What Does 10 Units of Semaglutide Actually Mean?

Where the "10 units" figure comes from

The confusion is understandable. Insulin has been measured in units for decades, and anyone who has handled a 100-unit/ml insulin pen is used to drawing up small whole numbers. Semaglutide, though, is measured in milligrams, and in the UK the licensed Wegovy pen comes factory-set to one of a fixed sequence of doses. You do not draw anything up; you dial, inject, and the device stops automatically. So when someone asks about 10 units of semaglutide, they are usually either encountering the language of compounded semaglutide (sold, often illegally, outside the licensed supply chain) or misreading volume markings on a pen.

This distinction matters practically. If a seller is asking you to draw 10 units into a syringe from a vial, that product is not the licensed Wegovy formulation you can verify through a UK pharmacy. The MHRA has warned repeatedly about unlicensed preparations and counterfeit weight-loss injectables, you can report suspect products or sellers at the MHRA's Yellow Card scheme. The page on converting semaglutide volumes to units covers the maths of that translation if you need it, but the safest context for any injection is one where the pen has already done the measuring for you.

What the licensed dosing schedule actually looks like

The MHRA-approved Wegovy injection pathway starts at 0.25 mg weekly, a tolerability phase while the body adjusts to the medicine. The prescriber then moves patients through 0.5 mg, 1.0 mg, and 1.7 mg before reaching the 2.4 mg maintenance dose, each step taking roughly four weeks. In January 2026 the MHRA approved 7.2 mg as a higher maintenance option, and a dedicated single-dose 7.2 mg pen followed in April 2026. None of these milestones maps neatly to a round "10 units" figure in any standard concentration, which reinforces the point that the unit framing does not belong to the licensed product.

Evidence for the licensed doses is substantial. The STEP 1 trial, published in the New England Journal of Medicine, followed adults with obesity over 68 weeks and found an average body-weight reduction of around 15% at the 2.4 mg dose alongside lifestyle support. That figure, important as it is, tells you about a population, your own prescriber looks at your weight, health history and any other medicines you take before setting or adjusting a dose. A breakdown of the broader semaglutide evidence is on the semaglutide overview page.

Risks of dosing outside the licensed framework

Compounded or unlicensed semaglutide preparations (the context in which unit-based dosing most commonly appears) have no MHRA marketing authorisation and have not gone through the same quality, safety and efficacy review as Wegovy. Concentration can vary between batches, which makes a volume-based dose genuinely unpredictable. The NHS's patient information on semaglutide focuses on the licensed product precisely because that is what clinical guidance is built around.

Gastrointestinal effects (nausea, loose stools, and stomach discomfort) are the most common complaints with semaglutide, and they are most pronounced when a dose is too high relative to what the body has adjusted to. A prescriber titrating through the proper schedule can slow down if those effects are significant. Going straight to a high unit count from an unlicensed vial removes that safeguard entirely. If you are weighing up treatment options and the cost of licensed treatment is a factor, the Wegovy cost page puts the figures in context. Understanding what goes into a legitimate prescription (clinical assessment, ongoing review, genuine supply chain) helps explain why prices look as they do.

It is also worth flagging the practical side of timing: if you're planning to start treatment after payday or around a bank holiday, knowing that licensed pens need refrigeration and that delivery windows matter is useful. A prescriber can work with you on those logistics. That kind of joined-up care simply isn't available when medicine is sourced from an unverified seller offering unit-dosed vials.

What to do if your dose question is about licensed Wegovy

If you are already prescribed Wegovy and want to understand how your dose corresponds to volume markings on the pen, the Patient Information Leaflet that comes with the pen is the right reference, or contact the prescribing team directly. NICE's appraisal of semaglutide (TA875), available at nice.org.uk/guidance/ta875, sets out the clinical framework UK prescribers work within, including the criteria for starting, continuing and stopping treatment.

If you are not yet on treatment and are trying to work out whether semaglutide is appropriate for you, the relevant pages on Wegovy and general weight-loss treatment options give a fuller picture of eligibility and what to expect. Doses in the 15-unit semaglutide range, or questions about 25 units of semaglutide, often come from the same place, unlicensed-product contexts that sit outside the regulated UK framework. The clinical team at nume reviews every consultation personally and can answer dose questions in the context of your actual health picture. Speak to our prescribers if you'd like that conversation.