How to lose fat on Ozempic or Wegovy

Ozempic and Wegovy are the same drug, semaglutide. Wegovy is the version approved for weight loss, and Ozempic is approved for type 2 diabetes. In the main weight loss trial, 1,961 adults on a weekly 2.4 mg shot lost 14.9% of their weight in 68 weeks, against 2.4% on placebo. To make that loss mostly fat, eat protein first, lift weights and keep the habits when you stop.

Ozempic or Wegovy: what’s the difference?

The drug inside is the same. The doses and the approvals differ, and your prescriber chooses.

How semaglutide works

Semaglutide copies GLP-1, a hormone your gut releases when you eat. It acts on the parts of your brain that control appetite, so you feel less hungry and full sooner, and it slows how fast your stomach empties. It stays in the blood about a week, which is why it’s a weekly shot, and it takes five to seven weeks to leave your body after the last dose.

The drug is like a strong tailwind. It moves you faster, and you still do the steering.

What the trials found

How much of the loss is muscle?

In STEP 1, 140 people had DEXA scans. On semaglutide their fat mass fell 19.3%, their deep belly fat 27.4% and their lean mass 9.7%. Of the weight lost, the 2025 US nutrition advisory counts about 62% as fat and 38% as lean mass. Lean mass includes water and organs, so muscle is only part of it.

A 2026 study is more hopeful. In SEMALEAN, 106 adults with severe obesity took semaglutide for a year. Their lean mass fell about 7 pounds (3 kg) by month seven and then held steady, and their grip strength rose by about 9 pounds (4 kg).

How to keep muscle on it

• Protein first. Make every meal, however small, start with protein: eggs, Greek yogurt, fish, chicken, tofu, a protein shake.
• Lift. The 2025 advisory suggests strength training at least three times a week, plus at least 150 minutes of moderate cardio.
• Watch the pace with your prescriber. In athletes, faster loss kept less lean mass. If you’re losing much more than 1% of your weight a week, bring it up.
• Track a lift and your waist, not only the scale. See am I losing fat or muscle.

What happens when you stop

In the STEP 1 extension, 327 people who stopped semaglutide after 68 weeks had lost 17.3% of their weight. A year later they were only 5.6% below where they started, and most of their health gains had faded. In STEP 4, people switched to a placebo after 20 weeks regained 6.9% over the next 48 weeks, while those who stayed on it lost another 7.9%. More in what happens when you stop taking Ozempic.

The side effects that matter

The label also warns of pancreatitis, low blood sugar when taken with insulin or some diabetes pills, kidney injury from losing fluid, a faster heart rate and allergic reactions. It carries a boxed warning because semaglutide caused thyroid tumors in rodents, so people with a personal or family history of medullary thyroid cancer or MEN 2 shouldn’t take it. Tell your surgeon before any procedure that needs anesthesia. The Wegovy label says it may harm an unborn baby and advises stopping it at least two months before a planned pregnancy, because it lasts so long in the body. Plan that with your doctor.