Is Mounjaro better than Ozempic for diabetes?

On HbA1c reduction and weight loss, yes, SURPASS-2 showed clear advantages. On established cardiovascular outcomes data, Ozempic still leads. For most people newly starting GLP-1 therapy without prior CV disease, Mounjaro is the more efficacious choice.

Should I switch from Ozempic to Mounjaro?

If your HbA1c and weight goals are met on Ozempic, no reason to switch. If you're at 1-2 mg Ozempic and not at target, switching to Mounjaro under prescriber supervision is reasonable. Don't self-switch; dose conversions aren't 1:1.

Can Ozempic be used off-label for weight loss?

Some private clinics do this in the UK. NHS doesn't. Off-label use raises ethical and supply concerns, using a diabetes drug for weight loss can contribute to shortages for diabetic patients. Wegovy or Mounjaro for licensed weight management is the cleaner route.

What about Mounjaro vs Wegovy for weight loss?

See our Mounjaro vs Wegovy comparison. Short version: SURMOUNT-5 head-to-head showed Mounjaro 20.2% vs Wegovy 13.7% weight loss at 72 weeks. Mounjaro wins on weight loss; Wegovy has more years of safety data.

Mounjaro vs Ozempic

3 min readUpdated 2026-04-26By Dr Chad Okay

Both are weekly injections used for type 2 diabetes (and, in the UK, weight management). Mounjaro is tirzepatide (dual GLP-1 + GIP); Ozempic is semaglutide (GLP-1 only). Mounjaro produces stronger blood sugar control AND more weight loss in head-to-head trials. Ozempic has more cardiovascular outcomes evidence. For type 2 diabetes alone, both are excellent; Mounjaro slightly edges ahead on efficacy, Ozempic on track record.

If you're being prescribed either Mounjaro or Ozempic, the conversation has shifted in 2024-2025. Tirzepatide has matured into a real first-line contender. Here's how to think about the choice.

Head-to-head: SURPASS-2

The SURPASS-2 trial randomised 1,879 adults with type 2 diabetes inadequately controlled on metformin to either tirzepatide (5, 10, or 15 mg weekly) or semaglutide 1 mg weekly. After 40 weeks: HbA1c reduction of 2.0-2.3% on tirzepatide vs 1.9% on semaglutide. Weight loss: 7.6-11.2 kg on tirzepatide vs 5.7 kg on semaglutide. Tirzepatide won on both outcomes, with the largest gaps at the 10 mg and 15 mg doses.

What's different

	Mounjaro	Ozempic
Active drug	Tirzepatide	Semaglutide
Drug class	Dual GLP-1 + GIP agonist	GLP-1 agonist
Manufacturer	Eli Lilly	Novo Nordisk
Maximum dose (diabetes)	15 mg weekly	2 mg weekly
HbA1c reduction (max dose)	~2.3%	~1.8%
Weight loss in T2D at 40 weeks	7-11 kg	~6 kg
Cardiovascular outcomes data	SURPASS-CVOT (2025) non-inferior vs dulaglutide	SUSTAIN-6 (positive)
UK NHS for diabetes	Increasingly used	Long-established

What's the same

Schedule: both weekly injections.
Pen design: very similar.
Storage: refrigerated, then room temperature in use.
Side effect categories: nausea, constipation, reflux, fatigue.
Rare serious risks: pancreatitis, gallstones, severe gastroparesis on both.
Mechanism overlap: GLP-1 receptor activation in both. Tirzepatide adds GIP.

Which to choose for type 2 diabetes

Need maximum HbA1c reduction: lean Mounjaro on the SURPASS-2 evidence.
Have established cardiovascular disease: Ozempic still has the strongest CV outcomes data (SUSTAIN-6). Tirzepatide CV trials are maturing.
Already responding well to Ozempic: probably no reason to switch.
Insufficient response on Ozempic 1 mg: ask about escalating to 2 mg first; consider Mounjaro if 2 mg also insufficient.
Newly diagnosed, fast-track to control: Mounjaro at 5 mg often works as fast as Ozempic at 1 mg.

Which to choose for weight loss

In the UK, the licensed weight-loss versions are Mounjaro (under that brand for both diabetes and weight) or Wegovy (semaglutide branded for weight loss).
Ozempic is NOT licensed for weight loss in the UK. If your reason is weight only, you'd be looking at Mounjaro vs Wegovy, not vs Ozempic.
Mounjaro for weight loss in the UK: licensed by NICE TA1026 for adults with BMI ≥35 plus a weight-related condition.
On weight loss specifically: Mounjaro 15 mg → ~22% loss at 72 weeks (SURMOUNT-1); Wegovy 2.4 mg → ~15% (STEP 1).

Side effects compared

Nausea: similar on both at equivalent therapeutic doses (peaking at dose escalations, 30-50% across trials).
Constipation: Ozempic 1 mg ~6% (SUSTAIN/PIONEER); Mounjaro 5-15 mg ~6-9% (pooled SURPASS 1-5).
Diarrhoea: Mounjaro slightly higher across all doses.
Reflux: similar incidence on both.
Hypoglycaemia: low risk on either as monotherapy. Higher when combined with sulfonylureas or insulin.
Hair shedding: reported on both, more common at higher doses, usually reversible.

Cost and access

NHS for diabetes: both are routinely available; specific local pathways depend on the diabetes service.
NHS for weight loss: both restricted to specialist Tier 3 services. Capacity is limited.
Private prescription: both £150-300/month depending on dose. Mounjaro often slightly cheaper at lower-equivalent doses.
Supply: intermittent for both since 2023; Mounjaro has been more stable in late 2025.

Common questions

Is Mounjaro better than Ozempic for diabetes?: On HbA1c reduction and weight loss, yes, SURPASS-2 showed clear advantages. On established cardiovascular outcomes data, Ozempic still leads. For most people newly starting GLP-1 therapy without prior CV disease, Mounjaro is the more efficacious choice.
Should I switch from Ozempic to Mounjaro?: If your HbA1c and weight goals are met on Ozempic, no reason to switch. If you're at 1-2 mg Ozempic and not at target, switching to Mounjaro under prescriber supervision is reasonable. Don't self-switch; dose conversions aren't 1:1.
Can Ozempic be used off-label for weight loss?: Some private clinics do this in the UK. NHS doesn't. Off-label use raises ethical and supply concerns, using a diabetes drug for weight loss can contribute to shortages for diabetic patients. Wegovy or Mounjaro for licensed weight management is the cleaner route.
What about Mounjaro vs Wegovy for weight loss?: See our Mounjaro vs Wegovy comparison. Short version: SURMOUNT-5 head-to-head showed Mounjaro 20.2% vs Wegovy 13.7% weight loss at 72 weeks. Mounjaro wins on weight loss; Wegovy has more years of safety data.