In the battle of the obesity bulge, glucagon-like peptide-1 receptor agonist medications — aka GLP-1s such as Wegovy and Zepbound — have changed the game for some people who’ve struggled to lose weight through diet and exercise alone.
First developed to treat Type 2 diabetes, GLP-1 medications help regulate blood sugar but have the added benefit of suppressing appetite and helping people eat less. As such, they can lead to significant weight loss for many users. These medications, however, can have some side effects, including muscle loss. We’ll dive into why muscle loss happens and how can you limit this problem when taking a GLP-1 medication and protect your strength.
What Are GLP-1 Medications and How Do They Work?
GLP-1 medications work by mimicking a natural hormone in your body galled GLP-1 or glucagon-like peptide-1. This hormone can make powerful adjustments in the body that help you consume fewer calories and trigger weight loss, explains Katelyn Tribble, a registered dietitian and certified specialist in obesity and weight management with the Orlando Health Jewett Orthopedic Institute.
She notes that these medications help with weight loss and managing blood sugar by:
1. Increasing insulin: Helping the body convert sugar into energy and managing blood sugar levels
2. Slowing down digestion: Keeping you feeling fuller for longer
3. Silencing food noise: Reducing cravings in the brain’s reward center
Types of GLP-1 medications
This class of medications, also sometimes referred to as incretin mimetics and GLP-1 analogs, includes the following:
| Common brands | Active ingredient |
| Byetta, Bydureon | Exenatide |
| Trulicity | Dulaglutide |
| Saxenda, Victoza | Liraglutide |
| Adlyxin | Lixisenatide |
| Ozempic, Wegovy, Rybelsus | Semaglutide |
| Mounjaro, Zepbound | Tirzepatide |
The most heralded of the current bunch of GLP-1 medications specifically approved by the Food and Drug Administration for weight loss include:
— Wegovy, a once-weekly semaglutide injection featuring a higher dose of the active ingredient found in the diabetes medication Ozempic
— Zepbound, a once-weekly tirzepatide injection featuring a higher dose of the active ingredient found in the diabetes medication Mounjaro
[READ: Semaglutide vs. Tirzepatide for Weight Loss]
Why GLP-1 Medications Cause Muscle Loss
It’s a biological fact: When you lose weight, you’re losing a combination of fat, water and muscle. However, GLP-1s can accelerate muscle loss.
The medication doesn’t attack muscle directly. Instead, it suppresses appetite so effectively that patients often enter a severe calorie and protein deficit. Muscles are built from protein, so that reduction can lead to loss of muscle mass over time.
“Humans turn food into energy, which creates fuel for our bodies,” Tribble says. But sometimes, “the medication can suppress the appetite so much that the patient isn’t eating enough to meet the energy demands of their body. When this happens, the body must break down muscle to make energy.”
This means that GLP-1 medications don’t cause muscle loss in and of themselves, but rather reduce appetite to the point where patients on these medications don’t eat as much as they need to in order to maintain their body composition. This can lead to muscle wasting as the body breaks down muscle to fuel activity.
What’s more, the older you get, the more muscle mass you lose, even if you’re not on a GLP-1, says Dr. Samuel Golpanian, a double board-certified plastic surgeon in Beverly Hills. “After about age 30, your muscle mass reduces by about 1% per year.”
This normal, age-related muscle loss that we all must deal with is called sarcopenia. So people in their 40s and 50s who are taking weight loss medications “super-charged” this muscle loss because of the drop in protein intake.
[READ: GLP-1 Side Effects: Expert Tips to Manage Nausea, Constipation and Weight Loss Fatigue]
How to Reduce GLP-1-Related Muscle Loss
While some lean mass loss is inevitable, you can mitigate the damage, Golpanian says. Preserving muscle is vital because muscle tissue drives your metabolic rate, the more muscle you lose, the harder it becomes to keep the weight off long term.
Ways to reduce GLP-1-related muscle loss include:
— Prioritizing protein
— Eating enough calories
— Incorporating resistance training
— Tracking body composition — not just weight
Prioritize high-quality protein
Aim for 0.8 to 1.2 grams of protein per pound of lean body mass per day. This means that if your lean body mass is 150 pounds, you should consume between 120 and 180 grams of protein per day. Spread that consumption out across the day in several small meals.
For reference:
— 6 ounces of lean meat, such a chicken breast, turkey, or pork contains about 40 to 50 grams of protein
— A 3.5-ounce serving of cod, tuna or salmon contains about 30 grams of protein
— A single large egg contains about 6 to 7 grams of protein
— 1 cup of 0%-fat Greek yogurt or cottage cheese contains about 17 to 24 grams of protein
Adding more of these protein sources to your diet can help you maintain muscle mass as you lose weight.
Protein content per serving
| Food | Serving Size | Protein Content |
| Chicken Breast | 6 oz | 45g — 50g |
| Salmon/Tuna | 3.5 oz | 30g |
| Greek Yogurt (0% Fat) | 1 cup | 17g — 24g |
| Large Egg | 1 egg | 6g — 7g |
[READ: Exercising on GLP-1s: How to Stay Safe and Healthy]
Eat enough calories
Fast weight loss isn’t healthy weight loss.
“You should be eating adequate calories to maintain a stable weight loss of not more than 1 to 2 pounds per week,” says Tribble. Rapid “crashing” increases the risk of muscle atrophy and metabolic slowdown, which often leads to “rebound” weight gain once the medication is stopped.
This is important because while some muscle loss is likely as you lose weight, “losing weight at a slower rate will mitigate most of those losses,” Tribble adds.
Losing weight too quickly can also result in another downside: Patients who are taking GLP-1s who’ve experienced significant weight loss and muscle atrophy can end up with loose skin. Golpanian says these individuals may end up in his office asking for help to remove this excess skin. Loose skin can be removed, but it requires surgery. Working to maintain as much muscle mass as possible while you’re losing weight can reduce the volume of loose skin that develops with weight loss.
Incorporate resistance training
To keep your metabolism firing, you must signal to your body that your muscles are still needed.
Golpanian emphasizes resistance or strength training two or three times a week for a minimum of 30 minutes to help stimulate muscle growth. Resistance training means “anything using your own body weight or added weight,” he says. “It’s not stretching; it’s not cardio. It’s getting your muscles to work.”
Examples of resistance training include:
— Planks
— Squats
— Lunges
— Push-ups
— Arm raises
— Leg raises
— Wall-sits
— Kettlebell swings
— Weight machine exercises
— Lifting free weights
In fact, doing more cardiovascular exercise burns lots of calories, which can theoretically make you lose weight faster. But it can also lead to more muscle loss as your body breaks down muscle to make energy. Therefore, it’s critical that your exercise plan includes weight training, resistance training and other muscle-building activities.
Track body composition — not just weight
A number on the scale doesn’t tell the whole story. Consider a DEXA scan for precise lean mass measurements or a bioimpedance scale at home to monitor whether your weight loss is coming from fat or muscle.
Talk with your health care provider about getting a dual-energy X-ray absorptiometry scan — known as a DEXA scan — which will give you a precise measurement of lean body mass, and see if you can repeat that test on a regular basis to track where your weight loss is coming from.
Bioimpedance scales, which use a mild electrical current to assess fat, muscle and water weight, can also help you determine whether your weight loss has come from fat or muscle loss. Some at-home scales have a body composition mode that makes tracking this easier.
[READ: What to Eat — and Avoid — on GLP-1 Weight Loss Medications]
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GLP-1 Muscle Loss: How to Prevent Muscle Wasting on Wegovy and Other GLP-1s originally appeared on usnews.com