Ozempic vs Wegovy
4 min readBy Dr Chad Okay
Ozempic and Wegovy are both semaglutide. Same molecule. Different brand, different dose ladder, different licensed indication. Ozempic is licensed for type 2 diabetes (up to 2 mg weekly). Wegovy is licensed for weight management (up to 2.4 mg weekly). The pens look similar but are not interchangeable. If you have diabetes, Ozempic. If your reason is weight loss alone in the UK, Wegovy.
If you've been confused by Ozempic vs Wegovy, you're in good company. They're the same drug at different doses with different labels. Here's a clean breakdown of what differs and what doesn't.
What's identical
- Active ingredient: semaglutide.
- Manufacturer: Novo Nordisk.
- Mechanism: GLP-1 receptor agonist. Slows gastric emptying, reduces appetite, lowers blood sugar.
- Side effect profile: nausea, constipation, reflux, fatigue.
- Pen design: very similar; both are weekly self-injection pens.
- Storage: refrigerated unopened, room temperature once in use.
What differs
| Ozempic | Wegovy | |
|---|---|---|
| Licensed for | Type 2 diabetes; CV risk reduction in T2D | Weight management (BMI ≥30 or ≥27 with comorbidity) |
| Maximum dose | 2 mg weekly | 2.4 mg weekly |
| Dose ladder steps | 0.25 → 0.5 → 1 → 2 mg | 0.25 → 0.5 → 1 → 1.7 → 2.4 mg |
| Time to maintenance | 16 weeks | 16-20 weeks |
| Average weight loss at 12 months | 9-12% (1-2 mg) | 15% (2.4 mg) |
| NHS access | Routine for T2D not controlled on metformin | Specialist Tier 3 services only (NICE TA875) |
| UK monthly cost (private) | £200-300 | £200-300 |
Why two brands for the same drug?
Regulatory licensing. To get approved for weight loss, the drug needed dedicated trials in a non-diabetic obese population (the STEP trials). Once those completed, Novo Nordisk launched the higher-dose version under a separate brand. This gives clearer prescribing pathways, separate pricing in some markets, and avoids confusion when prescribers and patients are talking about diabetes vs weight management goals.
Which to ask for
- Type 2 diabetes (with or without obesity): Ozempic is the standard NHS pathway. Wegovy might be considered later if weight is the primary issue.
- Obesity without diabetes (UK): Wegovy is the licensed option. NHS access is restricted to Tier 3 services; most UK users currently pay privately.
- Pre-diabetes plus obesity: NICE recommends Wegovy via specialist services. Some private clinics will prescribe directly.
- If supply of one is unstable: switching between Ozempic and Wegovy is sometimes possible with prescriber support, since the drug is the same. Dose conversion isn't 1:1 because the dose ladders are different.
Side effects compared
- Nausea: more common at higher Wegovy doses (~44% on 2.4 mg) than at 1 mg Ozempic (~20%). Usually settles in 4-8 weeks.
- Constipation: Wegovy 2.4 mg ~24% (STEP 1-3 pooled, Wharton 2022), Ozempic 1 mg ~6% (SUSTAIN/PIONEER pooled, Aroda 2023).
- Diarrhoea: Wegovy 2.4 mg ~30%, Ozempic 1 mg ~10%.
- Vomiting: rare at therapeutic doses on either, peak during titration.
- Pancreatitis, gallstones, severe gastroparesis: rare on both, well-recognised. Persistent severe abdominal pain warrants stopping.
- Hair shedding: reported on both, more common at higher doses, usually reversible with weight stabilisation.
What you can't get on either
- Tirzepatide (Mounjaro/Zepbound), different molecule, different drug class (dual GLP-1 + GIP), produces more weight loss in head-to-head trials.
- Compounded semaglutide from US-style mid-tier pharmacies, quality, sterility, and dose accuracy are all unverifiable. Avoid.
- Daily injection equivalents (Saxenda, Victoza), those are liraglutide, an older shorter-acting GLP-1.
- Oral semaglutide: Rybelsus (3, 7, 14 mg) is licensed for type 2 diabetes only. The Wegovy pill, once-daily oral semaglutide 25 mg, was FDA-approved for chronic weight management on 22 December 2025 (mean weight loss ~16.6% in OASIS-4); UK availability lags.
Common questions
- Are Ozempic and Wegovy interchangeable?
- The drug is the same, the dose ladders aren't. You can switch under prescriber supervision but not just swap pens. The 2 mg Ozempic dose is closer to the 2.4 mg Wegovy dose than to the lower Wegovy doses, so a direct conversion isn't precise.
- Will I lose more weight on Wegovy than Ozempic?
- On average yes, because the licensed maximum dose is higher. STEP 1 trial: 15% average weight loss on Wegovy 2.4 mg at 68 weeks. SUSTAIN trials of Ozempic 1 mg at similar timepoints: about 6%. Ozempic 2 mg sits in between. The trade-off is more side effects at the higher dose.
- Can I get Wegovy on the NHS?
- In principle yes, in practice rationed. NICE TA875 recommends Wegovy for adults with BMI ≥35 plus a weight-related condition, accessed through specialist Tier 3 weight-management services. The number of those services is limited, so most UK users currently pay privately at £200-300/month.
- What if I have both diabetes and obesity?
- Ozempic is usually first-line on the NHS. If your BMI qualifies and weight is the bigger driver of risk, Wegovy can sometimes be argued for, but pathway depends on local services. Mounjaro/tirzepatide is increasingly considered too. A diabetologist or specialist weight clinic is the right starting point.