When Wegovy Stops Working: What the Evidence Tells Us

What the trial data actually showed about long-term response

The STEP 1 trial (68 weeks, over 1,900 adults with obesity and no diabetes) found an average body-weight reduction of around 15% at the 2.4mg maintenance dose, as published in the New England Journal of Medicine. That headline figure is often read as a steady, continuous drop. In practice, the weight-loss curve is steepest in the first four to six months and then flattens. Many participants in the trial reached their lowest weight well before week 68, then largely maintained it rather than losing further.

This shape is not a flaw. Semaglutide works primarily by reducing appetite and slowing gastric emptying, and the body adapts. Your resting metabolic rate falls as you lose mass, a biological counter-response, not a sign the medicine has switched off. The NHS medicines page for semaglutide describes expected effects in plain terms, and your prescriber can set more realistic expectations about what that second six months of treatment typically looks like versus the first.

The distinction between a genuine plateau and the medicine simply doing less than you hoped matters enormously for what happens next. Knowing precisely how to tell whether Wegovy is working (weight, waist measurement, appetite signals, energy levels) gives you and your prescriber something concrete to discuss.

The common reasons Wegovy appears to stop working

Three patterns account for most cases where people feel Wegovy is no longer working, and they are quite different from each other.

The first is metabolic adaptation, described above. Your body defends a lower weight more actively than it defended the higher one. Appetite-suppression signals from semaglutide are competing with a stronger counter-signal. If you are wondering whether this means the medicine has permanently lost its effect, our page on whether Wegovy stops working separates the genuine ceiling effects from the temporary adaptation most people experience. This is not a reason to stop treatment; it is often a reason to stay on it.

The second is behavioural drift. The appetite suppression Wegovy provides can feel so reliable early on that people gradually relax the dietary changes that amplified its effect. Portion sizes creep up. Exercise falls away. Protein intake drops. None of this is a character failure; it is a normal long-term pattern. Research consistently shows that combining GLP-1 treatment with structured activity improves outcomes. There is detailed guidance on how exercise interacts with Wegovy that is worth revisiting if this feels familiar.

The third, and most practically addressable, is dose. If you are not yet at the 2.4mg maintenance dose, the plateau may simply reflect a sub-optimal dose for your biology rather than a ceiling effect. Understanding when Wegovy starts working and what the early dose stages feel like can help you judge whether you are still in the build-up phase or have genuinely reached a maintenance ceiling. Equally, the approved 7.2mg semaglutide dose (a higher maintenance option approved by the MHRA in early 2026) may be relevant for some patients. Whether that applies to you is a clinical question, not one answered by reading about it online.

When to talk to your prescriber, and what a productive conversation looks like

A genuine stall after six months at the full maintenance dose, with no change in weight and no measurable improvement in appetite control, is the clearest trigger for a clinical review. NICE's guidance on semaglutide (TA875) notes that if less than 5% weight loss has occurred after six months on the maintenance dose, continuing treatment should be reconsidered. That threshold is a clinical benchmark, not a verdict on you personally.

Before that conversation, it helps to bring something concrete: a weight log, a record of how your appetite has changed, and an honest account of what your eating and activity patterns have looked like lately. Prescribers find this far more useful than a general sense that things have slowed down. For a fuller treatment of the plateau question specifically, our page on why weight loss stops on Wegovy goes into the physiology in more depth.

Some people in this situation are good candidates for a switch to a different licensed treatment. Tirzepatide, the only dual GIP and GLP-1 receptor agonist licensed in the UK, activates two appetite-related pathways rather than one, and the SURMOUNT-5 head-to-head trial found it produced greater average weight loss than semaglutide 2.4mg over 72 weeks. Our overview of semaglutide as a treatment sets out how it works, which can be a useful reference point when discussing whether an alternative might suit you better. Whether that is appropriate for you depends on your health history, your current dose, and factors only a prescriber can weigh up. You can read a broader overview of your licensed weight-loss treatment options to frame the question before your consultation.

Timing matters in practice too. If your review falls near a bank holiday, a December break, or the run-up to payday when routines shift, try to schedule it slightly ahead of those disruptions so any clinical change can be monitored cleanly.

If you are considering a change in treatment

Switching, stopping or adjusting a prescription weight-management medicine is a clinical decision. You should not stop Wegovy abruptly without prescriber guidance; the NICE appraisal TA875 addresses duration and stopping criteria in its recommendations chapter. You should equally not increase your dose independently, request a specific alternative based on cost alone, or source a different medicine from a seller you cannot verify on the GPhC pharmacy register.

At nume, every prescription is reviewed personally by a GPhC-registered Independent Prescriber before it is issued. There are no algorithms making those calls. If you are already a patient with us and feel your treatment has plateaued, our prescribers are the right people to contact first. If you are new to us, you can start a free consultation and our clinical team will review your situation the same day. The nume clinical team is available for aftercare seven days a week.