Wegovy comes as one pen with four doses — here's what that means in practice

What the four-dose design means for how you use the pen

The Wegovy pen is built around a simple logic: one device, four weekly injections, one calendar month. When you press the pen against an injection site (the abdomen, thigh or upper arm) the device delivers a fixed dose and advances its counter. You cannot rewind it, split a dose or combine two weeks into one. Each of the four doses is identical in strength, which is exactly the point: your body receives the same amount every seven days while you are on that particular step of the titration ladder.

The injector locks permanently after the fourth dose, so there is no guessing whether a pen is empty. That is a safety feature as much as a practical one. What it also means is that if you accidentally trigger a dose at the wrong time, that dose is gone. The prescriber's guidance on injection timing is there to protect the four-week supply, not just to keep pharmacokinetics tidy. For more on how doses are structured across the full titration schedule, the Wegovy dose guide sets out each step with the clinical context behind it.

Injection sites should be rotated each week within the same region, or across regions if you prefer. The NHS medicines guidance for semaglutide covers the technique in detail and is worth reading before you administer your first dose, the NHS semaglutide page is a reliable starting point.

Storage: four weeks in the same pen means four weeks of discipline

The multi-dose format concentrates a month's treatment into one device, which makes cold chain continuity more consequential than it would be with single-use pens. Wegovy must be stored at 2–8°C, typically a fridge shelf, away from the freezer compartment and the fridge door where temperatures fluctuate. Between doses, the pen goes back into the fridge. How long it can safely sit at room temperature is defined precisely in the Patient Information Leaflet; this page cannot reproduce that figure because storage windows can change between product batches and the PIL is the authoritative source. The eMC listing for Wegovy is the place to verify the exact figures.

A question our prescribers hear regularly is what to do over a bank holiday weekend, a work trip or a holiday abroad. The honest answer is that planning matters more than improvising. If your re-order falls in a holiday week, ordering a few days earlier than usual avoids a gap. At nume, orders placed before 12pm on a working day are dispatched the same day once clinically reviewed, arriving the next working day via tracked DPD delivery, so a Monday order placed before the school run can comfortably resolve a timing clash. For full detail on what the structure of a Wegovy pen means logistically, that page breaks it down further.

If the pen freezes at any point, it must not be used, even after thawing. If you are unsure whether the cold chain has been maintained, contact your prescriber before injecting.

What happens if you miss a dose or lose a pen mid-course

Missing one of the four weekly doses is not automatically cause to abandon the pen, but timing matters. The Patient Information Leaflet gives specific guidance on what to do depending on how much time has passed since your scheduled injection, always refer to it first, and contact your prescriber if anything is unclear. The key principle is not to take two doses close together to compensate.

Losing a pen, or discovering mid-course that one has been damaged, is a more disruptive situation because it effectively interrupts your monthly cycle. A replacement pen requires a new clinical review and prescription, not just a re-order confirmation. That is a feature of being on a prescription-only medicine, not a quirk of the pharmacy, the prescriber needs to be satisfied that the replacement is appropriate given where you are in your programme.

There is a related question about what happens after just one dose: some people decide early in treatment that injection is not for them, or find side effects difficult in week one. The guidance on stopping a Wegovy pen after one dose addresses that scenario specifically. For a broader look at how the full programme fits together, the Wegovy overview covers the clinical picture from start to finish.

Titration, one pen at a time: why the design and the dose schedule align

The four-week pen and the roughly-four-week titration steps are not a coincidence. The schedule is designed so that one pen equals one dose level. You start on 0.25 mg (a tolerability step, not the therapeutic level) spend four weeks on it, then your prescriber steps you up to 0.5 mg, and so on through 1.0 mg and 1.7 mg before reaching the 2.4 mg maintenance dose. Each step is a new pen with a new strength. That clean correspondence between pen and step makes clinical re-review natural: your prescriber sees how you are responding before issuing the next strength, and if you want to understand how many doses are contained in one Wegovy pen before you start, that page gives a clear breakdown.

NICE's appraisal of semaglutide for weight management (TA875) sets out the clinical framework within which this titration happens on the NHS. For private patients at a service like nume, the same clinical principles apply: a GPhC-registered prescriber reviews your progress before each dose increase, checking that the titration is appropriate for you. The cost structure across the programme is explained on the Wegovy price page if you want to plan ahead financially. And if you are weighing up which treatment suits your situation, the weight-loss treatment overview compares the options available.

Check your eligibility by starting a free consultation with our clinical team, a real prescriber, not automated software, will review your details and help you understand the right starting point.