Taking Wegovy for the first time: what actually happens

The week your pen arrives and what to do before you inject

A plain, unbranded box turns up via DPD, tracked to your door. Inside: your Wegovy pen, stored cold in an insulated liner. Before anything else, move the pen to the fridge (2–8°C) and leave it there. Do not freeze it, and keep it away from the fridge's cooling element at the back.

Read the Patient Information Leaflet that comes with your pen before your first injection. Not skimming it — actually reading it. It covers the preparation steps, the injection sites (abdomen, thigh or upper arm, rotated each week), how to check the pen window, and what the liquid should look like. If anything in it raises a question, contact our team before you inject rather than after.

When you're ready, the pen is pre-filled and pre-set at 0.25 mg. There's no dialling or measuring. Clean the injection site with an alcohol swab, let it dry, then follow the steps in your leaflet. The needle is small. Most people find the process far less daunting than they'd imagined. Once the pen clicks and you've held it in place for the count the leaflet specifies, you're done for seven days.

For a detailed walkthrough of the injection itself, the first-time Wegovy injection guide covers technique step by step.

What the first few days on semaglutide actually feel like

Most people notice very little in the first week. The 0.25 mg dose is a tolerability measure, so a muted response is expected and normal. Some people feel mild nausea (usually a vague unsettled stomach rather than acute sickness) and a modest drop in appetite. Others feel nothing different at all and worry something has gone wrong. Both reactions are typical.

The side effects that tend to come up most often in the early weeks are nausea, loose stools, constipation and burping. They are generally linked to how much and how quickly you eat, so smaller meals eaten slowly, staying well hydrated and cutting back on high-fat foods can all make the adjustment easier. The semaglutide overview goes into more detail on managing the GI side of things.

The NHS medicines page for semaglutide lists the full side-effect profile with guidance on which symptoms need prompt medical attention. Know the ones that can't wait: severe, persistent stomach pain that spreads towards the back (seek help the same day), signs of an allergic reaction, or gallbladder pain. Those are not situations to monitor and report at your next review.

Tips for taking Wegovy for the first time are most useful when they're specific rather than general. Eat before you feel hungry rather than waiting until appetite signals arrive, because those signals will be quieter than you're used to. Protein and fibre at each meal reduce the risk of muscle loss as weight comes down. And drink more water than you think you need, constipation is far easier to prevent than to fix.

How the dose steps work over the coming months

The titration schedule moves in roughly four-week stages: 0.25 mg, then 0.5 mg, then 1.0 mg, then 1.7 mg, then 2.4 mg. Your prescriber reviews where you are before any increase, and the pace can slow if side effects make a faster schedule uncomfortable. Staying at a lower dose for longer is not a setback, it is the process working as designed.

Some people reach 2.4 mg with minimal difficulty. Others find 1.7 mg their ceiling for now. The aim is the highest dose your body tolerates well, because that's where the evidence (including the STEP 1 trial published in the New England Journal of Medicine, which found an average weight reduction of around 15% over 68 weeks) is strongest. The Wegovy treatment guide covers the full schedule in more detail.

The question of private treatment costs comes up early for most people starting out. If you want to understand how Wegovy pricing works in the UK before committing to a longer course, the Wegovy cost breakdown is worth reading alongside this guide.

If a prescription is declined after your consultation (which does happen when the clinical picture doesn't fit) the reasons Wegovy prescriptions are declined page explains what tends to come up and what your options are.

The first injection day: a plain timeline

Pick a day you can keep as your weekly injection day, a Tuesday or a Saturday, whatever fits your routine. Inject at broadly the same time of day each week, though Wegovy can be taken at any time, with or without food. Morning works well for people who want the routine anchored to waking up; evening works equally well for others. There is no single right answer here, but picking one and sticking with it makes it easier not to miss a dose.

On your first injection day: take the pen from the fridge, let it come to room temperature for a few minutes if it feels very cold, then follow the leaflet. Log the date somewhere you'll see it. Set a reminder for the same day next week. That's the routine for the weeks ahead, once weekly, same day, rotate injection sites. The timing guide for your first Wegovy dose goes into the detail of morning versus evening and what the evidence suggests.

If you have further questions after reading your leaflet, our FAQs cover many of the common ones, and our aftercare team is reachable seven days a week via the contact page. The first week is nearly always simpler than people expect. The weeks that follow are where the work happens.

If you haven't yet had a clinical assessment, you can start your free consultation with a prescriber from our team to see whether Wegovy is suitable for you.