Two weeks on Wegovy and no weight loss yet — here's what the trial data tells us

What the STEP 1 trial actually shows about early weeks

The STEP 1 trial, published in the New England Journal of Medicine, remains the clearest evidence base for semaglutide 2.4mg. Participants lost an average of around 15% of body weight over 68 weeks, roughly 16 months. That number is striking. What's less often quoted is how the loss was distributed across time: it accelerated as the dose rose through the titration schedule, and was modest in the earliest weeks at the lower starting doses.

At 0.25mg (the dose most people are on at two weeks) the pharmacological effect on appetite is limited by design. The dose escalation exists precisely because the body needs time to adjust before the therapeutic dose is reached. So a flat scale at two weeks is consistent with what the trial population actually experienced, not a departure from it.

The NHS medicines page for semaglutide echoes this: treatment is typically reviewed at months, not days. Expecting the full effect of a maintenance dose from a starter dose is the most common source of early disappointment with this treatment.

Why the scale can lie in week two specifically

Semaglutide slows gastric emptying. That means gut contents take longer to clear, and the weight that sits in your digestive system at any given moment may be higher than usual for the first few weeks. Add normal hormonal fluctuation, any change in how much water you're drinking, and the sodium shifts that come from eating differently, and the reading on any single morning can easily be 1–3 kg off your true trajectory.

The most practical thing you can do right now takes under a minute: weigh yourself on the same day each week, at the same time of day, before eating or drinking, with the same level of clothing. A single weekly reading compared week-on-week smooths out the noise that daily weighing amplifies. Many people who feel stuck at two weeks find a different picture when they look at a four-week trend rather than a two-day gap.

If you're finding early weeks harder to interpret, the week three experience covers what typically starts to shift as the dose-adjustment phase ends.

When to actually be concerned, and when to wait

There is a meaningful difference between no loss at two weeks (expected) and no loss at six months on the maintenance dose (worth reviewing). The NICE appraisal of semaglutide, TA875, notes that continuing treatment should be reviewed if weight loss falls below 5% after six months at the maintenance dose, not after two weeks at 0.25mg.

Side effects in the first fortnight, on the other hand, are worth tracking honestly. Nausea, loose stools and fatigue are common at the start and usually settle as the body adapts. They're not signs the medicine isn't working, often the opposite. But if side effects are severe enough to affect eating normally, that's a conversation for your prescriber rather than something to manage alone. Our frequently asked questions cover what's typical versus what needs attention.

What's not worth doing: searching for workarounds, skipping doses hoping to "restart", or comparing your week two to someone else's week six on a higher dose. The treatment works on a timeline, and that timeline is longer than a fortnight. If your situation is different (you transferred at a higher dose, or you're combining Wegovy with other conditions) a prescriber should review your specific picture. You can read more about the semaglutide evidence base and how doses are structured.

What's actually happening in your body at week two

Semaglutide works as a GLP-1 receptor agonist, it mimics a hormone your gut releases after eating, signalling fullness to the brain and slowing how quickly food leaves the stomach. At 0.25mg, that signal is relatively quiet. The appetite reduction that makes later weeks feel different (the meals left unfinished, the hunger that doesn't arrive between meals) typically becomes more noticeable as the dose increases.

This is worth knowing because it reframes what "working" looks like at two weeks. The treatment is working if your body is tolerating it. That's the job of week two. The weight loss follows the dose, and the dose follows the schedule.

For a fuller picture of how the treatment develops over the first month, the four-week semaglutide experience is worth reading alongside this, and if you want to hear real accounts of what people experience at six weeks on Wegovy when the scale hasn't moved, that page covers what's typically happening at that stage. And if you're still in the early stages of deciding whether Wegovy is the right fit, the Wegovy overview covers how the treatment works from the start, including a podcast episode where the evidence behind Wegovy is discussed in plain terms. When you're ready to speak to a prescriber, start your free consultation and a GPhC-registered prescriber will review your situation the same day.