What actually happens in the 2nd week of Wegovy

The misconception that week two should already be 'working'

A lot of people arrive at their second week quietly disappointed. The scale hasn't shifted, or it's barely moved, and that can feel like the treatment isn't doing anything. It's a completely understandable thing to worry about, and it's worth letting go of, gently, because it's based on a misreading of what the starter dose is actually for.

The 0.25 mg weekly dose that begins Wegovy treatment exists primarily to reduce the chance of early GI side effects as your body adjusts to semaglutide. It is not the dose at which clinical weight loss was studied. The STEP 1 trial, published in the New England Journal of Medicine, produced its well-cited average weight reduction over 68 weeks at the 2.4 mg maintenance dose, a dose most people reach only after several months of careful titration. Expecting visible results in week two is like expecting a full journey from the first step out the door.

What IS happening in week two is real, even if it's invisible on the scales. Your GLP-1 receptors are being activated, gastric emptying is beginning to slow, and your appetite signals are starting to shift, subtly, often imperceptibly at first. Some people notice they feel slightly fuller after smaller meals. Others don't notice anything appetite-related yet at all. Both are normal at this stage.

Side effects in the 2nd week on Wegovy: what's typical

The most commonly reported side effects during the first few weeks are gastrointestinal. Nausea is the most frequent, followed by fatigue, constipation or loose stools, mild indigestion and occasional headache. These are well-documented in NHS guidance on semaglutide and tend to be most pronounced in the days following an injection, then ease before the next dose.

Week two can sometimes feel harder than week one, because the novelty effect (the sense of doing something new) has faded, but the side effects haven't fully settled. The practical things that help most people through: eating smaller portions, avoiding very fatty or spicy food around injection day, staying well hydrated, and not lying down immediately after eating. None of that requires a medical degree; most of it is common sense your stomach is asking for anyway.

One thing worth knowing: if nausea is persistent and genuinely affecting your daily life, tell your prescriber. It doesn't mean treatment has failed. It may mean the titration pace needs reviewing, or that some simple tweaks are needed. Stopping quietly and without support is rarely the right answer. At nume, our clinical team is available seven days a week specifically for moments like this, you can reach us through our contact page.

What to watch for that warrants medical attention

Most week-two symptoms are mild and transient. A smaller number of symptoms should prompt you to get medical help promptly rather than wait for them to pass. Severe, persistent abdominal pain (particularly if it radiates toward the back) needs same-day assessment, because acute pancreatitis is a known, though infrequent, side effect of GLP-1 medicines. The MHRA highlighted this in a Drug Safety Update for GLP-1 medicines; if in doubt, call 111 or go to your nearest urgent treatment centre. Signs of a serious allergic reaction (swelling of the face, lips or throat, difficulty breathing) need emergency care.

Dehydration is also worth taking seriously if vomiting or diarrhoea is prolonged. Keeping fluids up isn't just comfort advice, severe dehydration from GI illness can put additional strain on the kidneys. Any reaction that feels disproportionate, or that concerns you, should go to a clinician, not a forum. You can report suspected side effects directly to the MHRA at the Yellow Card scheme.

For a broader picture of how Wegovy tends to progress beyond these early weeks, the week-by-week Wegovy guide covers what most people experience from the first dose through to maintenance.

Looking ahead from week two

If week two feels underwhelming, week five often feels very different. By that point, many people on Wegovy have moved to 0.5 mg and are beginning to notice more consistent appetite changes. What you discover about week five of Wegovy often surprises people who were ready to give up in week two.

Week six tends to be when appetite suppression is more reliably felt, there's a fuller discussion of what happens at week six on Wegovy for anyone already thinking ahead. And if you're curious about costs and what private Wegovy treatment typically involves, the Wegovy cost guide covers the landscape honestly.

The second week is genuinely one of the harder ones to read. Side effects are still settling, results aren't yet visible, and the temptation to conclude it's not working is real. It isn't a clinical signal. It's a timing one. If you're further along and wondering what to expect next, our guide to Wegovy week 7 gives a clear picture of how things typically shift once you've cleared the earliest stage of titration. If you haven't yet started treatment and are considering Wegovy, a prescriber can walk through whether it's right for you, start a free consultation and a GPhC-registered prescriber will review your information the same day.