Do Some People Respond Better to Semaglutide Than Tirzepatide?

What the head-to-head trial tells us, and what it doesn't

SURMOUNT-5 is the most useful data we have. In that 72-week open-label trial of 751 adults with obesity and no diabetes, tirzepatide produced a greater average weight reduction than semaglutide 2.4mg. NICE's appraisal of tirzepatide (TA1026) noted indirect comparisons also favour tirzepatide, and that shaped its recommendation. So the population-level verdict is clear enough.

But a trial average is a summary of a distribution. Inside that distribution are people for whom semaglutide produced more weight loss than tirzepatide did, for reasons the trial wasn't designed to unpick. Some had better tolerability on the GLP-1-only pathway. Some had prior GIP-pathway variation. Some simply stayed on semaglutide at full dose for longer because they found it easier to manage.

The gap also narrows at the newer semaglutide dose. The MHRA approved a 7.2mg semaglutide maintenance dose (now available as a dedicated single-dose Wegovy pen) and trials at that level reported around 20.7% average weight loss over 72 weeks, approaching tirzepatide 15mg results. That changes the calculus for people who tolerate semaglutide well but struggle with tirzepatide's dual-agonist effects, and if you're wondering whether Mounjaro and Wegovy are actually the same medication, our dedicated page explains the key differences. If you want to understand whether Mounjaro or semaglutide is the better choice, our dedicated page works through the evidence in detail. You can read a fuller breakdown of the two medicines in our Wegovy versus Mounjaro comparison.

Biology and tolerability: where individual response diverges

Tirzepatide activates both GIP and GLP-1 receptors. That dual action is likely why its average results are stronger. But GIP receptor expression varies between people, and some individuals' GI systems react more strongly to that second pathway, producing nausea, vomiting or reflux that limits dose escalation. If a person can only reach 7.5mg comfortably while someone else reaches 15mg, the comparison to semaglutide 2.4mg looks very different in each case.

Semaglutide works through the GLP-1 pathway alone. That single-mechanism profile suits some people better, the dose escalation feels more predictable, side effects are familiar to the prescribing team, and the evidence base (including the STEP 1 trial in the New England Journal of Medicine) is large and long-standing. For people who've previously used a GLP-1 agent and tolerated it well, re-engaging with the same pathway may be the smoother path.

The NHS patient information for tirzepatide notes the common GI side-effect profile plainly (nausea, vomiting, diarrhoea, constipation) and the same categories appear for semaglutide, though the severity distribution differs person to person. Tolerability is a clinical judgement, not a coin flip, and it's one our prescribers work through with you.

Practical factors that shift the decision

Results in a trial setting and results in real life aren't always the same thing. A medicine works best when the person takes it consistently, at the dose they can sustain. Several practical factors can tip the balance toward semaglutide for a given individual.

The oral Wegovy tablet (approved by the MHRA in June 2026 as the first oral GLP-1 medicine licensed in the UK for weight management) removes the injection entirely. For someone with needle anxiety or a lifestyle that makes weekly injections difficult, the pill format alone can be decisive. There's no equivalent oral option for tirzepatide in the UK. If you're weighing up whether the injection or the tablet suits you better, and want to understand whether semaglutide or tirzepatide is the better fit for your circumstances, that page covers the options side by side.

Contraception is another practical consideration worth flagging early. NHS guidance advises women using oral contraceptives to add a non-oral method for the first four weeks on tirzepatide and for four weeks after each dose increase, because absorption of the pill may be reduced. No equivalent advisory exists for semaglutide under current UK guidance. For some women that's a minor inconvenience; for others it's a material factor. Similarly, those on oral HRT may be advised to consider a transdermal form while on tirzepatide. Details like these belong in a clinical conversation, not a checklist, our FAQs cover some of the common practical questions.

How the decision gets made at a clinical consultation

No comparison article, however thorough, can answer this question for a specific person. The decision rests on your BMI, your comorbidities, your medication list, your history with GI symptoms, your preferences about injections versus tablets, and your capacity to manage whichever titration schedule you're given.

At nume, a GPhC-registered Independent Prescriber reviews your full picture, not a standardised algorithm. That means the medicine recommended is the one that fits your clinical profile, not the one that tops a population average. If you're already on one and wondering whether you'd do better on the other, that's equally a clinical conversation: our page on which is better, semaglutide or tirzepatide, is a useful starting point before switching, though any change requires review of your current weight loss, your tolerability record and whether a change is appropriate at this point. Our clinical team handles exactly this kind of nuanced review.

The weight-loss treatment overview sets out both options clearly. When you're ready to let a prescriber look at your actual situation rather than a statistical average, many people also find it helpful to read what's better, semaglutide or tirzepatide, before starting a free consultation as the practical next step. Which medicine suits you is a clinical decision our prescribers make with you.