At what dose does Wegovy start to work — and what does 'working' actually mean?

You have just opened your first pen and it says 0.25mg, here is what is happening

The scenario is a common one: the pharmacist has sent a 0.25mg pen, you know the 'proper' dose is 2.4mg, and you are wondering whether anything useful is going on. Something is. Semaglutide (the active medicine in Wegovy) binds to GLP-1 receptors in the brain and gut from the very first injection, slowing how quickly the stomach empties and softening hunger signals. The early doses are calibrated low not because they are therapeutically empty but because the gastrointestinal system needs time to adjust. Starting at 0.25mg and stepping up roughly every four weeks keeps nausea and other digestive symptoms at a manageable level for most people.

That said, 0.25mg is not where significant weight change tends to appear on the scales. The evidence on what 0.25mg Wegovy does in practice suggests appetite suppression can begin early, but measurable weight reduction at this level is modest. Think of the first pen as your body's introduction to the medicine rather than the main event. The STEP 1 trial, published in the New England Journal of Medicine, ran participants to 68 weeks and reported its headline ~15% average weight reduction at the 2.4mg maintenance level, not at the starter dose.

One habit worth building in week one: note your starting weight and take it again at the same time of day, on the same scales, roughly every two to four weeks. That single check, once a month, gives you and your prescriber the evidence needed to assess progress rather than guessing.

The doses where most people notice a shift

The Wegovy schedule moves through 0.25mg, 0.5mg, 1mg, 1.7mg and finally 2.4mg, with each level held for roughly four weeks before increasing, and understanding at what dose Wegovy starts working can help set realistic expectations as you move through that schedule. The transition from 0.5mg to 1mg is where many people report the first clear change in eating behaviour, portions feel smaller without effort, the pull towards snacking between meals quietens. What happens at the 1mg dose matters more than most people realise, because it is where the prescriber can also assess whether the medicine suits you well enough to continue the schedule.

The fuller effect on body weight accumulates progressively. By the time someone reaches 2.4mg and has been on it for several months, the compound effect of sustained appetite reduction alongside the lifestyle changes their prescriber has encouraged tends to show up clearly. NHS guidance on semaglutide describes this as a medicine that works best alongside a reduced-calorie diet and increased physical activity, the dose creates the conditions, the lifestyle changes build on them.

For a fuller picture of how the whole schedule fits together, the Wegovy dosage guide covers the titration logic in detail. The short version: lower doses prime, higher doses sustain.

The 2.4mg maintenance dose, and what comes after it

Most people who complete the titration end up at 2.4mg weekly. This is the dose at which the STEP 1 trial recorded its headline result, and it is the level NICE considers the maintenance dose for its recommendation under TA875. NICE's guidance also sets a practical checkpoint: if less than 5% weight loss has occurred after six months at the highest tolerated dose, whether to continue should be reviewed. That is not a verdict on whether Wegovy works in general, it is a clinical signal that a different approach may be needed for that individual.

There is now a higher option. On 14 April 2026, the MHRA approved a dedicated single-dose 7.2mg pen. Trials at that level reported around 20.7% average weight loss over 72 weeks (narrowing the gap with tirzepatide 15mg) though this dose is approved only for adults with a BMI of 30 or above and the starting point remains 0.25mg, titrated upward by a prescriber. The full breakdown of Wegovy's available strengths explains which formats are licensed and what each is used for.

If you have been on 2.4mg for some time and progress has stalled, that is a recognised pattern. A prescriber can review whether the 7.2mg option is appropriate, or whether other factors (sleep, stress, adherence) are worth addressing first. The guide to plateaus on 2.4mg covers this in practical detail.

What this means if you are deciding whether to start

Wegovy works at the maintenance dose for most people who complete the titration and stay on treatment. The early doses are part of getting there safely. A prescriber does not skip the starter doses to get results faster, the schedule is there for good clinical reasons, and rushing it increases the chance of side effects that lead people to stop altogether.

Eligibility for private treatment requires a BMI of 30 or above, or 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. A prescriber assesses the whole picture (medical history, other medicines, lifestyle) before approving any prescription. If you would like to understand the broader range of licensed treatments available, the weight-loss treatment overview lays them out clearly.

At nume, every consultation is reviewed by a GPhC-registered Independent Prescriber on the day it is submitted. A real clinician reads your answers, not automated software. If Wegovy is clinically appropriate for you, treatment can be dispatched the same day and arrive the next working day by tracked delivery. Check your eligibility and start your free consultation.