Mounjaro or Wegovy – what is the difference?

Wegovy contains semaglutide. According to the prescribing information (SmPC), it is a GLP-1 analogue that is 94 percent identical to the body's own gut hormone GLP-1 and selectively activates the GLP-1 receptor. The result: less hunger, feeling full sooner, slower gastric emptying.

Mounjaro contains tirzepatide. The prescribing information describes it as a long-acting GIP and GLP-1 receptor agonist. So it additionally targets the receptor for GIP, a second gut hormone. Exactly why this combination works more strongly is not yet fully understood.

You'll find more about the active substances in the peptide index: Tirzepatide and Semaglutide.

For a long time there were only separate trials. SURMOUNT-5 was the first to compare the two medications directly (Aronne et al., New England Journal of Medicine 2025; 393:26–36). 751 adults with obesity but without type 2 diabetes received the highest tolerated dose for 72 weeks: tirzepatide 10 or 15 mg or semaglutide 1.7 or 2.4 mg. The trial was funded by Lilly, the manufacturer of Mounjaro.

What the trial does not show: it did not include people with type 2 diabetes and ran only at trial sites in the USA and Puerto Rico. The newer Wegovy 7.2 mg dose was not tested. And it says nothing about hard endpoints such as heart attacks or strokes. Nor does it provide long-term data beyond 72 weeks.

These are averages. Many people also lose a lot of weight on semaglutide, and not everyone responds more strongly to tirzepatide. How fast it typically goes is covered in Losing weight on Mounjaro: how fast?

Both medications have a similar profile. The most common are nausea, diarrhoea, vomiting and constipation – especially while the dose is being increased. In SURMOUNT-5, gastrointestinal complaints in both groups mostly occurred during this phase and were usually mild to moderate.

One difference: injection site reactions were reported more often with tirzepatide (8.6 % vs. 0.3 %). Rare but serious side effects such as inflammation of the pancreas or gallbladder problems are listed in the prescribing information for both substances.

Details: Mounjaro side effects, Nausea and Gallbladder and pancreas.

All information according to the current EMA prescribing information. How far and how fast the dose is increased is decided by your doctor. On handling: KwikPen instructions.

In Germany, weight-loss medications are excluded from statutory health insurance benefits under § 34 SGB V. The G-BA (Federal Joint Committee) therefore classified Wegovy as a lifestyle medication in 2024. For weight loss you usually pay yourself, with a private prescription. Politicians are discussing changes; if in doubt, ask your health insurance.

One pen lasts 4 weeks. According to a price comparison, German pharmacy prices in September 2026 were roughly as follows:

• Mounjaro: from approx. €207 (2.5 mg) through approx. €278 (5 mg) and approx. €384 (7.5/10 mg) up to approx. €490 (12.5/15 mg) per pen
• Wegovy: depending on strength and supplier approx. €170 to €375 per pen, the 2.4 mg maintenance dose from approx. €278

Prices change often, so check them before buying. More under Mounjaro cost and prescription.

There is no general recommendation. Points that can play a role in the conversation with your doctor:

• How much weight loss makes medical sense
• Pre-existing conditions, other medications and previous tolerability
• Cost at the respective maintenance dose
• Whether a medication already works well and is well tolerated – then switching is not a must

Switching between the two should only be done under medical supervision, not simply with a “converted” dose. This text is general information and not medical advice.