Your First Shot of Wegovy: What to Expect from Day One

What the 0.25 mg starting dose is actually doing

The STEP 1 trial, published in the New England Journal of Medicine, recruited adults with obesity or overweight and at least one weight-related condition. Over 68 weeks at the 2.4 mg maintenance dose, participants lost an average of around 15% of their body weight. That headline figure does not belong to the first shot. At 0.25 mg, semaglutide occupies GLP-1 receptors gently, enough to begin slowing gastric emptying and reducing appetite signals, but at a level calibrated to minimise nausea. Think of it as a settling-in period rather than a therapeutic threshold.

What this means practically: do not expect to feel dramatically different after your first day on Wegovy. Some people notice a slight reduction in appetite within a few days; others feel very little change at 0.25 mg. Both responses are normal and neither predicts how well you will respond at higher doses. The prescriber who reviewed your case chose this starting point deliberately.

Your injection technique matters from day one, even if the dose is small. Clean the skin of your chosen site (abdomen, thigh or upper arm) with an alcohol swab. Pinch a fold of skin, insert the needle at a 90-degree angle and hold the pen in place for the full count your patient information leaflet specifies. Rotating sites prevents localised reactions over time.

Side effects in the first week: patterns from the clinical evidence

Gastrointestinal symptoms were the most commonly reported adverse events in the STEP 1 trial, and the NHS semaglutide guidance lists nausea, diarrhoea, constipation, vomiting, indigestion and burping as the most frequent. The important context: these effects were typically mild-to-moderate and most pronounced in the days immediately after starting or after a dose increase. Many participants found they settled within one to two weeks.

After your first shot, nausea (if it arrives) usually peaks around 12 to 24 hours later. Eating smaller, lower-fat meals and staying well hydrated tends to reduce it. The experience after the first Wegovy shot varies considerably from person to person, and the 0.25 mg level produces fewer GI complaints than any subsequent step.

There are symptoms that should prompt medical attention promptly. Severe, persistent stomach pain that radiates toward the back, with or without vomiting, can be a sign of pancreatitis, the MHRA issued a Drug Safety Update in January 2026 specifically highlighting this risk with GLP-1 medicines. Seek urgent help if that pattern appears. Signs of a serious allergic reaction, such as swelling of the face or throat or difficulty breathing, also require immediate emergency care. You can report any suspected side effect at yellowcard.mhra.gov.uk.

Timing your first shot and keeping the routine

When you take your first Wegovy shot matters less than picking a time you can repeat reliably each week. Most people choose a morning that suits their schedule, a weekend works well if your prescriber approves, because you have more time to monitor how you feel. The dose interval needs to stay as close to seven days as possible.

One practical check worth doing before you inject: look at the liquid inside the pen. It should be clear and colourless. If it appears cloudy, discoloured or contains visible particles, do not use it. That 20-second inspection takes no effort and is listed guidance in the patient information leaflet.

Storage matters for pen integrity. Wegovy pens should be kept refrigerated at 2–8°C. The exact room-temperature window and any other storage specifics are set out in your leaflet, always follow those rather than a general summary. If your pen arrived correctly packaged and refrigerated from a reputable online pharmacy, it should be in optimal condition.

What comes after the first injection

The titration schedule for Wegovy moves from 0.25 mg through 0.5 mg, 1.0 mg and 1.7 mg to the 2.4 mg maintenance dose, with roughly four weeks at each level. Your prescriber sets the pace based on how you tolerate each step, nobody should be pushing through persistent severe nausea to hit the next rung faster. There is now also a 7.2 mg dose approved by the MHRA (April 2026), though that is relevant only later in treatment and only for eligible patients.

For anyone exploring how Wegovy works more broadly, or comparing it with other options, understanding the full titration arc helps set realistic expectations. The weight reduction evidence in STEP 1 built over the entire 68-week period, steady, cumulative, not overnight. Semaglutide more generally, including what the molecule does at different dose levels, is covered in detail on our semaglutide overview.

If you are ready to start or are trying to understand whether Wegovy is right for your situation, a consultation is the place that question gets properly answered. It is free, reviewed the same day by a real clinician, and there is no commitment to proceed. Speak to our prescribers and get a clinical view of where you stand.