Dual GIP / GLP-1 receptor agonist · Evidence-led, sources cited
Mounjaro (Tirzepatide)
Licensed in the UK for weight management and type 2 diabetes.
How it works
Tirzepatide acts on two gut-hormone receptors (GIP and GLP-1), reducing appetite and slowing gastric emptying, which lowers how much you eat.
Published dosing
Per the Mounjaro SmPC, treatment starts at 2.5mg once weekly for four weeks, then increases to 5mg, with further increases only as a prescriber decides and you tolerate them.
Common side effects
The most commonly reported effects in the SmPC are gastrointestinal: nausea, diarrhoea, constipation, and reduced appetite — usually most noticeable after a dose increase.
What the evidence shows
In SURMOUNT-1 (NEJM, 2022), mean weight loss reached about 20.9% at 72 weeks on the highest dose. Individual results vary.