How long before Wegovy starts to work — and what to expect at each stage

The first injection is in; nothing dramatic has happened yet, is that normal?

You administered your 0.25mg dose, put the pen back in the fridge, and went about your day. By the evening, dinner felt a little less urgent. By the third day, you left food on the plate, not because you were trying to, but because you simply didn't want it. That quiet shift in hunger is usually the first signal that semaglutide is doing something. It does not arrive with a fanfare.

The 0.25mg starting dose is there to help your body adjust, not to produce immediate weight loss. Nausea, the side effect people worry about most, is significantly less likely at this level. Weight changes in the first month are often modest, half a kilogram to a couple of kilograms is typical. Some people lose more; some notice very little on the scales but feel fuller at every meal. Both are valid starting points.

A common misconception is that if the first few weeks feel unremarkable, the medicine is not going to work. If you are wondering how long till Wegovy starts working and whether early subtlety means it is failing you, the appetite change is the mechanism and the weight loss follows behind it. You can read about what that first day typically feels like on our day-one Wegovy guide.

Months two to six: when the timeline gets interesting

Each dose increase, roughly every four weeks, tends to sharpen the appetite-suppressing effect. Moving from 0.25mg to 0.5mg, then to 1.0mg, 1.7mg and eventually 2.4mg brings renewed periods of reduced hunger. This is by design. The titration schedule exists to minimise gastrointestinal side effects, nausea and loose stools being the most reported, while nudging the therapeutic effect upward steadily.

In the STEP 1 trial, published in the New England Journal of Medicine, adults taking semaglutide 2.4mg lost an average of around 15% of body weight over 68 weeks. The loss was not evenly spread across that time. Understanding how long before Wegovy starts working at its most effective helps set realistic expectations, since the steepest reduction happened between weeks eight and thirty-six, roughly months two to nine, and a plateau is common even before people reach the maintenance dose. Worth knowing in advance.

If you want a broader look at how Wegovy compares with other licensed options, our weight-loss treatment overview covers the landscape.

Why results slow down, and when that matters clinically

Around the four-to-six month mark, weight loss often decelerates noticeably. The body responds to a sustained calorie deficit by becoming more metabolically efficient, less energy out, appetite partially recovering. This is a recognised physiological response, documented across the clinical literature, and it happens with or without GLP-1 medicines. The medicine is still working; the body has simply adapted to its new weight.

NICE's guidance on semaglutide, set out in TA875, includes a review point: if someone has lost less than 5% of their body weight after six months at maintenance dose, continuing should be reconsidered clinically. This is a useful benchmark. It is also a reason why clinical oversight throughout treatment matters, not just at the beginning. A prescriber can review the full picture (dose tolerance, lifestyle factors, progress) in a way a bathroom scale cannot.

The higher 7.2mg dose, approved by the MHRA in early 2026, has shown stronger average weight reductions in trials, approaching roughly 20% over 72 weeks. Whether that dose becomes appropriate for a given patient is a clinical conversation; it is not automatically the next step for everyone who plateaus. Our full Wegovy guide covers the dose pathway in more detail.

The practical question: how long should you give it?

A fair assessment of whether Wegovy is working for you requires at least three months, ideally six. Many patients ask how long does Wegovy start to work in a meaningful way, and the honest answer is that the first month is largely about tolerability, with the second and third months, as the dose increases, being when meaningful weight change usually consolidates. Weighing yourself weekly at the same time of day, under the same conditions, gives a cleaner signal than daily readings, water retention and hormonal fluctuations create a lot of noise in day-to-day figures.

If you are considering switching from a different injectable, perhaps moving across from liraglutide, the adjustment period may differ; our guide on switching from Saxenda to Wegovy covers what that transition typically involves. And for a realistic sense of how quickly results build, the NHS medicines page for semaglutide sets out what to expect in plain language.

If you would like to explore whether Wegovy or another licensed treatment is the right fit for your situation, our prescribers review consultations the same day they arrive. Speak to our prescribers through a free consultation, no referral, no waiting list.