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Weight loss injections · tirzepatide

Mounjaro (tirzepatide): UK guide

A once-weekly injection that acts on both GIP and GLP-1 receptors. Licensed in the UK for weight management alongside diet and physical activity.

Mounjaro at a glance

Licensed in the UK for weight managementPrescription-only medicine
Active ingredient
tirzepatide
Drug class
GIP/GLP-1 receptor agonist
Manufacturer
Eli Lilly
How it is taken
Injection, once a week
Device
KwikPen (multi-dose pre-filled pen)
Dose range
2.5mg to 15mg
MHRA authorisation
MHRA authorised for weight management, November 2023
NICE guidance
NICE TA1026 (December 2024)

Licensed in the UK for weight management. MHRA authorised for weight management, November 2023.

The main clinical evidence for Mounjaro in weight management comes from the SURMOUNT trial programme. Read what the trials show for context on realistic expectations.

Mounjaro doses

Treatment starts low and steps up gradually to help your body adjust.
Doses listed in the UK product information for Mounjaro. Your prescriber decides your dose; not everyone increases to the highest dose.
DoseRoleEarliest start (if increased at every step)
Mounjaro 2.5mgStarting doseWeek 1
Mounjaro 5mgStep-up doseWeek 5
Mounjaro 7.5mgStep-up doseWeek 9
Mounjaro 10mgMaintenance doseWeek 13
Mounjaro 12.5mgMaintenance doseWeek 17
Mounjaro 15mgMaximum doseWeek 21
  1. Step 12.5mgfrom week 1
  2. Step 25mgfrom week 5
  3. Step 37.5mgfrom week 9
  4. Step 410mgfrom week 13
  5. Step 512.5mgfrom week 17
  6. Step 615mgfrom week 21

The UK product information says to stay on each dose for at least 4 weeks before increasing. Weeks shown are the earliest possible; many people stay on a dose for longer, and some stay on a lower dose.

Mounjaro side effects

Select a side effect for self-care tips and guidance on when to seek help.

When to get urgent help

Stop taking the medicine and get urgent medical help (NHS 111, A&E or 999) if you have severe, persistent stomach pain that may spread to your back, signs of a serious allergic reaction, or yellowing of your skin or eyes. Report suspected side effects to the MHRA Yellow Card scheme.

Everything about Mounjaro

How Mounjaro compares

UK providers listing Mounjaro

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Mounjaro: frequently asked questions