Is Tirzepatide the Same as Wegovy? What the Difference Actually Means for You

The biggest misconception: same purpose, same drug

People searching "is tirzepatide the same as Wegovy" usually come from one of two places: they've been quoted both by a clinic and want to know if they're interchangeable, or they've seen the headlines about Mounjaro's results and want to know how close Wegovy gets. The answer to both is: they're not the same, and the gap between them is clinically meaningful.

Tirzepatide (Mounjaro) activates two gut-hormone receptors simultaneously — GIP and GLP-1. Wegovy (semaglutide) targets GLP-1 only. That dual action is why tirzepatide is often described as a dual agonist, and it's the likely reason for the difference in average weight loss seen in clinical trials. The head-to-head comparison of Wegovy and Mounjaro is worth reading if you want the full trial breakdown, but the short version is this: they are different molecules, different mechanisms, different prescribing decisions.

A third name that often creates confusion is Ozempic. Ozempic is also semaglutide (the same molecule as Wegovy) but licensed for type 2 diabetes management, not weight loss. It's not interchangeable with Wegovy for weight purposes, and it isn't something a prescriber should offer for weight management. Our page on tirzepatide and Ozempic covers that distinction in more detail.

What the trial numbers actually show

Both medicines have substantial evidence behind them, so neither is a marginal treatment. The question is the size and consistency of the effect.

In the SURMOUNT-1 trial (2,539 adults with obesity, no diabetes, 72 weeks), tirzepatide at the 15mg dose produced an average body-weight reduction of around 20–21%, with some analyses reaching approximately 22.5%, published in the New England Journal of Medicine. In the STEP 1 trial, semaglutide 2.4mg (Wegovy's standard maintenance dose) produced around 15% average reduction over 68 weeks. The MHRA subsequently approved a higher 7.2mg Wegovy dose (a dedicated single-dose pen received approval on 14 April 2026) with trials reporting around 20.7% average loss at that dose, which narrows the gap considerably. SURMOUNT-5, a direct head-to-head trial published in 2025, found tirzepatide produced greater average weight loss than semaglutide 2.4mg in adults with obesity over 72 weeks. NICE cited indirect comparisons favouring tirzepatide in its appraisal (TA1026).

What these numbers don't tell you is which medicine will suit your biology, your other health conditions, your current medicines, or your preference for injection versus tablet. That's what a prescriber works out with you. Those who want to dig into cost alongside efficacy will find the price comparison between Mounjaro and Wegovy useful context before a consultation.

Eligibility: where the licences converge and diverge

The licensed eligibility thresholds are similar at the headline level: adults with a BMI of 30 or above, or a BMI of 27 or above with at least one weight-related condition such as high blood pressure, type 2 diabetes, or obstructive sleep apnoea. Lower BMI thresholds apply for some ethnic backgrounds under UK guidance. Beyond that, NICE's NHS recommendations differ meaningfully. Tirzepatide under TA1026 is recommended for adults with BMI ≥35 and at least one weight-related comorbidity; semaglutide under TA875 is recommended only within a specialist weight management service for a maximum of two years. The private licensed thresholds are broader for both, and either way the prescriber assesses the full picture, BMI alone doesn't determine the outcome.

For a detailed look at how the two medicines sit within NHS access criteria, the Wegovy vs Mounjaro page sets this out clearly. If you're specifically trying to understand the semaglutide side of the comparison, this page on tirzepatide and semaglutide covers the molecular relationship in more depth.

Side effects, practical use, and what choosing between them involves

Both medicines share a broadly similar side-effect profile: nausea, loose stools, constipation, indigestion, burping, and fatigue are the most frequently reported, particularly in the early weeks after starting or after a dose increase. These tend to ease as the body adjusts. Severe or persistent stomach pain that radiates to the back is a reason to seek medical attention promptly, the MHRA flagged acute pancreatitis as a known but infrequent risk across GLP-1 medicines in January 2026. The NHS medicines pages for tirzepatide and semaglutide set out both safety profiles in plain language.

Practical differences do exist. Wegovy now comes in an oral tablet form (25mg maintenance, licensed by the MHRA on 11 June 2026) as well as the injection pen, which changes the conversation for anyone who prefers not to inject. Tirzepatide remains injection-only as a licensed weight-loss option. Wegovy tablets require a strict morning routine: first thing on an empty stomach, with a small amount of plain water, at least 30 minutes before food or other medicines. The injections for both can be done at home and rotated between the abdomen, thigh, or upper arm.

Which suits you is a clinical decision our prescribers make with you. If you're ready to start that conversation, our free consultation takes the process from there.