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Tirzepatide: Medical Uses and Prescription Guide

The active ingredient in Mounjaro – how it differs from semaglutide and how prescribing works.

Published 20 October 2026 · Last reviewed 20 October 2026 · Editorial content by the Peptide Atelier UK team, not clinically reviewed

Editorial standards and corrections

Educational information only. Tirzepatide is a prescription-only medicine. Peptide Atelier UK does not sell, supply or prescribe it. This page is not medical advice; speak to a GP, pharmacist or other qualified healthcare professional.

What is tirzepatide?

Tirzepatide acts on two hormone receptors: GIP (glucose-dependent insulinotropic polypeptide) and GLP-1. This dual action distinguishes it from semaglutide, which acts on GLP-1 receptors only.

Authorised uses

In the UK, tirzepatide is marketed as Mounjaro, a weekly injection authorised for adults with type 2 diabetes and for weight management in specific adults alongside diet and physical activity. Check the official product information for current indications.

Safety considerations

Gastrointestinal side effects are common, especially when starting or increasing the dose. The MHRA has issued guidance on using effective contraception and on the possible reduced effectiveness of oral contraceptives in some circumstances. Tirzepatide should not be used during pregnancy. Discuss all medicines and conditions with your prescriber.

The prescription pathway

A registered prescriber assesses suitability, starts treatment at a low dose and reviews progress. In England, NHS access for weight management follows NICE guidance. Private services must be provided by registered prescribers and dispensed by GPhC-registered pharmacies.