Ozempic vs Wegovy

Dr Chad OkayFounder, Suna Health

5 min read. Updated .

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

OzempicWegovy
Licensed forType 2 diabetes; CV risk reduction in T2DWeight management (licence: BMI ≥30, or ≥27 with a weight-related condition)
Maximum dose2 mg weekly2.4 mg weekly
Dose ladder steps0.25 → 0.5 → 1 → 2 mg0.25 → 0.5 → 1 → 1.7 → 2.4 mg
Time to maintenance16 weeks16-20 weeks
Average weight loss at 12 months~6-7% (1-2 mg)15% (2.4 mg)
NHS accessRoutine for T2D not controlled on metforminThrough specialist weight-management services, for a maximum of 2 years (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 the people they prescribe for are talking about diabetes vs weight management goals.

Which one fits which situation

  • 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 the higher Wegovy dose (~44% on 2.4 mg, STEP 1-3 pooled, Wharton 2022) than on Ozempic (~15-19% across the SUSTAIN programme, Aroda 2023). Typically mild to moderate and eases after the first weeks at each dose step.
  • 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% (Wharton 2022), Ozempic ~10-13% (Aroda 2023).
  • Vomiting: not rare. About 24% on Wegovy 2.4 mg versus 6% on placebo in the pooled STEP trials (Wharton 2022), and around 7% across the SUSTAIN trials. It clusters during dose escalation.
  • Pancreatitis, gallstones, severe gastroparesis: uncommon on both, well-recognised. Severe, persistent abdominal pain needs same-day medical assessment, not a wait-and-see approach (see below).
  • Hair shedding: listed in the Wegovy prescribing information and reported on both. It is thought to track rapid weight loss itself rather than the drug, and usually settles as weight stabilises.

If something feels wrong

This article is about comfort and everyday patterns, 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.

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% among participants who stayed on treatment 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 semaglutide for weight management only within a specialist weight-management service, for a maximum of 2 years, for adults with at least one weight-related condition and a BMI of 35 or more, or 30 to 34.9 if they meet the criteria for specialist referral. NICE applies lower BMI thresholds (usually reduced by 2.5) for people from South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean family backgrounds. The number of those services is limited, so most UK users currently pay privately. Note the licence is broader than NHS access: the drug itself is licensed from BMI 30, or 27 with a weight-related condition, which is why private prescribing reaches people the NHS pathway does not.
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.

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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