How to use Wegovy 0.25mg: what the starting dose actually does

What the licensed guidance says about the 0.25mg starting dose

The Wegovy prescribing schedule is set out in the Summary of Product Characteristics (SmPC), which the MHRA holds as the authoritative UK reference. The SmPC establishes 0.25mg as the mandatory starting point for all patients, regardless of body weight or how quickly someone wants to progress. There is no clinical shortcut past it. The reason is straightforward: semaglutide slows gastric emptying and acts on appetite-regulating pathways in the brain, and introducing it gradually gives the gut time to adapt. Starting at a higher dose without this adjustment period significantly raises the likelihood of nausea and vomiting in the first weeks.

The NHS medicines guidance for semaglutide confirms that the 0.25mg phase lasts four weeks before moving to 0.5mg, and that the full escalation ladder runs through 1.0mg, 1.7mg, and 2.4mg (or 7.2mg, depending on individual response and prescriber assessment). You can read the patient-level detail on the NHS semaglutide page. What this dose schedule also means is that the 0.25mg pen you receive is not a lower-strength product — it is the same device, the same weekly ritual, just the beginning of the process. Understanding that from the start tends to reduce frustration when the scales don't move much in week one.

For a broader look at how doses progress across the full Wegovy journey, the Wegovy doses guide covers each step and what to expect from it.

How to inject the 0.25mg pen: step by step

The Wegovy pen is a pre-filled, pre-set device. You do not draw up a dose or adjust anything. Each pen contains four weekly doses. The injection process follows a consistent sequence: choose your site, clean it with an alcohol swab, uncap the needle, press the pen flat against the skin at a 90-degree angle, hold the button until the click confirms delivery, and hold for a further six seconds before withdrawing. That pause matters, pulling away too quickly can mean some of the dose is lost.

Site rotation is practical advice, not optional. Injecting repeatedly into the same small patch can cause a build-up of fatty tissue (lipohypertrophy) that slows absorption. Your three options are the abdomen (at least a couple of centimetres from the navel), the outer thigh, or the upper arm. Many people find keeping a simple note (even just a sticky note on the fridge) useful for tracking which site they used the previous week. The pen should be stored in the fridge between injections, between 2°C and 8°C. For the exact room-temperature window if you need to travel, the patient information leaflet is the place to check, your prescriber or pharmacist can walk you through it.

For more detail on the physical mechanics of the device itself, the four-dose pen guide goes through the pen's design in depth.

Side effects at 0.25mg and how to manage the early weeks

The most common side effects during the 0.25mg phase are gastrointestinal. Nausea tops the list, followed by constipation, loose stools, indigestion and burping. These effects tend to be most noticeable in the 24 to 48 hours after each injection, and most people find they ease off as the weeks pass. Eating smaller meals, avoiding high-fat foods, and staying well hydrated all help. Fatigue and mild headaches are also reported by some people, particularly in the first two weeks.

Serious side effects at any dose are less common but worth knowing. Pancreatitis is a recognised risk with GLP-1 medicines: the MHRA's Drug Safety Update of January 2026 flagged acute pancreatitis as an infrequent but potentially serious effect, and the symptom to act on immediately is severe stomach pain that spreads to the back, particularly if it is persistent and accompanied by vomiting. If that happens, stop the injection and seek urgent medical help, do not wait for your next scheduled review. You can report any suspected side effect through the MHRA Yellow Card scheme.

There is also the question of what to do if a weekly injection is missed. The patient information leaflet sets out the guidance clearly, and your prescriber is the right person to ask if you are unsure, this is exactly the kind of practical question the nume FAQs and aftercare team are there to help with.

Choosing the right injection day and staying consistent

Semaglutide's half-life means it stays active in the body for roughly a week, which is why once-weekly dosing works. Picking a fixed day and sticking to it (a Tuesday morning before the school run, a Sunday evening as part of a routine) makes it far easier to stay consistent. The exact time of day does not matter clinically, but the day-to-day interval should be as close to seven days as possible. If you are new to the pen and want a walkthrough of each step, our guide on how to take Wegovy 0.25mg covers the process in detail. Injections can be taken with or without food, and at any point during the day.

Consistency also applies to the injection process itself. A reliable weekly ritual, same site rotation, same storage habit, reduces the chance of errors building up over months of treatment. As your dose increases over time, you may find it helpful to read our guides on how to use the Wegovy 0.5mg pen and, further along the schedule, how to use the Wegovy 1mg pen, so you know what to expect at each step before you get there. If you are wondering how 0.25mg fits into the bigger picture of what Wegovy can achieve, the Wegovy overview explains the full treatment context and the clinical evidence behind it. And for those at the very start of working out whether semaglutide is the right route, the weight-loss treatments page sets out all the options available.

If you have questions about starting Wegovy or about whether your situation suits the programme, our clinical team reviews every consultation personally. Speak to our prescribers through a free consultation, there is no obligation, and someone will read your answers the same day.