Mounjaro®
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Start journey Learn moreWhat the evidence says about 2.5mg versus 5mg, and when the move up makes sense
What the SURMOUNT-1 data actually shows about dose and weight loss
The SURMOUNT-1 trial, published in the New England Journal of Medicine, followed 2,539 adults with obesity over 72 weeks across three maintenance doses: 5mg, 10mg and 15mg. Average weight reduction at 5mg sat around 15% of starting body weight. Participants on 15mg averaged roughly 20–21%. The trial did not include a 2.5mg maintenance arm, because 2.5mg was never designed to be held at, it's the entry rung that Eli Lilly built into every strength's schedule purely to reduce early nausea and GI discomfort.
What that tells you is that the jump from 2.5mg to 5mg is not a small incremental nudge. It's the transition from a physiological warm-up to a therapeutic dose. The NICE technology appraisal for tirzepatide (TA1026) draws on this data when it sets the expectation that meaningful weight reduction should be demonstrable; nobody is expected to achieve much at 2.5mg, because that isn't what it's for.
A practical check worth doing: if you're currently on 2.5mg and approaching the end of your first four weeks, note your weight now. That figure becomes the baseline your prescriber will use when deciding whether progress at 5mg is on track, and having it to hand takes less than a minute.
Comparing 2.5mg and 5mg directly: what changes and what stays the same
| Factor | 2.5mg (starter dose) | 5mg (first therapeutic dose) |
|---|---|---|
| Primary purpose | Tolerability and adjustment | Weight management |
| Average weight loss | Minimal (not a trial endpoint | Around 15% over 72 weeks at maintenance (SURMOUNT-1) |
| GI side effects | Common as the body adapts; typically ease within 1–2 weeks | May resurface briefly after the increase, then generally settle |
| Duration | Four weeks before prescriber reviews increase | Four weeks, then reviewed again; some stay here, some move further |
| Prescription requirement | Yes) clinical assessment required | Yes (prescriber-led titration decision |
Side effects across both doses follow a similar GI-led pattern) nausea, loose stools, reduced appetite, occasional fatigue, and the NHS tirzepatide page has a clear breakdown of what to expect and when to seek help. If you are weighing up whether you lose more weight on 5mg Mounjaro than on 2.5mg, the short answer is yes for most people, and the important thing to know is that a brief return of nausea after moving to 5mg is normal and does not mean the dose is wrong for you; it usually settles within a week or two.
Who stays at 5mg versus who moves higher, how that decision gets made
Not everyone progresses to 10mg or 15mg. Some people reach a comfortable, effective level at 5mg and stay there; whether a higher dose genuinely works better depends on your response, your tolerability and what your prescriber sees in your clinical picture. The titration schedule described in the Mounjaro SmPC (reviewed on the Electronic Medicines Compendium) is a framework, not a conveyor belt. Dose increases require evidence that the lower dose isn't producing adequate response and that you're tolerating it well enough to go further.
If you want a fuller picture of whether 5mg Mounjaro works better than 2.5mg, the answer for most people is yes, though by how much, and whether that difference justifies moving to a higher dose, is a clinical call. That's the honest shape of it.
At nume (at nume) our prescribers review every repeat order individually. They look at your progress, check whether a dose increase is appropriate, and make that call based on evidence you provide, not on a fixed schedule. If you're thinking about moving from 2.5mg to 5mg, or want to understand what Mounjaro 5mg involves and what to expect at that dose, the right place to resolve that is in a clinical conversation, not a comparison chart. Speak to our prescribers and get a proper answer for your situation.
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