Mounjaro vs Wegovy: UK Clinical Comparison (Patient Information)

Important information for UK consumers

Mounjaro (tirzepatide) and Wegovy (semaglutide 2.4mg) are prescription-only medicines (POMs) in the UK. UK regulations restrict the advertising of prescription medicines to the public, so this article is a clinical comparison for patient information — it is not an advertisement, not an offer of sale, and not medical advice. TreatCompare does not display UK prices for Mounjaro or Wegovy.

A side-by-side clinical comparison of Mounjaro (tirzepatide) and Wegovy (semaglutide 2.4mg) covering mechanism, indication, dose schedule, safety and NHS access. Suitability is a clinical decision for a UK-registered prescriber.

Side-by-side clinical comparison

	Mounjaro	Wegovy
Active ingredient	Tirzepatide	Semaglutide
Mechanism	Dual GIP / GLP-1 receptor agonist	GLP-1 receptor agonist
Manufacturer	Eli Lilly	Novo Nordisk
UK indication (weight management)	NICE TA1026	NICE TA875
Starting dose	2.5mg weekly	0.25mg weekly
Maintenance dose	Up to 15mg weekly (clinical decision)	2.4mg weekly
Administration	Weekly subcutaneous injection (KwikPen)	Weekly subcutaneous injection (FlexTouch pen)
Pivotal trial	SURMOUNT-1	STEP-1
Mean trial body-weight reduction	~21% at 15mg over 72 weeks	~15% at 2.4mg over 68 weeks

Trial endpoints are population averages. Individual response varies by dose, adherence and other factors. The medicines have not been directly compared in a head-to-head trial. UK prices are not displayed on this site.

Key clinical differences

Mechanism of action

Mounjaro (tirzepatide) acts on both GIP and GLP-1 receptors — a dual incretin approach. Wegovy (semaglutide) acts only on the GLP-1 receptor. No head-to-head trial between the two medicines has been published.

Dose flexibility

Mounjaro offers maintenance dose options up to 15mg weekly, giving prescribers flexibility to adjust based on response and tolerability. Wegovy has a single target maintenance dose of 2.4mg, reached through a fixed escalation schedule.

NICE / NHS context

Both are recommended by NICE for weight management. Wegovy under TA875 (NHS access via specialist Tier 3 services). Mounjaro under TA1026 (phased NHS England cohort rollout decided by NHS England commissioning policy).

Safety profile

Both share a broadly similar safety profile dominated by gastrointestinal effects during dose escalation. See the side-effects comparison and the MHRA Drug Safety Update on GLP-1 receptor agonists.

NHS access

Both medicines are recommended by NICE for weight management. NHS eligibility is set by NICE technology appraisals and NHS England commissioning policy:

•BMI thresholds and required comorbidities depend on the specific appraisal and current commissioning rules.
•Tirzepatide is rolled out in phased cohorts; semaglutide 2.4mg is accessed via Tier 3 services after GP referral.
•Lower BMI thresholds may apply for certain ethnic groups under current NICE guidance.

Check NHS weight-management eligibility →

Frequently asked questions

What is the difference between Mounjaro and Wegovy?▾

Mounjaro (tirzepatide) is a dual GIP/GLP-1 receptor agonist manufactured by Eli Lilly. Wegovy (semaglutide 2.4mg) is a GLP-1 receptor agonist manufactured by Novo Nordisk. Both are once-weekly subcutaneous injections licensed in the UK for weight management in eligible adults. Suitability is a clinical decision for a UK-registered prescriber.

Why does this page not show Mounjaro or Wegovy prices?▾

Mounjaro and Wegovy are prescription-only medicines (POMs) in the UK. UK Human Medicines Regulations 2012 prohibit advertising POMs to the public, and a side-by-side price comparison is treated as stronger inducement than a single price. TreatCompare therefore does not display UK Mounjaro or Wegovy prices.

Can I get Mounjaro or Wegovy on the NHS?▾

Both are recommended by NICE for weight management in eligible adults — tirzepatide under TA1026 and semaglutide 2.4mg under TA875. NHS access is decided by NHS England commissioning policy. Tirzepatide is rolled out in phased cohorts; semaglutide 2.4mg is accessed via specialist Tier 3 weight-management services after a GP referral. Speak to your GP for local availability.

Which produces more weight loss in trials?▾

SURMOUNT-1 reported mean body-weight reduction of around 21% with tirzepatide 15mg over 72 weeks. STEP-1 reported mean body-weight reduction of around 15% with semaglutide 2.4mg over 68 weeks. Trial endpoints are population averages; individual response varies, and the medicines have not been directly compared in a head-to-head trial.

Are Mounjaro and Wegovy interchangeable?▾

No. They contain different active ingredients (tirzepatide vs semaglutide), have different mechanisms (dual GIP/GLP-1 vs GLP-1 only), different dose schedules and different manufacturers. Switching between them is a clinical decision for a UK-registered prescriber.

UK weight-management hub

Patient information & provider directory

Mounjaro information

Tirzepatide UK patient information

Wegovy information

Semaglutide 2.4mg UK patient information

MHRA Yellow Card data

GLP-1 side-effects reporting

Sources & further reading

MHRA: Advertising of medicines (Blue Guide) — UK regulator guidance on advertising prescription-only medicines to the public
NICE TA1026 — Tirzepatide for managing overweight and obesity — NICE technology appraisal for Mounjaro (tirzepatide)
NICE TA875 — Semaglutide for managing overweight and obesity — NICE technology appraisal for Wegovy (semaglutide 2.4mg)
MHRA Drug Safety Update: GLP-1 receptor agonists — UK pharmacovigilance and safety reporting for GLP-1 weight-management medicines

Important disclaimer

This page is general patient information, not medical advice. Whether Mounjaro, Wegovy or any other treatment is clinically appropriate is a decision for a UK-registered prescriber following an assessment. TreatCompare does not display UK prices for prescription-only medicines on consumer pages.