Why Weight Loss Plateaus on Wegovy — and What the Trial Data Actually Shows

What the STEP 1 trial tells us about the shape of weight loss on semaglutide

The clearest starting point is the trial itself. In the STEP 1 study, published in the New England Journal of Medicine, adults with obesity taking semaglutide 2.4 mg weekly lost an average of around 15% of body weight over 68 weeks. That figure is an average across the whole period, and the curve is not a straight line. Most of the loss happens in the first six months. After that, the rate slows noticeably for many participants, and for some it plateaus for stretches of weeks or longer before progress resumes.

This is not a flaw in the medicine. It reflects a well-understood pattern: as body weight falls, metabolic rate adjusts downward, and the hormonal signals that semaglutide amplifies (particularly the GLP-1 pathway that reduces appetite and slows gastric emptying) work against a smaller calorie surplus than they did at the start. The gap between energy in and energy out narrows. Weight loss slows. For many people this happens around months four to seven, though the timing varies.

Knowing this matters because people who hit a Wegovy plateau at, say, month five often assume the medicine has lost its effect, and sometimes stop it. The trial data suggest that for most people, continued treatment at the right dose still produces meaningful results over the longer timeframe, and you can read more about what a Wegovy plateau involves and why it happens before deciding how to respond. Stopping prematurely tends to result in weight returning.

Why your specific plateau may have more than one cause

Not all plateaus share the same explanation. Several distinct factors can drive a Wegovy plateau, and they can overlap in the same person at the same time.

Dose is one of the most straightforward variables. Wegovy's licensed schedule runs from 0.25 mg up to 2.4 mg (and, as of 2026, to the newly approved 7.2 mg maintenance dose), titrated over several months. If you have not yet reached your maintenance dose, the appetite suppression you are experiencing is partial. Reaching the next dose step, under prescriber guidance, can restart loss that seemed to have stalled.

Adherence to the weekly injection schedule matters more than people expect. A pen taken a day late every week accumulates a significant drift over months. Similarly, Wegovy typically takes several weeks to reach full effect at each new dose, so a recent dose increase may simply need time to show up on the scales.

Diet composition shifts quietly over time for many patients. Early in treatment, the appetite suppression is dramatic and compliance with a lower-calorie pattern is almost effortless. Later, as the body adapts and hunger signals partially reassert themselves, old eating patterns can creep back in small ways that add up. Protein intake, in particular, tends to drift lower, and protein is central to preserving the lean muscle mass that keeps metabolic rate from falling further.

Finally, physiological adaptation is real. The body actively defends against weight loss through mechanisms that go beyond simple calorie arithmetic. This is not a willpower problem; it is biology. A good overview is available on the NHS semaglutide medicines page, which explains how the medicine interacts with these pathways.

What a prescriber review actually looks at, and why it matters before you change anything

If you have been weighing yourself every day, try stepping back. Daily fluctuation (fluid, food weight, the time of day) can easily read as a plateau when your monthly trend is still moving. A four-week average is more informative than a week's readings.

That said, if your weight genuinely has not shifted over six to eight weeks, a review with your prescriber is the right next move. They will typically look at where you are in the titration schedule, whether your current dose is the highest you have tolerated, and whether there are any adjustments to diet or activity that would help. Sometimes the answer is patience at the current dose; sometimes a dose increase is clinically appropriate; sometimes a referral to a dietitian for structured support is what actually shifts things. A prescriber can also assess whether any other medications you take are interfering with your results, certain antidepressants and steroids, for example, can work against weight loss.

If you are considering practical steps to move past a Wegovy plateau, start with a conversation rather than experimenting alone. Reducing calories sharply, adding intense exercise, or changing your injection schedule without clinical input can each backfire in different ways. For context on how Wegovy fits into the broader landscape of weight-loss treatment in the UK, our treatment overview sets out the options.

One question our prescribers hear regularly is whether switching medicine is the answer. People who find themselves plateauing on Wegovy and wondering what comes next may be candidates for tirzepatide, which works on two gut-hormone pathways rather than one and showed greater average weight loss in the SURMOUNT-5 head-to-head trial published in 2025. That is a clinical decision, not a consumer one, suitability depends on your health history, current dose, and how your body has responded so far. If you would like that conversation, our prescribers are available seven days a week. Before you book your morning appointment, it is worth jotting down your weight trend over the last eight weeks so the prescriber has something concrete to work with. That takes two minutes over a cup of tea and makes the review genuinely useful. Speak to our prescribers through a free consultation, reviewed the same day by a GPhC-registered clinician.