Semaglutide
Semaglutide is a GLP-1 receptor agonist used for type 2 diabetes and weight loss, sold as Rybelsus, Ozempic and Wegovy — the same active drug in different forms.
Semaglutide is a medication used to treat type 2 diabetes and, under different branding, for long-term weight management. It belongs to a class of drugs called GLP-1 receptor agonists, which lower blood sugar and reduce appetite. Sold as Rybelsus (oral tablet), Ozempic (injection for diabetes) and Wegovy (injection for weight loss), it is the same active drug across all three — and in every form it is prescription-only.
Semaglutide has become one of the best-known medicines of recent years because of its effect on weight. Understanding what it is, how it works and who it suits helps separate the science from the hype.
What semaglutide does
Semaglutide mimics a natural hormone, glucagon-like peptide-1 (GLP-1). It lowers blood sugar in a glucose-dependent way — increasing insulin secretion when blood sugar is high and reducing the liver's glucose output by lowering glucagon. At the same time, it slows stomach emptying and curbs appetite, which is why it also produces weight loss.
Medical uses
Semaglutide has two main approved roles:
| Use | Brand / form | Notes |
|---|---|---|
| Type 2 diabetes | Rybelsus (oral), Ozempic (injection) | Improves blood sugar and lowers A1C |
| Weight management | Wegovy (injection) | For obesity (BMI ≥ 30) or overweight (BMI ≥ 27) with a related condition |
For type 2 diabetes, it is used alongside diet and exercise to control blood sugar. For weight loss, the Wegovy form at a typical dose of 2.4 mg weekly has shown significant results — participants lost up to around 15% of their body weight over 68 weeks when combined with lifestyle changes.
Side effects and risks
The most common side effects are gastrointestinal — nausea, vomiting, diarrhoea and constipation — usually most pronounced when starting or increasing the dose and easing over time. More serious but rarer risks can include pancreatitis and gallbladder problems, which is part of why medical supervision matters. Starting low and increasing the dose gradually is the standard way to keep side effects manageable.
Contraindications and who should be cautious
Semaglutide is not suitable for everyone. It is contraindicated in people with a personal or family history of certain thyroid cancers (medullary thyroid carcinoma) or the condition MEN 2, and caution is needed in those with a history of pancreatitis or significant gastrointestinal disease. These considerations are exactly why a clinician must assess suitability before prescribing.
Oral versus injectable forms
Because the same drug comes in a daily tablet (Rybelsus) and weekly injections (Ozempic, Wegovy), people often ask how they compare and how to move between them. The oral and injectable forms are dosed differently and are not interchangeable milligram-for-milligram, as we explain in our article on 14 mg Rybelsus to Wegovy. For a broader external reference covering this drug and its forms, see this overview of semaglutide. For how well the tablet works for weight loss specifically, see whether Rybelsus is a good weight loss pill.
The takeaway
Semaglutide is a powerful, well-studied medication for type 2 diabetes and weight management, but it is a prescription medicine with real side effects and contraindications — not a casual purchase. It works best alongside diet and lifestyle change and under medical supervision. For the full picture of this drug family, see our guide to Rybelsus and semaglutide.