Zepbound can drive dramatic weight loss, but the number on the scale hides a detail that decides whether the results last: how much of what you lose is fat versus muscle. If you are on Zepbound, or thinking about it, the smartest move you can make is to train in a way that protects your lean mass. This is a plain-English guide to what Zepbound is, what the trial data actually shows, and how to stay consistent with the strength work that keeps your results. It is not medical advice, and Zepbound is prescription-only.
What Zepbound is
Zepbound is the brand name for tirzepatide, made by Eli Lilly, approved by the FDA for chronic weight management in adults with obesity or overweight who have a related health condition, alongside a reduced-calorie diet and increased activity. It is the same active molecule sold under a different brand for type-2 diabetes, but Zepbound is the weight-management version. It is a once-weekly injection and works as a dual GIP and GLP-1 receptor agonist.
How it works
Tirzepatide imitates two hormones your gut naturally releases after eating. By activating both the GIP and GLP-1 receptors, it slows gastric emptying, helps regulate blood sugar and insulin, and reduces appetite signaling in the brain. In everyday terms, you feel full faster and stay satisfied longer, so you eat less without white-knuckling it. Sustained lower intake is what produces the weight loss seen in the trials.
The evidence
The pivotal trial was SURMOUNT-1, published in the New England Journal of Medicine. According to Eli Lilly's summary of the results, adults with obesity or overweight lost between 16.0% and 22.5% of their body weight on average over 72 weeks depending on dose, versus about 3.1% on placebo, with the top dose averaging roughly 22.5% (about 52 pounds). That places tirzepatide among the most effective weight-management medicines studied to date, which is exactly why muscle preservation deserves attention.
The muscle catch
When weight comes off this fast, a meaningful share of the loss can be lean muscle, not only fat. That is a problem for three reasons: muscle powers your metabolism, it keeps you strong and mobile, and losing it makes weight easier to regain, and regain after stopping is the field's number-one challenge. The evidence-backed defense is consistent: resistance training plus enough protein is the best-known way to keep muscle while you lose fat. Zepbound manages your appetite; keeping your strength is the part you train for.
How Cadoo helps
The gap is never knowing you should lift: it is doing it week after week while your appetite and energy are down. Cadoo is a fitness app that closes that gap by making it a game: you commit money with friends toward hitting a fitness goal, so each workout is a real commitment, not a maybe. For supported movements like pushups and squats, your phone's camera counts your reps and scores your form, so the effort is verified, while steps and distance sync from Apple Health or Google Health Connect. Recurring challenges keep you accountable through the quiet weeks when muscle-preserving habits usually slip. To be clear, Cadoo does nothing to how Zepbound works pharmacologically: its only role is helping you stay consistent with the movement that protects your results.
This article is for general information only and is not medical advice. Zepbound is prescription-only; individual results vary; talk to your doctor or clinician before starting, stopping, or changing any medication or exercise program. Cadoo is not affiliated with, endorsed by, or sponsored by Eli Lilly or any manufacturer. Zepbound and tirzepatide are trademarks of their respective owners, referenced here editorially.
Frequently asked questions
Can you exercise on Zepbound?
For most people, yes, and it is built into the approved use, which pairs Zepbound with increased physical activity. Strength training is especially valuable because it protects the muscle you can lose during rapid weight loss. Since appetite and energy may be lower, ease in, stay hydrated, and clear any new program with your doctor. This is general information, not medical advice.
Does Zepbound cause muscle loss?
Fast weight loss on any GLP-1-class medication can include a meaningful amount of lean muscle, not just fat, and Zepbound's strong results make this worth planning for. The best-supported countermeasure is resistance training two to three times a week plus adequate protein, which the clinical consensus links to preserving muscle while losing fat.
What workouts are best on Zepbound?
Lead with resistance training, bodyweight or weighted, because that is what preserves muscle, then add walking or light cardio for overall health. Cadoo can camera-verify reps for supported strength movements and pull steps from Apple Health or Google Health Connect, so you can turn both into an accountable, money-backed challenge with friends.
How do I avoid regaining weight after Zepbound?
Regain after stopping a GLP-1 is the field's biggest challenge, and preserved muscle plus a durable exercise habit are your best defenses. Building consistent strength training while you are on the drug, the accountability Cadoo is designed to create, helps the habit outlast the prescription. Discuss any changes with your doctor; this is not medical advice.
