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Use & how it works

How do GLP-1 medications work?

GLP-1 medications mimic the body's own hormone GLP-1 (glucagon-like peptide-1), which is released in the gut after eating. As a result, appetite decreases, you feel full sooner and for longer, and your blood sugar stays more stable. These are prescription-only medicines; a doctor assesses whether they are suitable for you, and they are supplied through a doctor and a pharmacy.

What is GLP-1?

GLP-1 is a hormone that your gut releases after a meal. Among other things, it drives the release of insulin and sends a satiety signal to the brain. The modern medications for obesity and type 2 diabetes are engineered versions of this hormone, also known as GLP-1 receptor agonists. Well-known active substances are semaglutide (found in Ozempic, Wegovy and Rybelsus, among others), tirzepatide (Mounjaro) and liraglutide (Saxenda).

How does it reduce appetite?

These medications act in several places at once:

  • Appetite suppression: they influence the satiety centre in the brain, which reduces the feeling of hunger.
  • Slower gastric emptying: food stays in the stomach longer, so you feel full sooner and stay satiated longer.
  • More stable blood sugar: insulin release is stimulated when blood sugar rises, and glucagon release is suppressed.

With less hunger and earlier satiety, you typically eat less, which can contribute to weight loss. The exact effects and how they work can vary from person to person.

Difference between semaglutide and tirzepatide

Semaglutide and liraglutide act only on the GLP-1 receptor. Tirzepatide also acts on the GIP receptor (glucose-dependent insulinotropic polypeptide), a second gut hormone. Because of this dual action, tirzepatide is sometimes viewed differently from the pure GLP-1 medications. Which active substance is appropriate depends on your situation and is a judgement the doctor makes. You can read a factual comparison on Ozempic or Mounjaro.

Lifestyle is still needed

GLP-1 medications are not a substitute for healthy eating and exercise. In the studies and patient leaflets, they are used alongside an adjusted lifestyle, not instead of one. Nutrition, exercise and guidance remain a fixed part of the treatment.

This page provides general, factual information and is not medical advice. Only a doctor can assess whether a GLP-1 medication is suitable for you.

Frequently asked questions

Are GLP-1 medications available without a prescription?
No. GLP-1 medications such as Ozempic, Wegovy, Mounjaro and Saxenda are prescription-only. A doctor first assesses whether they are suitable; they are supplied through a doctor and a pharmacy.
Do GLP-1 medications work without dieting?
In studies the medications were always combined with an adjusted lifestyle. Healthy eating and exercise remain necessary; the medication supports appetite regulation but does not replace lifestyle.
What is the difference between GLP-1 and GIP?
GLP-1 and GIP are both gut hormones that influence blood sugar and appetite. Semaglutide and liraglutide act only on GLP-1; tirzepatide acts on both GLP-1 and GIP.

Official sources on this topic

Independent, authoritative information from official bodies:

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