GLP-1 Medications and Muscle Loss: Causes & How to Prevent It

GLP-1 medications like Ozempic have been life-changing — and even life-saving — for many people. They support weight loss, improve metabolic health, help manage conditions such as type 2 diabetes, and can improve quality of life.

As with any significant weight loss, though, there’s another piece I think deserves attention: some of the weight you lose can come from muscle, not just body fat.

Fortunately, how much muscle you maintain isn’t entirely out of your hands. Taking a thoughtful approach to weight loss can help you hold on to more muscle along the way.

What Muscle Loss on a GLP-1 Actually Looks Like

Yes, some muscle loss can happen while taking a GLP-1 medication. But there’s nuance we shouldn’t overlook.

When you lose a significant amount of weight, you typically lose both fat and lean mass. Some GLP-1 studies estimate that roughly 25-40% of weight lost may be lean mass — but lean mass isn’t synonymous with just muscle.

Lean mass includes muscle, but it also includes water, organs, connective tissue, and other tissues. So if someone loses 40 pounds and 10 pounds are measured as lean mass, that doesn’t mean they lost 10 pounds of muscle.

This also isn’t unique to GLP-1 medications. Some loss of lean tissue commonly occurs with significant or rapid weight loss, regardless of how that weight is lost. Current research suggests that the changes seen with GLP-1s are largely proportional to the amount of weight lost.

Still, preserving muscle matters for strength, physical function, and healthy aging. Eating enough protein and resistance training are two of the most important ways to help protect it while you lose weight.

Dr. Devon Allen, Top Nutrition Coaching's medical contributor, points to two drivers behind muscle loss on these medications, and why it should be tracked from the beginning of treatment:

"Muscle loss on GLP-1 is a big concern and can result in weakness, decreased endurance, and increased fatigue. Muscle loss can result from too rapid weight loss and from decreased protein intake. Both can result in the body breaking down its own muscle to use for glucose for nutrition and brain health. If the body is getting inadequate nutrition, it will use muscle to replace it. This needs to be monitored from the start by the prescriber and the dietitian."

Why Muscle Matters for Your Health

Muscle does a lot more than make you feel and look stronger. These 2021 and 2025 reviews delve into such mechanisms, but here’s the simple yet still compelling version: Muscle helps you move, plays a major role in blood sugar control, and supports how much you can physically do on your own as you get older.

It also uses energy around the clock. Muscle burns calories even at rest, so losing muscle can contribute to a decrease in how many calories your body uses each day. The effect isn’t huge — keeping muscle isn’t a way to dramatically speed up your metabolism — but preserving it can help limit some of the drop in energy expenditure that occurs during weight loss.

Muscle also helps control blood sugar (glucose) levels. After you eat carbohydrates, skeletal muscle takes up glucose from your bloodstream and either uses it for energy or stores it as glycogen for later. Regularly using your muscles through exercise can also improve insulin sensitivity, helping your body move glucose out of the bloodstream more effectively.

Then there’s what your muscles allow you to do. Getting out of a chair, carrying groceries, climbing stairs, and catching yourself when you lose your balance all require muscle and strength. Preserving both becomes increasingly important with age, as muscle mass and strength naturally decline.

Losing muscle during weight loss can have consequences later, too. If you regain some of the weight but don’t regain the muscle you lost along with it, your body composition may be different than it was before. Over repeated cycles of weight loss and regain, that can result in proportionally more body fat and less lean mass.

The goal during weight loss isn’t simply to make the number on the scale smaller. Ideally, you want as much of that loss as possible to come from body fat while keeping the muscle that supports your metabolism, blood sugar control, strength, and ability to stay active.

Who’s Most at Risk for Muscle Loss?

Anyone can lose muscle, particularly when losing weight. But some people are more susceptible because of age, activity level, hormonal changes, nutrition, or certain health conditions.

A few groups should pay closer attention:

• Older adults: You naturally lose muscle mass and strength as you age. The body also becomes somewhat less responsive to protein, so maintaining muscle can take more effort than it did earlier in life.
• People who aren’t very active: Muscle needs regular use. Without resistance exercise — or during long stretches of very little movement — the body has less reason to maintain it. This is also why muscle can decline quickly during bed rest, hospitalization, or recovery from an injury.
• People during and after menopause: Hormonal changes during this stage of life can contribute to declines in muscle mass and strength. Losing weight at the same time can make preserving muscle more difficult, particularly with a large calorie deficit.
• People with certain chronic illnesses: Some illnesses — like chronic obstructive pulmonary disease, cancer, chronic kidney disease, and inflammatory conditions — are linked to a higher risk of muscle loss. Illness can affect appetite and activity while also changing how the body builds and breaks down muscle.
• People who aren’t eating enough: Consistently eating too few calories or too little protein can make it harder to maintain muscle. During weight loss, both can happen unintentionally as portions get smaller.

You may come across the term sarcopenia, especially when reading about muscle and aging. It describes a progressive decline in muscle strength and mass. Strength and physical function are part of the picture, too, so it isn’t simply a term for having less muscle as you get older.

Dr. Allen recommends addressing muscle preservation before it becomes a problem: "A risk of unwanted muscle loss inherently exists in older adults and in postmenopausal women, and that risk will be compounded in patients taking GLP-1s. Therefore, it is extremely important to address this from the start in these patients. Increasing weight-bearing activity and appropriate nutritional counseling with the dietitian is of the utmost importance."

None of these risk factors guarantees you’ll lose a significant amount of muscle. However, they do make adequate protein and resistance training especially worth paying attention to.

How to Protect Your Muscle While Taking GLP-1s

Losing some lean mass during weight loss isn’t unusual, whether you’re taking a GLP-1 medication or losing weight without one. The concern with GLP-1s is that appetite can drop enough that you’re eating substantially less — including less protein — at the same time you’re losing weight quickly.

The Massachusetts General Hospital cites two main levers to protect muscle while taking GLP-1s: 1) getting enough protein and 2) using your muscles against resistance.

Getting Enough Protein Every Day

Protein provides the amino acids your body uses to maintain and repair muscle. During weight loss, getting enough helps reduce how much lean mass you lose.

For adults taking a GLP-1, a commonly recommended range is 1.2 to 1.6 grams of protein per kilogram of body weight (g/kg) per day, although individual needs vary.

To estimate that in grams:

Your weight in pounds ÷ 2.2 × 1.2-1.6

For someone who weighs 180 pounds, or about 82 kilograms, that’s roughly 98 to 131 grams of protein per day.

The calculation may be the easy part. Eating that much can be harder when a GLP-1 has significantly reduced your appetite.

Rather than trying to catch up with a large serving at dinner, include some protein each time you eat. When possible, prioritize high-quality protein sources that provide all nine essential amino acids your body can't make on its own. Eggs, Greek yogurt, cottage cheese, chicken, fish, lean meat, and dairy or soy foods are good examples.

Plant proteins count, too. Tofu, tempeh, beans, lentils, nuts, seeds, and whole grains can all contribute to your daily protein intake. Eating a variety of protein-rich foods throughout the day helps provide the amino acids your body needs.

If a full meal is unappealing, a smaller serving of Greek yogurt or cottage cheese may be easier to manage. Protein powder can help here, too. A shake or scoop mixed into oatmeal, yogurt, or a smoothie can provide another 20 to 25 grams without requiring a large meal.

Adding Strength Training to Your Routine

Protein provides the building blocks your body needs to maintain muscle. Resistance training gives your muscles a reason to hold on to that tissue during weight loss.

If you’re new to strength training, you don’t need to jump into long workouts or a complicated program. Start with two short sessions per week and a handful of basic exercises. Chair squats, wall or countertop push-ups, resistance-band rows, and step-ups are all approachable options.

Focus on getting comfortable with the movements at first. Once an exercise starts to feel easier, make it a little more challenging by adding a few repetitions, using more resistance, adding another set, or trying a harder variation. This gradual increase in difficulty — also known as progressive overload — is what helps you continue building strength.

Eventually, work toward at least two full-body strength sessions each week that cover the major muscle groups. The sessions don’t have to be long, but they should feel challenging enough that your muscles have to work.

If you’ve never strength-trained before, you might consider meeting with an exercise professional, like a certified personal trainer. They can help you learn proper technique and ensure you’re progressing in a well-structured workout plan. Even a few sessions can make it easier to continue confidently on your own.

Supplements That May Help

Supplements come after protein and resistance training, not in place of them, and it's always best to talk to your prescriber before starting any supplements. Of the options marketed for muscle, creatine has considerably more research behind it than most.

Creatine for Muscle Support

Creatine is a compound your body naturally makes and stores primarily in muscle. It helps supply energy during short, demanding efforts such as lifting weights.

Taking creatine alongside resistance training can improve strength and support gains or maintenance of lean mass. Creatine monohydrate is the form with the most research behind it, and a typical daily dose is 3 to 5 grams.

A loading phase isn’t required. Taking it consistently is more important than taking it at a particular time of day, too.

Creatine can cause a small increase in body weight when you first start taking it because it draws more water into muscle. That’s water, not body fat.

Other Helpful Supplements

Other supplements, including HMB, fiber, and probiotics, may also be useful depending on your needs.

HMB (short for beta-hydroxy beta-methylbutyrate) is a substance your body naturally produces when it breaks down leucine, an amino acid found in protein. Some research suggests HMB supplements may help preserve muscle, particularly in older adults or during periods of reduced calorie intake, although the evidence isn’t as established as it is for creatine.

A 2025 review suggests that fiber and probiotic supplements may be helpful while taking GLP-1s. Fiber may help with constipation and stool consistency, while probiotics may support regular bowel movements and a healthy gut microbiome.

Dr. Allen takes a conservative position on supplements generally, including those marketed for muscle preservation. "Caution needs to be maintained when considering dietary supplements that are not monitored by the FDA or overseen by a dietitian in collaboration with the prescriber," Dr. Allen says. "I do not recommend that any patient start any such supplements without consultation first."

Things to Avoid When Maintaining Muscle Mass

If you’re getting enough protein and strength training regularly, you’re already covering two of the biggest pieces of muscle preservation. Eating enough overall and staying active throughout the week help support those efforts, too.

Habits That Accelerate Muscle Loss

Cutting calories too aggressively can mean losing more than body fat. Larger calorie deficits increase the risk of losing lean mass, too. A quickly dropping scale can feel like progress, but the goal isn’t simply to lose as much weight as possible — it’s to preserve as much muscle as you can while losing fat.

Moving less can happen without you realizing it, especially if eating less leaves you with less energy. You may still get your workout in but spend more of the rest of the day sitting. Regular movement gives your muscles more opportunities to work throughout the day, while extended periods of inactivity can contribute to losses in muscle and strength.

Adding more exercise while continuing to eat less isn’t necessarily better. Resistance training gives your muscles a reason to stick around, but your body still needs enough protein, energy, and recovery to respond to that training. If your energy is consistently low or your workouts and everyday activities are becoming harder, simply adding more exercise may not be the answer.

Common Diet Mistakes

Letting protein fall by the wayside as your portions get smaller is an easy one, particularly when you aren’t very hungry. If your usual eggs and toast turn into a piece of toast, for example, you haven’t just made breakfast smaller — you’ve removed most of its protein.

Leaving most of your protein for the end of the day can also make your target much harder to reach. Skipping a meal isn’t inherently a problem, but fewer meals mean fewer opportunities for protein. If you skip breakfast and eat a light lunch, you may arrive at dinner with most of your daily protein still ahead of you — and a reduced appetite can make that difficult to fit into one sitting.

Getting too little nutrition from the food you are eating matters when your overall intake is lower. You don’t need every meal to be nutritionally perfect, but regularly including foods that provide protein, fiber, vitamins, and minerals helps you get more nutrition from the amount you can comfortably eat.

The aim isn’t to eat as little as you can tolerate. It’s to create enough of a calorie deficit to lose fat without making it unnecessarily difficult to retain your muscle.

Avoiding Nutrient Deficiencies While on GLP-1s

Eating smaller portions means you’re also taking in smaller amounts of the vitamins and minerals those foods provide. Vitamin D, vitamin B12, iron, calcium, and magnesium are among the nutrients that may fall short while taking a GLP-1 medication.

Low levels can show up in different ways. Fatigue or weakness, muscle cramps, numbness or tingling, and hair loss are all worth mentioning to your prescriber. Ongoing nausea or vomiting also deserves attention, since it can make it especially difficult to eat enough and increase the risk of nutrient deficiencies.

Rather than guessing based on symptoms, talk with your prescriber about whether bloodwork makes sense for you. A registered dietitian can also look at what you’re eating and identify nutrients that may be falling short before automatically adding individual supplements.

If you’re regularly unable to eat a varied diet, a daily multivitamin may help cover some gaps. Individual supplements, such as iron or vitamin D, are better based on your needs rather than taken automatically.

Nutrition needs can look quite different from one person to the next on a GLP-1. How much you’re able to eat, the foods you tolerate, other medications you take, and any deficiencies you had before starting treatment all affect what you may need.

How Working With a Registered Dietitian Helps

Eating on a GLP-1 can change from week to week. Your appetite may drop after a dose increase, foods you normally rely on may stop sounding good, or nausea and early fullness may make your usual meals difficult to finish. A registered dietitian can help you adjust without losing sight of what you're actually getting from your diet.

A dietitian can look at the bigger picture — how much you’re eating, where your protein is coming from, which foods you’re tolerating, and whether weight is coming off at a pace that supports your health and muscle. As your appetite and intake change, they can adjust your nutrition so you're not simply eating less, but still getting enough of what you need.

This kind of support doesn’t have to wait until you’re struggling. Regular check-ins give you a chance to adjust your nutrition as your medication, appetite, weight, and tolerance change.

Top Nutrition Coaching connects you with registered dietitians who can provide one-on-one nutrition support while you’re taking a GLP-1 medication. Many insurance plans include nutrition counseling benefits, which may reduce or eliminate the cost of appointments depending on your coverage. You can also check if your insurance covers a dietitian before your first appointment.

Considering a GLP-1? Here's How Top Nutrition Coaching Can Help

If you're exploring GLP-1 medications for weight loss or blood sugar management, medicine is only half the answer. Top Nutrition Coaching can match you with a licensed prescriber to see if a GLP-1 prescription online is right for you, then pair you with a registered dietitian to support you through the process — helping manage side effects, protect muscle mass, and build habits that make your results last. Many insurance plans cover dietitian sessions, and some plans cover them at no additional cost, though coverage varies by plan and isn't guaranteed. A prescription requires a medical consultation and isn't guaranteed either. Take our quick quiz to see what your insurance covers and get matched with support.

What to Expect Long-Term

GLP-1 medications can help with weight loss, blood sugar control, and other measures of metabolic health over the long term. With continued treatment, weight loss typically slows and eventually levels off. That plateau doesn’t mean the medication has stopped working. Maintaining the weight you’ve lost is part of what the medication is helping you do.

If you stop taking a GLP-1 medication, appetite can increase again, and regaining some weight is common. In a follow-up of the STEP 1 trial, participants who stopped semaglutide regained about two-thirds of the weight they had lost over the following year. This supports the use of GLP-1 medications as long-term treatments for chronic weight management rather than short-term weight-loss tools.

What you eat and how you move still matter during treatment and if you eventually stop. Getting enough protein and resistance training can help preserve muscle, while regular meals, a varied diet, and regular physical activity can help you meet your nutritional needs and maintain improvements in your health.

The scale isn’t the only way to measure how well treatment is working. Changes in strength, blood sugar, blood pressure, and how easily you can do everyday activities can all tell you something about your health, even when your weight stays the same.

If you’re considering changing your dose or stopping your medication, talk with your prescriber first. 

Frequently Asked Questions

Do GLP-1s cause muscle loss?

Some muscle loss can occur while losing weight on a GLP-1, just as it can with weight loss in general. However, studies often measure changes in lean mass, which includes muscle as well as water, organs, and other tissues, so a decrease in lean mass doesn't necessarily mean the same amount of muscle was lost. Current research suggests that much of the change may be a normal response to significant weight loss rather than an effect unique to GLP-1 medications.

How much muscle loss is normal on GLP-1 medications?

There isn’t an exact amount of muscle loss that’s considered normal while taking a GLP-1. Studies show that lean mass often decreases as weight comes down, but lean mass includes more than muscle, making it difficult to say exactly how much muscle is lost. The amount can also vary based on age, starting muscle mass, rate of weight loss, protein intake, and physical activity.

How can you prevent muscle loss while taking GLP-1s?

Eating enough protein and resistance training are two of the best ways to help prevent muscle loss while taking a GLP-1. Because these medications can significantly reduce appetite, getting enough protein may take more planning than it did before. Regular strength training gives your body a reason to maintain muscle as you lose weight, while protein provides the building blocks needed to repair and maintain it.

Does semaglutide cause muscle loss?

Some muscle can be lost while taking semaglutide, particularly as you lose weight. However, research has not established that semaglutide directly causes muscle loss beyond what can occur with significant weight loss itself. Most studies measure lean mass, which includes muscle but also water, organs, bone, and other tissues, so a decrease in lean mass doesn’t necessarily mean the same amount of muscle was lost.

What protein intake is recommended to reduce muscle loss on GLP-1s?

Many experts recommend aiming for 1.2 to 1.6 grams of protein per kilogram of body weight daily during weight loss to help preserve muscle, though individual needs vary and your healthcare team may base this on an adjusted or target body weight. Spreading protein throughout the day — such as aiming for around 25 to 30 grams at meals — and pairing adequate protein with resistance training can further support muscle maintenance.

How much of weight loss on GLP-1s comes from muscle versus fat?

Most weight lost on GLP-1 medications comes from fat. Studies generally find that about 60-80% comes from fat mass, while the remainder may come from lean mass. Lean mass includes muscle, but also water, organs, and other tissues, so it isn’t accurate to assume all lean mass lost is muscle.

Can you build muscle while taking GLP-1s?

Yes, you can build muscle while taking a GLP-1, especially when you regularly strength train and get enough protein. Building muscle may be a little more challenging during periods of active weight loss because you’re eating fewer calories overall, but you can still make meaningful improvements in strength, muscle health, and body composition along the way.

Do you need strength training while on GLP-1 weight loss treatment?

Strength training is strongly recommended while taking a GLP-1 because it helps preserve muscle and strength as you lose weight. Protein matters too, but resistance exercise gives your muscles the stimulus to stay strong, making the two most effective when used together.

How do I know if I'm losing muscle or just body fat on GLP-1s?

A regular scale can tell you that your weight is changing, but not what type of tissue you’re losing. Body composition tests such as a DXA scan can estimate changes in fat and lean mass, while changes in strength and physical function can offer additional clues about muscle health. Keep in mind that lean mass includes more than muscle, so a drop in lean mass on a scan doesn’t mean you’ve lost the same amount of muscle.

Is muscle loss from GLP-1s reversible after stopping the medication?

Potentially, but we don’t have enough human research to know how much muscle is naturally regained after stopping a GLP-1. Muscle can generally be rebuilt with adequate nutrition and resistance training, but weight regained after stopping the medication may include more fat than lean tissue. This is another reason why supporting muscle with protein and strength training is important both during and after treatment.