The Wegovy 4-dose pen: one box, four weeks, one weekly injection

You've just opened your first Wegovy box and you're not sure what you're holding

The pen feels lighter than expected. There's no cartridge to swap, no dial to turn past four. That's by design. Novo Nordisk engineered Wegovy so that each pen arrives pre-filled and pre-set, ready for four injections at the same strength. You press, hear the click, and the dose is delivered. Then you recap and store it in the fridge door (yes, next to the milk) until the same day next week.

A common belief is that the pen somehow contains a month's worth of medicine in a single chamber you draw from separately each time. It doesn't work that way. The semaglutide is sealed inside in four equal portions, and the pen mechanism releases one portion per use. After the fourth injection the pen is empty and should go into a sharps container for safe disposal. Understanding that distinction matters practically: if a pen looks or feels different from the one you used last month, it may simply be a different strength, because each dose tier comes as its own pen format. The difference between Wegovy's pen strengths is worth reading before your first dose increase.

The NHS patient information for semaglutide, published on nhs.uk, covers how to use the pen correctly and what to do if a dose is missed, always defer to that leaflet and your prescriber rather than adjusting the schedule yourself.

Why your prescriber moves you through different pens over several months

Wegovy's titration schedule exists because the body needs time to settle into semaglutide. Most people start on the 0.25 mg four-dose pen. That first pen isn't producing the full weight-management effect, its job is to let your digestive system adjust gradually, reducing the chance that nausea or other gastrointestinal effects feel overwhelming from the outset. After four weeks on that pen, a prescriber will typically step you to the next strength, and so on up through 0.5 mg, 1.0 mg, and 1.7 mg, until you reach 2.4 mg as the standard maintenance dose.

The MHRA also approved a higher 7.2 mg maintenance dose in January 2026, initially using three 2.4 mg pens per week, followed by approval of a dedicated single-dose 7.2 mg pen in April 2026, relevant for people who have already reached 2.4 mg and whose prescriber considers a further step appropriate. Clinical trial data reported in the STEP 1 paper in the New England Journal of Medicine showed an average reduction of around 15% body weight over 68 weeks at the 2.4 mg maintenance dose. Results at individual doses within the schedule weren't the focus of that trial; total treatment duration and final maintenance dose were.

If you're wondering whether a higher dose will always produce greater results, that question has a more nuanced answer than most people expect. The relationship between dose and weight loss depends on individual response and tolerability, not just the number on the pen.

Practical things worth knowing before your next pen

Each time you move to a new strength, you are opening a new pen, not continuing an old one. Keep that in mind when storing a partially used pen alongside a next-strength pen you've just received; they look similar and should be clearly separated. Injection sites rotate between the abdomen, the front of the thigh, and the upper arm. You shouldn't inject into the same small spot twice in a row, and you should avoid skin that is bruised, tender, or scarred.

Side effects are most noticeable in the first days after starting a new pen or moving up a strength. Nausea, loose stools, and a reduced appetite are the most commonly reported. These tend to ease within the first week or two. Urgent symptoms (particularly severe stomach pain that reaches through to your back, with or without vomiting) should prompt immediate medical attention, as the MHRA has highlighted acute pancreatitis as a known, if infrequent, risk with GLP-1 medicines. You can report any suspected side effect at yellowcard.mhra.gov.uk.

For a fuller picture of how the four-dose format connects to the broader treatment journey, the breakdown of what one Wegovy pen contains covers the mechanics in more detail. And if you're thinking about what private treatment costs across a titration period, the Wegovy pricing page sets out the context honestly. Every repeat with nume goes back to a prescriber for review before dispatch, no automatic refills, no skipped checks.

When a four-dose pen isn't enough, or is the wrong pen entirely

Occasionally people reach out because they've used only two or three doses from a pen and something has gone wrong: the pen was dropped, stored incorrectly, or a dose was accidentally double-pressed. None of these are covered by changing to a different strength. What's covered is a conversation with your prescriber. At nume, aftercare is available seven days a week for exactly these moments, a question our clinical team fields regularly. The practical guide to using the Wegovy four-dose pen covers proper technique, storage handling, and what to do if you're unsure whether a dose was delivered.

It's also worth knowing that Wegovy is the weight-management licence for semaglutide. Ozempic is the same molecule but holds a type 2 diabetes licence, not a weight-loss one, the pens and doses are different and the two are not interchangeable. If you're unsure which treatment might suit you or want a prescriber to review your current schedule, you can start a free consultation with our prescribers and get a same-day clinical review.