How long does Wegovy take to work, and how long will you need it?

Week one to month three: you're waiting, and that's normal

You've just started your first 0.25mg pen. Nothing dramatic is happening yet, and that's by design. The opening weeks of Wegovy exist to let your body adjust to semaglutide, not to deliver weight loss. Most people notice some reduction in appetite or earlier fullness somewhere between week two and week four, but the scales often don't move much at this point.

The dose climbs roughly every four weeks (0.25mg, then 0.5mg, 1.0mg, 1.7mg, and finally 2.4mg) so the medicine's full effect builds gradually alongside that schedule. A question our prescribers hear fairly often is whether the first month is even doing anything. It is: your system is settling, side effects that might have hit hard at a higher starting dose are being dampened, and the therapeutic groundwork is being laid.

By month two or three, when you're closer to the mid-range doses, most people begin to see consistent weekly losses. That is when the treatment's appetite-suppression really starts to show in the numbers. If you're curious about how long Wegovy takes to work and what to expect at each stage, this page covers the first signals to watch for in more detail, alongside this page on the earliest signs of Wegovy working.

Month three to month six: where most of the weight loss happens on Wegovy

The STEP 1 trial (68 weeks, semaglutide 2.4mg versus placebo, published in the New England Journal of Medicine) found an average weight reduction of around 15% at the 2.4mg maintenance dose. That figure didn't arrive in week one. The steepest loss curves in the trial data tend to fall between roughly week 12 and week 36, once participants had reached and settled at the maintenance dose.

This is worth keeping in mind if you're partway through and wondering whether treatment is working. The six-month mark is also the checkpoint that NICE's guidance on semaglutide for weight management treats as a clinical review point: if less than 5% of body weight has been lost after six months at the highest tolerated dose, the guidance recommends reconsidering whether to continue. That review happens with your prescriber, not unilaterally.

For a fuller picture of how the weight-loss timeline unfolds week by week, our detailed results timeline page sets it out clearly.

Beyond six months: how long on Wegovy is long enough?

There's no single answer, and anyone who gives you one without knowing your situation is guessing. Wegovy's licence does not specify a maximum treatment duration, the medicine is approved for ongoing use in adults who meet the criteria and are responding to it. NICE's recommendation for NHS use does cap it at two years within specialist weight management services, but that restriction applies to the NHS commissioning pathway, not to the private licence.

What is clear from the trial evidence is that stopping Wegovy tends to reverse a significant proportion of the weight lost. Participants who discontinued semaglutide in extension studies regained most of the weight within about a year. That's not a reason to stay on it indefinitely without review, it's a reason to treat duration as a serious clinical question rather than a cut-off you set yourself at the start.

If you're planning around treatment (payday, a holiday, a Monday order before the 12pm cut-off) it's worth factoring in that each clinical review at nume happens before every repeat, so your prescriber has a fresh view of where you are at each stage. Thinking about what the overall cost of Wegovy over a treatment course looks like is a sensible part of that planning too.

You can read more about how the effects of semaglutide persist after stopping on our page on how long Wegovy lasts.

What affects how quickly Wegovy works for you specifically

The 15% average from STEP 1 is a population figure. Individual results spread around it, some people lose more, some less, and the pace varies. Factors your prescriber considers include your starting weight, whether you have conditions like type 2 diabetes (which typically blunts the response somewhat), how well you tolerate dose increases, and how consistently you're following the lifestyle changes the medicine is designed to support.

Gastrointestinal side effects (nausea, loose stools, indigestion) are common especially early on and at each dose step, and they can affect how quickly you progress through the schedule. They usually ease within a week or two of any given dose, but they're one reason the titration is slow by design. More detail on managing those early weeks is on our Wegovy overview page.

The broader picture of weight management treatment options at nume is also worth reviewing if you're still deciding which medicine is right for you, or speak to our prescribers directly by starting a free consultation, where your individual situation gets a proper look.