Wegovy units: what the numbers on your pen actually mean

You've seen a units number and your Wegovy pen says something different

Picture this: you're in a Facebook group or reading a forum post and someone writes "I'm on 50 units of semaglutide." You look at your pen, which says 1.0 mg. Are you on the same dose? Almost certainly not the same product at all.

Wegovy pre-filled pens don't use units. Each pen is factory-set to deliver a specific milligram dose (0.25 mg, 0.5 mg, 1.0 mg, 1.7 mg or 2.4 mg) and you simply press the button. There is no dial, no syringe, no conversion needed. The pen does the measuring. So if a number described in "units" is being compared to your pen's mg dose, the reference almost certainly relates to compounded or unlicensed semaglutide drawn into a separate syringe, where practitioners sometimes express concentration in units per ml as shorthand.

That distinction matters a great deal. Compounded semaglutide is not the same as the licensed Wegovy product, and the MHRA has flagged counterfeit and unlicensed weight-loss products as a significant patient-safety risk. If someone is telling you your dose in units and you are using a genuine Wegovy pen, the framing doesn't fit, and that mismatch is worth discussing with your prescriber before you act on it.

The semaglutide ml to units conversion page covers the arithmetic behind that calculation in full, if you need the technical detail.

How the Wegovy dose ladder actually works in the UK

The licensed schedule, described factually from the NHS semaglutide medicines page, starts at 0.25 mg for the first four weeks. This isn't a therapeutic dose in the sense of producing significant weight loss, its job is to let your digestive system settle before the medicine starts doing the heavier lifting. After that, doses step up approximately every four weeks: 0.5 mg, then 1.0 mg, then 1.7 mg, and finally 2.4 mg as the standard maintenance dose.

Since April 2026, a 7.2 mg single-dose pen has also been MHRA-approved for adults with a BMI of 30 or above, titrated up from the same 0.25 mg starting point. The titration schedule and whether that higher dose is appropriate for you is a clinical decision, not something to work out from a units converter. Availability of specific pen formats is confirmed at consultation.

One practical note: if your delivery lands around a bank holiday or you're ordering close to a monthly cut-off, your prescriber will consider where you are in the titration schedule before approving a repeat, another reason the clinical review before every order isn't a formality.

For a broader look at how semaglutide works as a weight-management treatment, the semaglutide overview page covers the mechanism, trial evidence and eligibility in detail.

When a units reference is actually about something else entirely

A third scenario: you've landed on this page because you searched for a specific number of units (5, 10, 15, 25) paired with semaglutide. Those searches usually relate to syringe-volume references for compounded products, and pages covering 10 units of semaglutide, 15 units of semaglutide or 25 units of semaglutide explain the arithmetic and context for those figures clearly.

What those pages also make clear is that the unit-based framing doesn't translate to a Wegovy pen. Genuine Wegovy pens are calibrated, sealed and single-use; you cannot adjust the dose, refill the cartridge or draw additional volume from them. That is a deliberate safety feature. A 2.4 mg Wegovy pen always delivers 2.4 mg. If you're trying to map a units figure onto that, you're probably looking at information written for a different product format.

Thinking about what Wegovy treatment costs in the UK as a private prescription? The Wegovy price comparison page lays out what the market looks like and what a legitimate private prescription should include.

What to do if you're genuinely unsure about your dose

Dosing uncertainty is one of the most common things our prescribers are asked about. The right answer is always: check your Patient Information Leaflet first, then contact your prescriber. Don't adjust your dose based on a units figure you've found online, the mismatch in measurement systems is exactly the kind of confusion that leads to errors.

At nume, every repeat order goes through clinical review by a GPhC-registered Independent Prescriber before dispatch. If something about your dose or your pen doesn't feel right, that review is the place to raise it, not a forum post. Our support team is available seven days a week, and dose questions are escalated to the prescribing team same day.

If you're not yet on treatment and want to understand whether Wegovy is the right option for you, our prescribers cover that in the free consultation. You can start your free consultation here and have your answers reviewed the same working day.