What happens in your first month on Wegovy?

Why does month one feel underwhelming on the scales?

Patients often describe a quiet frustration: their appetite has clearly changed, they are eating less without much effort, yet the number on the scale has barely shifted. That is not a malfunction. The 0.25 mg dose exists to let your digestive system adapt to semaglutide gradually, reducing the likelihood of nausea and other gastrointestinal discomfort. It is the lowest rung of the ladder for a reason.

At this dose, the pharmacological effect on appetite regulation is real but modest. GLP-1 receptor agonists work by slowing gastric emptying and increasing the signals that tell your brain you are full, but the full therapeutic effect builds as the dose increases across subsequent months. The STEP 1 trial, published in the New England Journal of Medicine, reported an average weight reduction of around 15% over 68 weeks at the 2.4 mg maintenance dose, that result reflects the whole treatment course, not the first four weeks.

So month one is largely about establishing the habit, building tolerance, and noticing early appetite shifts. Many people find this reassuring once they understand it. If you want a realistic picture of what the scales typically show by week four, the first-month weight loss data is worth reading before you start.

What side effects are most common in the first four weeks?

Gastrointestinal effects are by far the most reported in early treatment. Nausea is the one patients mention most, followed by constipation, loose stools, indigestion, and occasional burping. These tend to arrive in the day or two after an injection and ease off as the week progresses. For many people they diminish significantly by the third or fourth dose.

Fatigue and mild headaches are also reported, particularly in the first couple of weeks. Injection-site reactions (a little redness or tenderness at the spot) are common and brief. The NHS medicines page for semaglutide carries a clear list of what to watch for, and it is worth bookmarking alongside your Patient Information Leaflet.

Serious reactions in month one are uncommon but not impossible. Severe, persistent stomach pain that radiates toward the back (with or without vomiting) warrants urgent medical attention as it can be a sign of pancreatitis. Report any unexpected reaction to your prescriber promptly, and remember that the Yellow Card scheme at yellowcard.mhra.gov.uk allows patients to report suspected side effects directly to the MHRA.

A practical note on routine: many people find that keeping their pen at the front of the fridge door (in sight each week) makes it easier to stay consistent with the injection day.

How does the first month connect to the months that follow?

Think of month one as the foundation rather than the structure itself. If you tolerated 0.25 mg without significant difficulty, your prescriber will typically move you to 0.5 mg at week five, then 1.0 mg, 1.7 mg, and eventually 2.4 mg, each step giving your system another four weeks to adjust. A higher maintenance dose of 7.2 mg was approved by the MHRA in 2026 for adults with a BMI of 30 or above, though the titration to reach it takes considerably longer.

The pattern of weight loss tends to accelerate at higher doses. This is why comparing your month-one result to a friend's month-six result is not particularly meaningful. Progress through month two on Wegovy and into month three typically reflects dose increases rather than willpower differences.

People sometimes ask about switching or stopping early if month one feels slow. That decision belongs with your prescriber, not with a forum. The clinical picture, your current weight, how you tolerated the first dose, and whether you have any relevant health conditions all feed into that conversation. Our weight-loss treatment overview covers the broader context if you are still weighing up your options.

Is Wegovy the right treatment to start with?

That depends on your medical history, your BMI, and what a prescriber finds in your assessment. Wegovy is licensed in the UK for adults with a BMI of 30 or above, or 27 or above where at least one weight-related health condition is present, high blood pressure, obstructive sleep apnoea, and type 2 diabetes are among the conditions that can bring the threshold down. Lower BMI thresholds apply for some ethnic backgrounds under UK guidance.

It is a GLP-1 receptor agonist (single pathway), whereas tirzepatide, the active ingredient in Mounjaro, acts on two gut-hormone receptors. How those differences translate for any individual is a clinical question, not a marketing one. Our semaglutide information page covers the mechanism in detail if the science matters to you, and the frequently asked questions address some of the common queries about starting treatment.

If you are considering buying Wegovy online, it is worth reading about how to access it safely: prescription-only status means any supply reached without a clinical assessment falls outside the law, and counterfeit pens remain a real risk. A GPhC-registered pharmacy (verifiable at the GPhC register) is the benchmark worth checking before you hand over payment to any provider.

When you are ready to speak with a prescriber, a free consultation with our clinical team is the place to start.