Your First Day on Wegovy: What to Expect and How to Prepare

Should you inject in the morning or the evening?

This is one of the first practical decisions you face, and the honest answer is that timing matters less than consistency. Pick a time of day you can stick to every week. Many people choose a morning after breakfast so any mild nausea arrives when they are already up and moving, rather than disrupting sleep. Others prefer an evening injection so that any discomfort passes overnight. There is no clinical evidence that one window is meaningfully better than the other for effectiveness.

What does matter is eating lightly around your injection day, particularly if nausea is new to you. A small, low-fat meal before or after the injection tends to sit better than a large one. Staying well hydrated throughout the day is consistently the piece of advice people say they wish they had followed from the start.

Your pen will have arrived in plain, unbranded packaging via tracked DPD delivery. Inside you will find the pre-filled Wegovy pen, which needs to come out of the fridge and reach room temperature for about 30 minutes before you use it. Store it back in the fridge between doses, always check the NHS semaglutide guidance or the Patient Information Leaflet for the exact storage window, since the manufacturer's instructions are precise and supersede any general advice.

What you will and will not feel in the first 24 hours

The semaglutide in Wegovy works by activating GLP-1 receptors involved in appetite regulation and gastric emptying. On day one at 0.25 mg, that activity is mild. Most people report nothing unusual. A minority notice nausea, a sense of fullness even after eating little, belching, or low-level fatigue, all documented in clinical trial data and consistent with what our prescribers hear regularly from patients in those early days.

These effects are almost always transient. The first injection's typical pattern is that any discomfort peaks around four to eight hours after injection and then gradually fades. If nausea is bothering you, ginger tea, cold water, and small meals tend to help. Lying down immediately after eating tends to make it worse.

Appetite suppression on day one is usually subtle. Do not measure the medicine's potential by how hungry or full you feel in the first 24 hours, and if you want a clear picture of what to expect on that very first day, our guide to day one of Wegovy walks through it in detail. The meaningful appetite shift that the STEP 1 trial participants experienced (an average weight reduction of around 15% over 68 weeks) built steadily with each dose increase, not overnight. How long Wegovy takes to work is a question worth reading before you set expectations for week one.

The decisions that shape your first week, not just your first day

Starting well on day one sets a pattern for the weeks ahead. A few things tend to make the biggest difference. First, protein. Wegovy reduces appetite considerably over time, and the risk is eating too little rather than too much, particularly too little protein, which supports muscle alongside fat loss. Starting to think about protein at every meal from day one, even while you are not yet very hungry, builds a habit that matters more as the dose increases.

Second, alcohol. Wegovy slows gastric emptying, which changes how quickly alcohol enters your bloodstream. The first week is a reasonable point to reduce or pause drinking, both for comfort and safety.

Third, activity. Light walking is fine from day one; vigorous exercise that dehydrates you on top of any GI side effects is worth spacing out carefully in the first few days.

If you are curious about what the full first week looks like as the medicine settles in, the first week on Wegovy covers the pattern day by day. And for a broader view of the treatment journey, the first month on Wegovy is worth bookmarking before your second injection.

When to contact a clinician rather than wait it out

Most first-day symptoms are mild and self-resolving. A few are not. Seek urgent medical help if you experience severe, persistent stomach pain that radiates to your back, this can be a sign of pancreatitis, which the MHRA flagged in a January 2026 Drug Safety Update as an infrequent but serious side effect of GLP-1 medicines. Symptoms of an allergic reaction (swelling around the face, difficulty breathing, rapid heartbeat) also require immediate attention.

Beyond urgent symptoms, any question about whether what you are feeling is normal is a reasonable one to raise with your aftercare team. At nume, prescriber aftercare runs seven days a week, so you do not have to wait until Monday to ask. You can also report any suspected side effect directly at the MHRA Yellow Card scheme.

If you have not yet started treatment and are still weighing your options, check your eligibility with our prescribers, there is no charge for the consultation.