Wegovy Measurements Explained: Reading the Numbers on Your Pen

What the STEP 1 trial tells us about the 2.4 mg measurement

The most cited evidence for Wegovy comes from the STEP 1 trial, a 68-week study in adults with obesity or overweight plus at least one weight-related condition, without type 2 diabetes. Participants who reached the 2.4 mg weekly dose lost an average of around 15% of their body weight, compared with roughly 2.4% in the placebo group. Those are the semaglutide measurements that informed the UK licence and that NICE cited in its appraisal of semaglutide for weight management (TA875). The 2.4 mg figure is not a magic number, it is the dose at which the medicine's appetite-reducing effect reaches its licensed maximum. Whether a patient stays at 1.7 mg or pushes to 2.4 mg depends on tolerability and clinical judgement, not the number alone. The STEP 1 paper in the New England Journal of Medicine remains the primary evidence base for this dose-response relationship.

It is worth keeping these figures in proportion. A 15% average reduction means some participants lost considerably more and some considerably less. Averages describe populations; your prescriber tracks what the measurements mean for you specifically.

How the 0.25 mg starting measurement fits into the picture

The 0.25 mg pen is not a therapeutic measurement in the sense of producing meaningful weight loss on its own. Its job is adjustment. Semaglutide slows gastric emptying and acts on GI receptors, which means beginning at the full maintenance dose would almost certainly cause significant nausea for most people. Starting lower and titrating in roughly four-week steps lets the body acclimatise before the dose climbs. The NHS medicines page for semaglutide describes this graduated approach, and it is the reason the schedule exists in the order it does. You can read more about how each Wegovy increment is structured and what to expect at every stage if you want a fuller breakdown of each rung. The measurement on the pen is a clinical tool, not a score of how well treatment is going.

Many people find the transition from 1.0 mg to 1.7 mg the most noticeable step in terms of appetite change. Others feel the difference most at 2.4 mg. There is no universal experience, which is exactly why clinical review before each increase matters.

The 7.2 mg measurement: what the MHRA approval means

The measurement landscape for Wegovy changed in early 2026. In January, the MHRA approved 7.2 mg as a new maximum dose, initially supplied as three 2.4 mg pens used together. On 14 April 2026 the MHRA approved a dedicated single-dose 7.2 mg pen, one pre-set weekly injection with a built-in covered needle that locks after use. Trial data for the 7.2 mg measurement reported approximately 20.7% average weight loss over 72 weeks, narrowing the gap with tirzepatide's top-dose results. You can find details of the approval on the GOV.UK announcement from April 2026. The 7.2 mg pen is licensed for adults with a BMI of 30 or above; it is not licensed at lower BMI thresholds or for cardiovascular risk reduction. Specific dose availability is always confirmed at the point of clinical assessment, not beforehand. If you are exploring whether any Wegovy measurement is appropriate for you, our Wegovy overview covers the licensed eligibility criteria in full.

Measurements on paper versus what the prescriber decides

Reading about semaglutide measurements online is useful background, but the number your prescriber chooses for you depends on factors a webpage cannot assess: how you tolerated the previous dose, whether any side effects need managing, your current weight and health picture, and (where relevant) what other medicines or supplements you take alongside treatment. Our prescribers at nume review every repeat order individually before any dose change is authorised; there is no automated step-up. If you are thinking about where nutrition fits into treatment alongside these measurements, our guidance on which supplements to take with Wegovy and why each one matters covers the key considerations, including our more detailed look at how Wegovy and iron supplements interact, which is a practical question many people on longer-term treatment raise. And if you are weighing up whether private treatment is the right route, the free consultation is the practical next step, a real prescriber reads your answers the same day, not a queuing system. Many people find it takes about as long as making a cup of tea.