Wegovy 0.25 mg/0.5 ml: what the starting dose actually does

Your pen has arrived. You're wondering why the dose feels so small.

It is a fair question. You have read about Wegovy producing substantial weight loss in clinical trials, and then your first pen turns up labelled 0.25 mg. The number can feel anticlimactic.

The reason is straightforward. Semaglutide (the active medicine in Wegovy) slows the movement of food through the stomach and acts on appetite-regulating pathways in the brain. That combination is powerful, and starting too high too quickly can make nausea, vomiting and other gastrointestinal symptoms considerably worse than they need to be. The 0.25 mg starting dose gives your gut time to settle into the new rhythm before the dose climbs.

Think of these four weeks as a calibration period. The NHS describes the 0.25 mg phase as a tolerability dose in its semaglutide guidance for patients, and the prescribing schedule makes clear that 0.25 mg is not intended as a maintenance dose, it is a starting point. Most people do not notice dramatic appetite suppression at this level, and that is expected. You are not doing anything wrong.

One practical note on routine: the injection is easiest to build into an existing weekly habit. Many people keep their 0.25 mg/0.5 ml Wegovy pen in the fridge door and link the injection day to something that already happens on that day, a weekend walk, a regular GP appointment, whatever is fixed in your week. That kind of anchor tends to reduce missed doses better than relying on memory alone.

How the 0.25 mg/0.5 ml pen fits into the full Wegovy titration schedule

Wegovy's licensed titration ladder has five rungs. After the initial four weeks at 0.25 mg, the dose steps up to the 0.5 mg/0.5 ml pen, then 1 mg/0.5 ml, then 1.7 mg, and finally 2.4 mg, with roughly four weeks at each level before the next increase. The MHRA also approved a higher 7.2 mg maintenance dose in January 2026, though that sits well beyond the starting phase and is subject to separate clinical assessment.

Each step up is a clinical decision, not an automatic one. Your prescriber reviews how you have been tolerating the current dose before authorising the next. If side effects are still settling, staying at 0.25 mg or pausing a step is entirely reasonable, the schedule can flex. What it should never do is jump. Skipping steps without clinical input raises the risk of more severe nausea and makes it harder to distinguish a manageable adjustment reaction from something that needs attention.

You can read more about how doses change across treatment on our guide to the full Wegovy dose schedule, which covers what each rung is trying to achieve and what the titration process looks like in practice. Alternatively, if you are weighing up how Wegovy compares to other licensed options, the treatment overview sets out the landscape clearly.

The pen format at 0.25 mg is a pre-filled, single-use injection device. The injection volume is 0.5 ml, a standard subcutaneous dose administered once weekly into the abdomen, thigh, or upper arm. Rotate the site each week to keep the skin comfortable.

Side effects are most likely to surface in these first four weeks (here is what to watch for

The gastrointestinal effects of semaglutide) nausea, loose stools, constipation, indigestion, burping, and occasionally vomiting, tend to be most noticeable at the start of treatment and after each dose increase. For most people, they settle within a few days to a couple of weeks as the body adapts. Eating smaller portions, avoiding high-fat meals and staying well-hydrated can all help.

Fatigue, mild dizziness and headache are also reported in the early weeks. Injection-site reactions are possible; rotating sites helps reduce them.

There are a few symptoms that warrant prompt medical attention rather than a wait-and-see approach. Severe, persistent abdominal pain that radiates to the back (with or without vomiting) should be assessed urgently, as acute pancreatitis is a known, if infrequent, side effect of GLP-1 medicines. The MHRA issued a Drug Safety Update on this in January 2026, reinforcing the importance of recognising the symptom pattern early. Signs of a serious allergic reaction, significant dehydration from repeated vomiting or diarrhoea, or any symptoms you find alarming should all prompt a call to a healthcare professional or 111 rather than waiting for your next review.

Any suspected side effect can be reported through the MHRA's Yellow Card scheme, a useful habit throughout treatment, not just at the start.

A question our prescribers hear most weeks is whether it is normal to feel almost nothing at 0.25 mg. It is. The absence of strong appetite suppression at the starting dose is built into the design of the schedule.

Who the 0.25 mg starting dose applies to, and how clinical assessment fits in

The licensed indication for Wegovy covers adults with a BMI of 30 or above, or a BMI of 27 to 29.9 alongside at least one weight-related health condition such as high blood pressure, raised cholesterol, obstructive sleep apnoea or type 2 diabetes. Lower BMI thresholds apply for some ethnic backgrounds under UK guidance. These are the criteria set out in the product licence, eligibility in practice is determined by a full clinical assessment, not BMI alone.

For private prescribing through a service like ours, the process begins with a free consultation reviewed by a GPhC-registered Independent Prescriber, a named clinician reads your answers, not software. Identity and weight are verified before anything is dispensed. If Wegovy is appropriate, treatment starts at 0.25 mg regardless of what dose you may have been taking elsewhere, unless a transfer assessment indicates otherwise.

NHS access to Wegovy sits within specialist weight management services under NICE guidance, where waiting lists can be long. Private treatment through a regulated pharmacy is the alternative for people who do not meet NHS criteria or prefer not to wait. If you want to understand whether you are likely to be eligible, you can check your eligibility with our prescribers, the consultation is free, with no obligation.

For a fuller picture of what Wegovy costs privately, the Wegovy pricing page covers what is included in a transparent private prescription and why the price varies by dose.