein did not add muscle, according to a 2016 study in the American Journal of Clinical Nutrition.
Prado suggests aiming for 20 to 30 grams of protein per meal (to maximize muscle protein synthesis, the metabolic process by which skeletal muscle proteins are formed) and including a variety of protein sources, like lean meats, fish, eggs, dairy, legumes, tofu, and high-quality protein supplements if needed.
Consider certain supplements.
Good nutrition also means getting the essential vitamins and minerals, says Prado. And while there’s no evidence that people on weight loss medications need more of any one nutrient in particular, considering they are potentially at a greater risk of losing muscle, they can take advantage of additional nutrients that can benefit muscle, such as vitamin D, omega-3 fatty acids, and hydroxymethylbutyrate (HMB). “There is no direct research on the use of these nutrients in this specific context, so this is general advice,” she reiterates.
However, studies have looked at how supplementation—including vitamin D, fish-oil derived omega 3s, and HMB—might help preserve or build muscle, in general, according to a 2017 review in Advances in Nutrition. A meta-analysis showed that vitamin D had a small but significant effect on muscle strength, especially in older people who were deficient, but no effect on muscle mass. A separate study showed that fish-oil derived omega-3s may improve muscle mass, strength, and physical function in older adults with stable weight, and HMB improved both muscle mass and strength in healthy young and older adults. (Remember to always talk to your doc before starting a new supplement!)
Make sure you’re eating enough—full stop.
Tang notes that one major nuance for those on weight loss medications is that they may not have much of an appetite—and this can impact performance in the gym. “I’ve heard from other trainers that have clients on GLP-1s that sometimes the client will be really tired because they don’t have the appetite to eat enough, and they’re not eating enough,” she says.
Dr. Neeland says that it’s crucial for people on these medications not to skip meals. “If you don’t have enough fuel in the tank, you won’t be able to exercise or function very well,” he says. “People have to be mindful to continue adequate nutrition, even if they’re [eating] less food,” he says, adding that they should focus on “high-yield” foods that are protein- and nutrient-rich.
If you’re struggling to eat enough to support your training, consider working with a dietitian for personalized support, Prado suggests.
Keep tabs on your body composition.
Dr. Peralta-Reich regularly monitors her patients’ body composition to prevent significant muscle loss. If she notices a patient is losing too much muscle, for example, she can tweak the dose of their medication or advise them to make other lifestyle or nutrition changes.
Hasan’s doctor does a body composition analysis every time she visits, which allows her to keep tabs on both lean and fat mass. A DEXA scan (which measures lean mass, but not specifically muscle, according to Dr. Neeland) or even an MRI can be the most accurate ways to measure this, but you can also try a scale that measures body comp or even use a tape measure.
Talk to your doctor about adjusting your dose.
Maintain open communication with your healthcare provider, as your doctor can help guide you as to whether you’re losing too much muscle and potentially adjust your dose or make other changes.
In the future, there may be other pharmacologic therapies available that people can try in addition to GLP-1s to help prevent muscle loss, Dr. Neeland says. “[Muscle loss] is a side effect that many people don’t anticipate or think about, and for some people it doesn’t become a big deal, but for others it could.”
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