This article is for information only. Mounjaro is a prescription medicine requiring a doctor's assessment. Nothing here is medical advice.
What makes Mounjaro different
Mounjaro is tirzepatide, injected once a week. What sets it apart from the other two is that it acts on two hormones rather than one.
Wegovy and Saxenda target GLP-1 alone. Mounjaro targets GLP-1 and GIP together. GIP appears to improve insulin sensitivity and reinforce the appetite-suppressing signal, and this dual action is the leading explanation for the difference in results.
How much weight comes off
In SURMOUNT-1, the highest-dose group lost about 20.9% of body weight over 72 weeks — the largest reduction reported so far for a drug in this class.
- •About 21 kg for someone at 100 kg
- •Clearly ahead of Wegovy's roughly 14.9%
- •Results on preserving muscle relative to fat loss have also been comparatively favourable
Side effects
The profile is much the same as the rest of the class: nausea, vomiting, diarrhoea and constipation lead.
Preclinical comparisons have reported fewer gastrointestinal effects from tirzepatide than from equally effective doses of semaglutide. How fully that carries over to people is still being established.
- •Pancreatitis and gallbladder problems — rare but present
- •Gastroparesis and bowel obstruction warnings apply across the class
- •Contraindicated with a history of medullary thyroid carcinoma or MEN2
- •Low blood sugar risk when combined with diabetes medication
Approved indications, reimbursement and pricing change over time and differ by country. Treat anything you read — including this — as a starting point, and confirm the current position with a clinic.