Mounjaro vs Wegovy

Two different active substances

Mounjaro's active substance is tirzepatide, made by Eli Lilly. Its SmPC says: "Tirzepatide is a long acting GIP and GLP-1 receptor agonist." The NHS medicines guide calls it "a dual agonist that activates the gut hormone receptors GLP-1 and GIP".

Wegovy's active substance is semaglutide, made by Novo Nordisk. The Wegovy SmPC describes semaglutide as a GLP-1 analogue that "acts as a GLP-1 receptor agonist". Semaglutide is also the active substance in Ozempic and in Wegovy tablets, each with its own licence.

The two SmPCs are separate documents and neither compares one medicine with the other. This page sets out where the product information and the NICE guidance differ. Which medicine is suitable for a person is a decision for their prescriber.

What each UK licence covers

The two licences share one indication: weight management, including weight loss and weight maintenance, alongside a reduced-calorie diet and increased physical activity, in adults with an initial BMI of 30 kg/m² or more, or of 27 to under 30 kg/m² with at least one weight-related comorbidity.

Mounjaro is also licensed for insufficiently controlled type 2 diabetes, as an adjunct to diet and exercise, in adults and in children and adolescents aged 10 and over. Wegovy holds no diabetes licence. The MHRA guide to GLP-1 medicines lists semaglutide for diabetes under the brand names Ozempic and Rybelsus.

Wegovy's licence covers some uses that Mounjaro's does not. It includes weight management in adolescents aged 12 and over with obesity and a body weight above 60 kg. It also covers reducing the risk of major adverse cardiovascular events in adults with established cardiovascular disease and a BMI of 27 kg/m² or more, and treating non-cirrhotic metabolic dysfunction-associated steatohepatitis (MASH) with moderate to advanced liver fibrosis.

Pens and strengths

Wegovy comes in the FlexTouch pen and Mounjaro in the KwikPen. Both are pre-filled multidose pens that hold four weekly doses. The Wegovy SmPC says: "This pen is for multi-use. It contains 4 doses." The Mounjaro SmPC says: "Each KwikPen contains 4 doses of 0.6 ml which can be administered."

Each pen is made in one strength. The emc lists Wegovy FlexTouch pens at 0.25 mg, 0.5 mg, 1 mg, 1.7 mg and 2.4 mg, and Mounjaro KwikPens at 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg and 15 mg. The milligram figures belong to two different substances, so a figure on one box cannot be compared with a figure on the other.

Wegovy also has a 7.2 mg dose, which its SmPC limits to weight management in adults with obesity. The MHRA approved a single-dose 7.2 mg pen in April 2026, and it comes in a pack of 4 pens. The SmPC says the 7.2 mg dose is given either as one 7.2 mg injection or as three 2.4 mg injections one after the other, depending on the device. Both SmPCs describe a starting dose that is increased in steps, and the prescriber decides the strength and when it changes.

Needles and what is in the box

The Wegovy SmPC lists each FlexTouch pack as "1 multiple dose pre-filled pen and 4 disposable NovoFine Plus needles". The Mounjaro SmPC lists packs of 1 and 3 KwikPens and states: "Needles are not included in the pack." Needles for a KwikPen therefore come separately, and the dispensing pharmacy can confirm what an order includes.

The Wegovy 7.2 mg pen is a single-dose pen with its needle attached, supplied in a pack of 4 pens.

Storage before and after first use

Both pens are kept in a fridge at 2°C to 8°C before first use, and neither may be frozen. Once a Wegovy FlexTouch pen is in use, its SmPC gives an in-use shelf life of 6 weeks, stored below 30°C or, preferably, in a fridge. After first use, the Mounjaro SmPC says a KwikPen "may be stored unrefrigerated for up to 30 days at a temperature not above 30 °C" and must then be discarded.

NHS access: TA875 and TA1026

NICE technology appraisal TA875 recommends semaglutide (Wegovy) for weight management within a specialist weight management service and for a maximum of 2 years. It applies to adults with at least one weight-related comorbidity and a BMI of at least 35.0 kg/m², or of 30.0 to 34.9 kg/m² when they meet the criteria for referral to a specialist service.

TA1026 recommends tirzepatide (Mounjaro) for adults with an initial BMI of at least 35 kg/m² and at least one weight-related comorbidity. NICE says it "can be used in primary care or specialist weight management services", and a funding variation means it is being introduced in phases under NHS England's interim commissioning guidance.

Both appraisals use lower BMI thresholds, usually 2.5 kg/m² lower, for people from South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean family backgrounds. NICE has also published TA1152 on semaglutide for reducing cardiovascular risk and TA924 on tirzepatide for type 2 diabetes. Its appraisal of the Wegovy 7.2 mg dose (ID6699) is in development.

NICE guidance decides NHS funding in England. It does not set the conditions for a private prescription, and whether someone qualifies on the NHS is for the clinicians who assess them.