What to Expect From Your First Injection of Wegovy

The pen arrives and you're standing in your kitchen wondering where to start

Your Wegovy pen comes refrigerated, usually in a plain unbranded box tracked to your door by DPD. Before you do anything else, read the Patient Information Leaflet inside. It is not optional reading. The leaflet tells you the exact room-temperature window the pen can sit outside the fridge, how to attach the needle, and what a correctly primed pen looks like. Our prescribers are asked, regularly, whether skipping the leaflet is fine. It is not.

Once you are ready, choose your injection site: the lower abdomen (at least 2 cm from the navel), the front of one thigh or the outer upper arm. Clean the area, let it dry, then hold the pen against your skin and press. The injection itself takes seconds. Many people who were nervous about self-injecting find, after the first one, that the anticipation was the harder part. A step-by-step guide to using the Wegovy pen for the first time covers each stage in more detail, including what the device feels like when the dose is complete.

Dispose of the used needle in a dedicated sharps container, not a household bin. A 1-litre sharps container is the right size for home use and meets clinical disposal standards. This is not a detail to improvise.

What the first few days after injecting actually feel like

Nausea is the most commonly reported side effect in the days following a first Wegovy injection. For some people it arrives within a few hours; for others it barely shows at all. Vomiting, loose stools, burping, constipation and mild reflux are also reported. These effects are usually at their most noticeable after the first dose or after a dose increase, and most people find they ease as the weeks go on.

Eating smaller meals and avoiding fatty or heavily spiced food in the first couple of days can help. Staying well hydrated is important, particularly if nausea is significant. The side effects following the first Wegovy injection are covered in more detail on a dedicated page, including when symptoms warrant a call to your prescriber.

A note on timing worth knowing: if severe stomach pain comes on and radiates toward your back, with or without vomiting, that is not a typical GI side effect. Get urgent medical help and tell the clinician you are on a GLP-1 medicine. In January 2026, the MHRA issued a Drug Safety Update specifically on acute pancreatitis as a known, infrequent but potentially serious risk with GLP-1 medicines. It is rare. Knowing it exists is still worthwhile. You can report unexpected side effects through the MHRA Yellow Card scheme.

What happens in the weeks after your first injection

The 0.25 mg dose runs for roughly four weeks. After that, a prescriber reviews your progress before stepping you up, typically to 0.5 mg. The titration continues at intervals until the maintenance dose is reached. How often Wegovy injections are given (and what the dose schedule looks like from start to maintenance) is explained separately.

Appetite changes are usually subtle at first. The medicine takes time to build; do not judge the treatment by week one. Some people notice that familiar hunger signals feel different within the first couple of weeks. Others notice nothing obvious until a dose increase. Both experiences are normal. What happens in the period following the first Wegovy injection goes into more detail on what to track and when to flag something with your clinical team.

If you are weighing up how Wegovy compares to other injectable options, the weight-loss treatment overview covers the licensed options side by side. And if cost is part of your thinking, Wegovy pricing in the UK explains what private prescriptions typically include and what to look for when comparing providers.

When to call your prescriber rather than wait it out

Most side effects in week one are unpleasant but not dangerous. Some signs are different. Contact your prescriber or seek urgent medical help for: severe abdominal pain that does not ease; signs of significant dehydration (very dark urine, dizziness, inability to keep fluids down); any symptoms of a serious allergic reaction (swelling of the face or throat, difficulty breathing); or low mood or thoughts of self-harm. These are not reasons to feel alarmed going in, but they are reasons to act if they happen.

If you are starting Wegovy and also take an oral contraceptive pill, discuss this with your prescriber before your first injection. GLP-1 medicines can slow gastric emptying, which may affect how the pill is absorbed. Starting semaglutide for the first time includes a summary of interactions and lifestyle adjustments that are worth reviewing ahead of day one.

A real clinician, not a triage algorithm, reads every consultation at nume before treatment is approved. If questions come up after you have started, our clinical team is reachable seven days a week.