Mounjaro

Key facts

• FDA approved Mounjaro for type 2 diabetes on 13 May 2022 and Zepbound (the US weight-management brand of tirzepatide) on 8 November 2023. Zepbound was also approved for obstructive sleep apnoea in adults with obesity on 20 December 2024.
• Authorised in the EU on 15 September 2022; weight management was added to the EU licence in December 2023 and to the UK licence on 8 November 2023.
• Dosing: start at 2.5 mg once weekly; if more effect is needed, increase in 2.5 mg steps after at least 4 weeks on each dose. The adult maximum is 15 mg weekly. In the US, Mounjaro is also approved for type 2 diabetes in children aged 10 and over (maximum 10 mg).
• SURPASS-2 (40 weeks, type 2 diabetes): HbA1c fell 2.01, 2.24 and 2.30 points with 5, 10 and 15 mg vs 1.86 points with semaglutide 1 mg injection.
• SURMOUNT-1 (72 weeks, obesity without diabetes): mean weight change -20.9% with 15 mg vs -3.1% with placebo.
• SURMOUNT-5 (72 weeks, head to head): -20.2% with tirzepatide vs -13.7% with Wegovy (semaglutide 2.4 mg).
• SURPASS-CVOT: major cardiovascular events 12.2% with tirzepatide vs 13.1% with dulaglutide (hazard ratio 0.92), meeting non-inferiority but not superiority. The FDA added a cardiovascular risk reduction indication to Mounjaro on 27 August 2026.
• Compared with Rybelsus: a weekly injection rather than a daily tablet, with no fasting rules, and larger average HbA1c and weight reductions in trials; but it is a different molecule and is not a semaglutide product.
• The MHRA advises people using oral contraceptives with tirzepatide to add a barrier method for 4 weeks after starting and after each dose increase, and to stop tirzepatide at least 1 month before trying for a baby.
• US labelling carries a boxed warning about thyroid C-cell tumours seen in rodents.

Where Mounjaro is available