Not Losing Weight on Wegovy 0.5mg? What the 0.5mg Dose Is Actually For

You've been injecting every week and nothing is shifting yet

Picture this: you ordered Wegovy, it arrived next working day, you've done three or four injections at 0.5mg, and the number on the scales is essentially where it started. Maybe it's moved half a kilogram, maybe not even that. You're wondering whether something is wrong with you, or with the medicine.

Nothing is wrong. The Wegovy dose schedule (confirmed in the prescribing information on the Medicines and Healthcare products Regulatory Agency's eMC (medicines.org.uk)) starts at 0.25mg and moves to 0.5mg after four weeks. Both of these early steps are there to limit the gastrointestinal side effects that semaglutide can cause. Nausea, loose stools, bloating: the lower doses reduce how sharply those hit. The appetite-suppressing effect of semaglutide grows as the dose rises, so at 0.5mg you're receiving a fraction of what the licensed maintenance dose delivers.

There's a useful way to think about it. A new medicine arriving in your system at a low dose is like a furnace being lit at the lowest setting. The mechanism is running; the heat comes later. Patience at this stage isn't passive, it's the right clinical approach. Our overview of how Wegovy doses are structured explains the full titration ladder if you want to see the whole picture.

What the clinical evidence shows about weight loss at low versus high doses

The STEP 1 trial (published in the New England Journal of Medicine) is the key evidence base for Wegovy. It ran for 68 weeks at the 2.4mg maintenance dose and found an average body-weight reduction of around 15%. That figure comes from participants spending most of the trial at or near 2.4mg, not from the weeks they spent at 0.5mg.

The reason is straightforward: semaglutide works partly by slowing how quickly food leaves your stomach and partly by acting on the areas of the brain that regulate hunger. Both effects scale with dose. At 0.5mg, appetite reduction is measurable but modest; the real behavioural shift (finding a large meal satisfying after a small portion, losing interest in food between meals) tends to become noticeable somewhere around the 1mg to 1.7mg range for most people.

If you're curious what to expect as things progress, the detail on what weight loss at the 0.5mg stage typically looks like and separately what 1mg tends to produce give you a realistic frame. The headline number from the trial is real, it just isn't earned at 0.5mg.

What can slow things down even further at this stage

Several things can compound the low-dose effect and make 0.5mg feel completely inactive.

Stress and poor sleep both blunt appetite regulation independently of any medicine. If you started Wegovy during a busy period (the run-up to a school holiday, a work deadline, the weeks after payday when social eating picks up) your context may be working against the early dose. That's not a failure; it's timing.

Some people find that GI side effects at 0.5mg, particularly nausea, lead them to eat differently: smaller meals that happen to be calorie-dense, or avoidance of vegetables in favour of plainer foods. Without noticing it, total calorie intake barely changes. Wegovy works best alongside genuine reductions in intake and increased movement, the licence itself specifies a reduced-calorie diet and increased physical activity as part of treatment, as the NHS semaglutide information page makes clear.

Water retention can also mask fat loss on the scales for a few weeks, particularly if diet composition has changed. The scale is one signal, not the whole picture. Body measurements, how clothes fit, and energy levels all matter. If the absence of loss genuinely concerns you, the right conversation is with your prescriber, not with a forum.

What happens at your next dose increase, and when to flag a concern

Your prescriber will move you to 1mg after roughly four weeks at 0.5mg, assuming it's been tolerated reasonably well. From there, the path through what 1mg tends to deliver and eventually toward 2.4mg (or the newer 7.2mg dose, subject to clinical assessment) builds progressively. The most meaningful changes happen in the middle and later dose steps.

The question worth asking if you're still not losing weight after reaching 1.7mg or 2.4mg is different from the question you're asking now. NICE guidance (TA875) recommends reviewing whether to continue if less than five percent of body weight has been lost after six months at the highest tolerated maintenance dose. That's a six-month review at a therapeutic dose, not a four-week review at 0.5mg. Our page on weight loss at 2.4mg covers what that stage typically produces.

That said, if you notice anything concerning (severe stomach pain, persistent vomiting, signs of an allergic reaction) that's a reason to get medical help promptly, regardless of which dose you're on. The full Wegovy treatment guide covers side effects and warning signs in more depth. And if you haven't started yet and are weighing up your options, speaking to our prescribers is a good place to begin.