What is tirzepatide?
Tirzepatide is the active ingredient in Mounjaro, a once-weekly injection. In the UK it is licensed for type 2 diabetes and, since November 2023, for weight management in adults.
In the SURMOUNT-1 trial, adults with obesity or overweight who took the highest dose (15mg) lost on average 20.9% of their body weight over 72 weeks, compared with 3.1% on placebo. Results vary between people, and Mounjaro is used alongside a reduced-calorie diet and more physical activity.
Compared with the semaglutide in Wegovy, tirzepatide acts on two hormone pathways instead of one. Read our comparison of Mounjaro vs Wegovy.
How does tirzepatide work?
Tirzepatide is a dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist. GIP and GLP-1 are hormones called incretins that your gut releases after you eat.
Both hormones increase the release of insulin. GLP-1 also slows the emptying of the stomach and acts on the brain to reduce appetite, which helps you eat less.
Mounjaro is injected once a week under the skin of the tummy, thigh or upper arm. Treatment starts at 2.5mg once a week for four weeks, then 5mg. Your prescriber can increase the dose in steps of 2.5mg, at least four weeks apart, up to a maximum of 15mg once a week.
Is tirzepatide available in the UK?
Yes. The MHRA authorised Mounjaro for weight management and weight loss in adults on 8 November 2023. The licence covers adults with a BMI of 30 or above, or a BMI of 27 or above with at least one weight-related health condition, such as high blood pressure or prediabetes.
On the NHS, access is being introduced in phases. Privately, a UK-registered clinician decides whether Mounjaro is suitable for you. The most common side effects are digestive, such as nausea, diarrhoea and constipation.
How can I get Mounjaro?
PrivateDoc can prescribe Mounjaro if a UK-registered clinician decides it is suitable for you. The consultation is free and you only pay if a prescription is approved. See Mounjaro treatment or all weight loss treatments.
