What dose should you start semaglutide on — and why that number matters

What the STEP 1 trial tells us about starting low

The STEP 1 trial, published in the New England Journal of Medicine, enrolled 1,961 adults with obesity or overweight and at least one weight-related condition. Every participant began on 0.25 mg weekly and moved through the same staged escalation before reaching the 2.4 mg maintenance dose. By 68 weeks the group on semaglutide had lost an average of roughly 15% of body weight. That result came from the maintenance dose, not from the starting one, but reaching the maintenance dose safely depended on the gradual build-up that preceded it.

The 0.25 mg starting dose produces little appetite suppression on its own. What it does is reduce the likelihood of nausea, vomiting and other gastrointestinal symptoms that can otherwise make the early weeks very uncomfortable. Clinical trials consistently showed that people who rushed through the early doses or skipped steps reported higher rates of side effects. The escalation schedule is, in that sense, a safety and tolerability structure as much as it is a dosing ladder.

The NHS semaglutide medicines page summarises the standard schedule and confirms that doses are usually increased every four weeks, though a prescriber may slow that pace if someone is finding a dose difficult to tolerate. That flexibility is written into the guidance. Moving faster than four weeks between steps is not supported by the evidence and is not something a responsible prescriber would suggest without exceptional clinical reason.

Why 0.25 mg is called a tolerability dose, not a treatment dose

Patients sometimes arrive at a consultation having read that semaglutide produces significant weight loss, and feel puzzled when they learn they will spend their first month on a dose that does very little in that direction. The reason is straightforward: GLP-1 receptor agonists like semaglutide slow gastric emptying and reduce appetite through a gut-hormone pathway that the body needs time to adjust to. Starting at a higher dose forces that adjustment too quickly, and the result is often nausea severe enough to make people stop treatment altogether.

The NHS England weight-management injections guidance notes that gastrointestinal effects are most common after starting or increasing a dose and generally settle within a few days to two weeks. Knowing that the discomfort is temporary (and tied to the dose adjustment rather than the medicine itself) helps people stay the course through the early steps.

One practical check worth doing each week: before you inject, confirm on the pen label that the dose matches what your prescriber has set for that stage of your schedule. It takes under a minute and catches any mix-up before it matters. Details about the full Wegovy dose range, including the higher strengths, are worth reading once you are established on treatment.

When and how doses increase (and what happens at the top

After the first four weeks on 0.25 mg, the standard schedule moves to 0.5 mg, then 1.0 mg, then 1.7 mg, and finally 2.4 mg) each step roughly four weeks apart, giving a total of about 16 to 20 weeks to reach the standard maintenance dose. Since January 2026 the MHRA has also approved a 7.2 mg maintenance dose for adults with a BMI of 30 or above; a dedicated single-dose 7.2 mg pen was approved in April 2026. Trials reported an average weight loss of around 20.7% over 72 weeks at 7.2 mg, bringing results closer to those seen with tirzepatide at its highest dose.

Not everyone will reach 2.4 mg or 7.2 mg. If a dose step proves difficult to tolerate, a prescriber can extend the time spent there before moving up, or in some cases hold at a lower maintenance dose if that is clinically appropriate. There is no rule that says you must reach the highest available dose, the goal is the dose that is both tolerated and effective for you. If you are thinking about whether starting at a higher dose is possible, the short answer from the licensed guidance is no: the 0.25 mg starting point applies to all new patients.

For anyone considering Wegovy for the first time, the overview on what Wegovy is and how it works covers the medicine's mechanism, licensed uses and eligibility criteria in full. Understanding the full picture before starting makes the early weeks feel less uncertain.

Semaglutide doses and who they are licensed for in the UK

Wegovy is licensed in the UK for adults with a BMI of 30 or above, or 27 to 29.9 with at least one weight-related condition such as high blood pressure, type 2 diabetes, dyslipidaemia or obstructive sleep apnoea. Lower BMI thresholds apply for some ethnic backgrounds under UK clinical guidance. The medicine is not licensed for use in pregnancy, breastfeeding, or in people trying to conceive, and it is not approved for under-18s. Anyone with a history of medullary thyroid carcinoma or MEN2 syndrome would not be suitable.

It is worth knowing that Ozempic is also semaglutide but is licensed specifically for type 2 diabetes management, not weight loss. Rybelsus is oral semaglutide licensed for diabetes at lower doses (3 mg, 7 mg and 14 mg). The oral weight-loss formulation is Wegovy tablets, approved by the MHRA in June 2026 at a separate dose schedule (1.5 mg to 25 mg). These are distinct medicines with distinct licences, and none of them should be confused with the Wegovy injection schedule described here.

If you are weighing up how the range of weight-loss treatments compare before deciding, that is a sensible place to start. Patients who want to understand what dose of Wegovy they should start with will find a detailed breakdown of the prescribing rationale helpful before their first consultation, and our guide to what dosage of Wegovy you should take across the full escalation schedule is also worth reading alongside it, as is our dedicated page covering what dose to start semaglutide on if you want a clear explanation of why the escalation begins where it does. When you are ready to find out whether Wegovy is clinically suitable for you, check your eligibility with our prescribers, the consultation is free, and a GPhC-registered prescriber reads every submission the same day.