Ozempic

Also called semaglutide injection, Ozempic pen.

Dr Chad OkayFounder, Suna Health

4 min read. Updated .

Ozempic is a brand name for semaglutide, a weekly injection licensed for type 2 diabetes. It is a GLP-1 receptor agonist, meaning it mimics a gut hormone that lowers blood sugar, slows stomach emptying, and reduces appetite. The same drug at a higher dose is sold as Wegovy for weight loss. Ozempic is not licensed for weight loss in the UK.

What Ozempic actually is

Ozempic is the brand name Novo Nordisk uses for semaglutide injections at doses of 0.25 mg, 0.5 mg, 1 mg, and 2 mg, taken once a week. The active drug, semaglutide, is the same as in Wegovy and in oral Rybelsus, but at different doses and with different licensed uses.

How it works

Semaglutide mimics GLP-1, a hormone your gut releases after meals. GLP-1 prompts the pancreas to release insulin, slows the rate at which food leaves the stomach, and signals fullness to the brain. The combined effect lowers blood sugar after meals and reduces overall food intake. The weight-loss effect is largely a downstream consequence of eating less for longer.

What it is licensed for

  • Type 2 diabetes in adults whose blood sugar is not controlled on metformin or other oral medications.
  • Reducing the risk of major cardiovascular events in adults with type 2 diabetes and existing heart disease.
  • Not licensed for weight loss in the UK or US. The same molecule at a higher 2.4 mg weekly dose is licensed for weight loss as Wegovy.

Common side effects

  • Nausea, especially in the first 4 to 8 weeks. Usually settles as the body adjusts.
  • Constipation. Slowed gut transit is part of the mechanism. Pooled SUSTAIN/PIONEER trial data put the rate at around 6% on diabetes doses of semaglutide (Aroda 2023, 5.8-6.5% across subcutaneous and oral semaglutide), much lower than higher-dose Wegovy 2.4 mg (around 23% in STEP 1, Wilding 2021; 24.2% pooled across STEP 1-3, Wharton 2022).
  • Reflux and burping. Food sits longer in the stomach and pressure rises.
  • Loss of appetite. The intended effect, but it can mean missed meals and dehydration if not managed.
  • Tiredness and brain fog in early weeks, often linked to lower calorie intake.
  • Rare but serious: pancreatitis, gallstones, and severe gastroparesis. Sharp, persistent abdominal pain needs a doctor the same day, not a wait-and-see approach (see below).

If something feels wrong

This entry is reference information, not medical guidance. Your doctor and pharmacist know you and your medicine; if anything about how you feel worries you, speak to them promptly, and if you ever feel seriously unwell, treat it as an emergency. The medicine's own patient information leaflet carries the important safety information and is worth reading in full.

Ozempic vs Wegovy vs Mounjaro

Ozempic and Wegovy are the same drug, semaglutide, at different licensed doses and indications. Mounjaro is tirzepatide, a different molecule that activates both GLP-1 and GIP receptors and tends to produce slightly more weight loss in head-to-head trials. Access in the UK depends on the indication: type 2 diabetes runs through the NHS pathway, while weight management means Wegovy or Mounjaro, either under NICE criteria or by private prescription.

Common questions

Is Ozempic the same as Wegovy?
Same drug, semaglutide. Different doses and different licensed uses. Ozempic goes up to 2 mg weekly for diabetes. Wegovy goes up to 2.4 mg weekly for weight loss. The pens look similar but are not interchangeable.
Why does Ozempic cause constipation?
Slowing gut transit is part of how the drug works. It keeps food in the stomach and small intestine longer, which improves blood sugar but also dries out stools by the time they reach the colon. Hydration, fibre and movement help. Dose decisions sit with your prescriber.
Will I gain weight back if I stop?
Most people regain a substantial portion of lost weight within a year of stopping. The drug works by lowering appetite and slowing eating. Once those effects wear off, eating returns to baseline. Long-term use is the model the trials assumed, similar to other chronic-condition medications.
Can I drink alcohol on Ozempic?
Small amounts are usually fine. Heavy drinking is risky because alcohol can drop blood sugar and irritate the stomach, both of which compound the drug effects. Many users report alcohol no longer feels enjoyable, which is itself an emerging research area.

Sources

Written by Dr Chad Okay. Contributor: Dr Parisah Hussain, MBChB, BSc (Hons), DRCOG, MRCGP. Last updated 17 September 2026. From Digests.

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