Wegovy and Ozempic contain exactly the same active ingredient, semaglutide, manufactured by the same company, Novo Nordisk. So why are they different products? What distinguishes them? And which one should you be taking for weight loss?
The one-sentence answer
Ozempic is licensed in the UK exclusively for type 2 diabetes. Wegovy is licensed for weight management. In the UK, Ozempic should not be prescribed for weight loss in patients without type 2 diabetes. This is off-label prescribing that previously contributed to medication shortages affecting diabetic patients who depended on it.
Same molecule, different doses, different indications
Both contain semaglutide, a GLP-1 receptor agonist. Both are once-weekly subcutaneous injections. The mechanism is identical. The molecule is identical. What differs is the licensed dose and indication.
Ozempic doses (licensed for type 2 diabetes): starts 0.25mg weekly, escalating to 0.5mg, 1mg, with a maximum of 2mg in some patients.
Wegovy doses (licensed for weight management): starts 0.25mg weekly, escalating through 0.5mg, 1mg, 1.7mg, to a maximum maintenance dose of 2.4mg.
The higher maintenance dose of Wegovy (2.4mg vs Ozempic's typical clinical maximum of 1mg) is the primary reason Wegovy produces greater weight loss. More semaglutide means more GLP-1 receptor activation and greater appetite suppression. At comparable doses, there is no meaningful difference between the two products, semaglutide is semaglutide. The licensed dose, not the brand name, is what drives efficacy.
Why was Ozempic used for weight loss at all?
Before Wegovy was available in the UK, some clinicians prescribed Ozempic off-label for weight loss after observing significant weight loss in their diabetic patients. Social media amplification, particularly in the US, significantly increased demand. This contributed to major Ozempic shortages in 2022 to 2023, leaving diabetic patients unable to obtain their medication. The MHRA and NHS subsequently advised that Ozempic should be reserved for its licensed indication. Wegovy, developed and licensed specifically for weight management at 2.4mg, is now the appropriate choice.
The clinical evidence for weight loss
STEP-1 trial (Wegovy, semaglutide 2.4mg, NEJM 2021, Wilding JPH et al): average weight loss 14.9% of starting body weight over 68 weeks in adults without diabetes.
Because Wegovy is licensed at a higher dose than Ozempic's typical diabetes dosing, it produces substantially greater weight loss. The dose-response relationship for semaglutide is well established, higher doses produce greater appetite suppression and greater weight reduction. The 2.4mg maintenance dose used in Wegovy is the dose at which the clinical weight loss evidence was generated.
Cardiovascular evidence
Ozempic: SUSTAIN-6 trial demonstrated cardiovascular benefit in patients with type 2 diabetes and high cardiovascular risk.
Wegovy: SELECT trial (Lincoff AM et al, NEJM 2023) demonstrated a 20% reduction in major adverse cardiovascular events: heart attack, stroke, and cardiovascular death. In patients with pre-existing cardiovascular disease and obesity or overweight (BMI ≥27) without diabetes. The MHRA licensed Wegovy specifically for cardiovascular risk reduction in this population, the first weight loss medication in the UK with this licensed indication.
Can I use Ozempic instead of Wegovy?
In the UK: not appropriately. Without a type 2 diabetes diagnosis, Ozempic is not licensed for you and should not be prescribed for weight loss. Being offered Ozempic for weight loss without a diabetes diagnosis by a private provider is a red flag, the prescribing is off-label, the dose is lower than the evidence for weight management supports, and it diverts supply from diabetic patients.
Which is right for me?
No type 2 diabetes, seeking weight loss: Wegovy is the appropriate licensed option.
Type 2 diabetes, seeking weight loss: either may be appropriate depending on your clinical picture. Wegovy at 2.4mg produces greater weight loss; Ozempic provides proven glycaemic benefit at established diabetes doses. Your prescribing pharmacist or diabetes team will advise.
Cardiovascular disease with obesity or overweight: Wegovy's SELECT trial evidence gives it a specific licensed advantage that Ozempic does not share for non-diabetic patients with cardiovascular disease.
How does Mounjaro compare?
Mounjaro (tirzepatide) produces greater average weight loss than Wegovy in head-to-head clinical evidence. SURMOUNT-5 (Aronne LJ et al, NEJM 2025, n=751), the first direct RCT comparing tirzepatide and semaglutide in non-diabetic patients with obesity, showed tirzepatide produced 20.2% weight loss vs 13.7% for semaglutide at maximum tolerated doses over 72 weeks. For patients without a specific reason to prefer semaglutide, such as established cardiovascular disease where Wegovy's SELECT data applies. Mounjaro is currently the most potent licensed weight loss option in the UK.
"Wegovy and Ozempic are the same molecule at different doses for different licensed indications. The weight loss evidence was generated at Wegovy's 2.4mg dose, which is why Wegovy, not Ozempic, is the appropriate choice for weight management in the UK."
- If you have been offered Ozempic for weight loss without a type 2 diabetes diagnosis, discuss whether Wegovy is more appropriate
- If you have type 2 diabetes and are unsure whether Ozempic or Wegovy best suits your clinical situation
- If you have cardiovascular disease. Wegovy's SELECT evidence is worth discussing specifically
- If you are considering switching between medications
References
- Wilding JPH et al. N Engl J Med 2021;384:989 to 1002 (STEP-1).
- Lincoff AM et al. N Engl J Med 2023;389:2221 to 2232 (SELECT).
- Frías JP et al. N Engl J Med 2021;385:503 to 515 (SURPASS-2).
- Aronne LJ et al. N Engl J Med 2025;393:26 to 36 (SURMOUNT-5).
- MHRA Summary of Product Characteristics: Wegovy and Ozempic, 2024.
Reviewed by Jimah Alsaai MPharm, GPhC 2232652, Superintendent Pharmacist, Solira.