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How does semaglutide work for weight loss?

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on Feb 11, 2025.

Official Answer by Drugs.com

You will lose weight over the long-term with semaglutide because you will eat less, and feel fuller when you do eat. Semaglutide does this by targeting an area in the brain (called GLP-1 receptors) that help to regulate your appetite and how much you eat. It closely mimics a natural hormone in the body called incretin, which is made primarily in our digestive tract.

Semaglutide is used as a long-term weight loss treatment in addition to a healthy diet and exercise to help promote weight loss. Semaglutide (Wegovy and Ozempic) are also approved to help protect the heart in patients with heart disease.

In addition, Ozempic is approved is as treatment for type 2 diabetes to control blood sugar (glucose) levels and to reduce the risk of worsening kidney disease, kidney failure (end-stage kidney disease) and cardiovascular death in adults with type 2 diabetes and chronic kidney disease.

What is the mechanism of action of semaglutide?

Semaglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist and occupies the GLP-1 receptor in the brain that regulates appetite.

It should not be used with other semaglutide-containing products (such as Ozempic, Rybelsus) or other GLP-1 receptor agonist medicines.

Semaglutide helps people to lose weight by:

Who can use semaglutide for weight loss?

Semaglutide (Wegovy) is used, in addition to a low-calorie diet and increased physical exercise:

Other prescription drugs that also contain semaglutide are Ozempic (injection) or Rybelsus (oral tablets). These brands are not specifically approved for weight loss, but can lead to weight loss when used for their indications.

Related questions

How long does semaglutide take to work?

You may see some weight loss in the 4 weeks of semaglutide treatment, but the full effect can take several months. After 68 weeks, adults lost an average of about 35 lbs (15.9 kg), or 15% of their weight, and these results were sustained at 2 years.

Your doctor will slowly increase your dose when you start treatment to help lessen stomach side effects like nausea and diarrhea. It typically takes about 17 weeks to reach your final maintenance dose of semaglutide.

This is not all the information you need to know about semaglutide (Wegovy) for safe and effective use and does not take the place of your doctor’s directions. Review the full product information and discuss this information and any questions you have with your doctor or other health care provider.

References

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Both tirzepatide and semaglutide are prescription medicines used with diet and exercise to treat people with type 2 diabetes or to help people lose and maintain weight loss. Tirzepatide is also approved by the FDA to treat moderate to severe obstructive sleep apnea (OSA) in adults with obesity, while semaglutide is approved to reduce the risk of serious heart problems and to help reduce the risk of worsening kidney disease.

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Why am I not losing weight on Ozempic?

Although Ozempic is not FDA-approved for weight loss, over 86% of people lose at least 5% of their body weight in trials that have studied semaglutide, the active ingredient of Ozempic. But the same clinical trials also show that just under 14% don’t lose weight, and some may even gain weight. Continue reading

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