How to tell if Wegovy is working: signs, timelines and what to do next

The decision you are actually making: scale or appetite?

Most people come to this question carrying a specific worry: they have been injecting for a few weeks and the scales have not budged as much as expected. That worry is worth taking seriously, but the decision is not simply 'is it working or not' — it is 'which signal should I be trusting right now?'

Appetite change tends to come first. The way semaglutide works is by activating GLP-1 receptors involved in hunger signalling and gastric emptying, which means the gut slows down and the brain gets an earlier fullness signal. For many people the first noticeable shift is that they leave food on the plate, or find themselves less interested in the biscuits at 4pm. That is a real pharmacological effect, and it is worth logging it.

Weight on the scales follows, but it lags. Body weight fluctuates day to day by a kilogram or more depending on hydration, salt intake and where you are in your menstrual cycle. Weighing yourself every morning will produce a graph that looks like noise. Once a week, same morning, before eating, is enough. The pace of weight loss on Wegovy is gradual by design, the medicine is titrated slowly to keep side effects manageable, which means the therapeutic effect builds over months, not days.

The STEP 1 trial, published in the New England Journal of Medicine, found an average of around 15% body-weight reduction over 68 weeks at 2.4 mg. That is just over a year of consistent treatment. If you are at week three, you are not expected to be at 15% yet.

What counts as 'not working' and when does it matter?

There is a difference between 'Wegovy is not working yet' and 'Wegovy is not working for me'. The first is a timing issue. The second is a clinical one that deserves proper attention.

NICE's appraisal of semaglutide for weight management (TA875) includes a clear checkpoint: if a patient has not achieved at least 5% weight loss after six months at the maintenance dose, continuing treatment should be reconsidered. That is a formal clinical benchmark, not a rough guide. Your prescriber will look at it in the context of your starting weight, any dose changes, and whether anything else has been getting in the way.

Before reaching that six-month point, a few things can mimic a lack of effect. Doses are titrated slowly from 0.25 mg upward, and the lower doses are not expected to produce the full effect, they exist to let your body adjust. If you are still in the titration phase, you are not yet at therapeutic dose. You can read more about how long Wegovy typically takes to start working to set realistic expectations for your current stage.

It is also worth checking whether anything is actively working against the medicine: poor sleep, very high stress, or a diet that has crept back toward old patterns can all blunt the effect without the medicine itself being the problem. None of that means the medicine has failed, it means the full picture needs looking at with a clinician.

Signs to watch for beyond the scales

Weight loss is the headline, but it is not the only thing worth tracking. Some of the most useful signals are behavioural rather than numerical.

A question our prescribers hear regularly is whether side effects mean the medicine is working. The answer is: not necessarily, but common early side effects (nausea, a feeling of fullness after small portions, slightly slower digestion) are consistent with the medicine doing what it does at a physiological level. They are not proof of efficacy, but they are evidence the semaglutide is having an effect on gastric emptying and appetite signalling. If you want a fuller picture of what to look for, our guide on how to know Wegovy is working walks through the key signs in detail. If side effects are severe or persistent, that is a conversation to have with your prescriber rather than a reason to stop without advice.

Other positive signals worth noting: blood pressure trending down if yours was elevated, better sleep if your weight was affecting it, and clothes fitting differently before a significant number appears on the scales. Fat loss and muscle retention interact in ways that can mean body composition changes before overall weight does, particularly if you are active. There is useful context on that in our page about Wegovy and exercise.

If at any point you feel the treatment has plateaued or stopped responding, our page on what to do if Wegovy stops working covers the patterns behind that situation and the practical next steps worth understanding properly, rather than dismissing.

When to raise it with a prescriber, and what happens then

You do not have to wait for a formal review date if something feels off. The right point to get in touch is: if you have been on the maintenance dose for several weeks and have seen no change in weight or appetite; if side effects are interfering with daily life; or if you are unsure whether a dose increase is due.

At a review, a prescriber will typically look at your weight trend over time (not a single weigh-in), check whether the dose is appropriate, and ask about diet and activity. If you are on the titration schedule and have been making consistent progress, the plan usually continues. If progress has genuinely stalled, options include a dose increase, reviewing what is happening alongside treatment, or, in some cases, considering whether a different medicine might suit you better, there is a broader overview of weight-loss treatment options if you want to understand what alternatives exist.

Wegovy is a prescription-only medicine, and decisions about dose changes or continuing treatment belong with a clinician. If you started treatment elsewhere and want a second opinion, or if you are weighing up starting Wegovy for the first time, a prescriber at our clinical team can review your situation the same day. You can find out more about how we work on our about page, or go straight to start your free consultation.