Semaglutide Syringe Dosage: What the Clinical Evidence Tells Us

What the STEP 1 trial established about dose and weight loss

The dose schedule used in licensed Wegovy pens was not arrived at arbitrarily. The STEP 1 trial, published in the New England Journal of Medicine, studied 2.4 mg once-weekly semaglutide over 68 weeks in adults with obesity who did not have type 2 diabetes. Participants lost an average of around 15% of their body weight. That figure represents the maintenance dose, the endpoint of a structured titration, not a flat dose given from day one.

The titration pathway matters because the GI side effects of semaglutide (nausea, diarrhoea, indigestion, and stomach discomfort are the most common) tend to be sharpest when the dose rises. Moving up slowly gives the body time to adjust. The licensed steps for Wegovy are 0.25 mg, then 0.5 mg, then 1.0 mg, then 1.7 mg, and finally 2.4 mg, each held for roughly four weeks before the prescriber reviews whether to continue titrating. A useful minute-long habit: before each new pen, check the dose printed on the label matches what your prescriber recorded at your last review. Mismatches are rare but worth catching early.

In April 2026, the MHRA went further, approving a dedicated single-dose 7.2 mg Wegovy pen for adults with a BMI of 30 or above. Trial data at this higher dose reported average weight loss of around 20.7% over 72 weeks, narrowing the gap with tirzepatide results. The 7.2 mg pen is a maximum dose for those who have already completed the lower titration steps; 0.25 mg remains the starting point.

Why the 0.25 mg starting dose exists, and what it is not for

One of the most common points of confusion around semaglutide dosage is the purpose of the first few weeks. The 0.25 mg dose is there to let your system settle. It does not produce meaningful weight loss on its own, and that is by design. If you are curious about what 0.25 mg actually looks like when drawn in a syringe, our guide to reading 0.25 mg semaglutide on a syringe explains the markings in plain terms.

The prescriber's decision about whether to move from one step to the next is based on tolerability, not just the calendar. If nausea or vomiting at a given dose is still significant after four weeks, a prescriber may recommend staying at that level longer rather than pushing upward. This is one of several reasons the dosage schedule is personalised rather than uniform. The NHS semaglutide patient information page provides a clear overview of common side effects and what to watch for at each stage.

For a broader look at how Wegovy's full dose range fits together, the Wegovy doses overview walks through each step and what the clinical guidance says about them. There is also a practical semaglutide syringe dosage conversion chart that can help when switching between presentations.

Semaglutide dosage in context: what a prescriber weighs up

The dose written on your prescription reflects more than your starting BMI. A prescriber considers your full medical history, any other medicines you take, whether you have conditions such as a history of pancreatitis or certain thyroid problems, and how well you have tolerated each previous step. Under the licensed indication, Wegovy is appropriate for adults with a BMI of 30 or above, or 27 or above alongside a weight-related condition such as high blood pressure or sleep apnoea. Lower BMI thresholds apply for some ethnic backgrounds under UK clinical guidance.

Semaglutide for weight management is not the same medicine as Ozempic, even though both contain semaglutide. Ozempic carries a UK licence for type 2 diabetes, at lower doses, and is not licensed for weight loss. The distinction matters because the dosage schedules and licensed indications differ entirely. If you have landed on this page wondering about semaglutide dosage more broadly, or specifically about the maximum semaglutide dose available in the UK, those pages go into more depth on each.

For context on what treatment costs privately in the UK, our Wegovy cost guide covers what is typically included in a private prescription price and what questions are worth asking any provider. When you are ready to talk through your specific situation, speak to our prescribers through a free consultation, a real clinician reads every assessment the same day.