How to Start Semaglutide: What Actually Happens in the First Weeks

The moment most people get wrong before they even begin

There is a common assumption that the first pen is the one that does the work. People look up average weight-loss figures from clinical trials, do the arithmetic, and expect results within weeks. In practice, the 0.25mg starting dose is not a therapeutic dose at all, its job is to let your body adjust to a new mechanism rather than to suppress appetite meaningfully. The process of starting Wegovy is a slow build, and accepting that early makes the whole course less confusing.

The licensed titration schedule described in the Wegovy prescribing information moves from 0.25mg to 0.5mg after four weeks, then to 1.0mg, then 1.7mg, and finally to the 2.4mg maintenance dose, each step roughly four weeks apart, though your prescriber may extend any stage if your body needs longer. Some people reach maintenance in five months; others take a little longer. The NHS patient information for semaglutide confirms this stepped approach and explains what to expect at each level.

Injections are subcutaneous (just under the skin) and can go into the abdomen, thigh or upper arm. You rotate sites. The pen is pre-filled and pre-set; there is no measuring involved. Most people describe the injection itself as almost painless once they have done it once or twice. A quick look at the practical steps for taking Wegovy can help if the physical process feels daunting before you start.

Eligibility: who semaglutide is licensed for in the UK

The UK licence 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, type 2 diabetes, high cholesterol or obstructive sleep apnoea. Lower BMI thresholds apply for some ethnic backgrounds under UK guidance, 2.5 kg/m² lower for South Asian, Chinese, Middle Eastern, Black African or African-Caribbean backgrounds.

BMI alone does not settle the question. A prescriber also considers your medical history, any medicines you take, and contraindications such as a personal or family history of medullary thyroid carcinoma or MEN2. Pregnancy, breastfeeding and active plans to conceive are reasons semaglutide is not recommended; the same applies to anyone under 18. If you are already on treatment elsewhere and considering transferring, a prescriber at a regulated pharmacy will want to see evidence of your current dose before continuing at the same level.

It is worth being clear about one thing: Ozempic is also semaglutide, but it holds a UK licence for type 2 diabetes management rather than weight loss. The two are not interchangeable for this purpose. If weight management is your goal, Wegovy is the licensed route. You can read more about the broader semaglutide medicines available in the UK to understand how they differ.

For a sense of whether you might meet the criteria before a formal consultation, the NHS BMI calculator gives a straightforward starting point.

What to expect in the first month: side effects, appetite and adjustment

The most common early experiences are gastrointestinal. Nausea tends to arrive in the first few days after each new dose, peaks around day two or three, and usually fades before the next injection. Loose stools, constipation, indigestion and burping are all reported; fatigue and mild headaches appear less often. For most people, symptoms are manageable and noticeably better by the second or third week of any given dose level.

Eating smaller portions, avoiding very fatty or spicy meals in the first days after an injection, and staying well hydrated all reduce the severity for most people. These are not formal prescribing instructions (your Patient Information Leaflet and prescriber are the right sources for personal guidance) but they reflect what many people find helpful.

The appetite reduction tends to become clearer from the 1.0mg stage onward, though responses vary. Some people notice it from the first pen; others feel little change until later in the titration. The STEP 1 trial, published in the New England Journal of Medicine, found an average weight reduction of around 15% over 68 weeks at the 2.4mg maintenance dose, a figure that reflects the full course, not the first month. Patience with the titration phase is not a failure of the medicine; it is how the medicine works.

One symptom warrants immediate medical attention: severe, persistent stomach pain that spreads toward the back, particularly with vomiting, can be a sign of pancreatitis. The MHRA flagged this in a safety communication in early 2026 and advises stopping treatment and seeking urgent help if this pattern develops. Report any suspected side effects, including unexpected reactions, via the MHRA Yellow Card scheme.

Getting started through a regulated UK pharmacy

Because semaglutide is a prescription-only medicine, the process of beginning treatment is also a clinical one. The route through a regulated online pharmacy (one you can verify on the GPhC pharmacy register) begins with a consultation rather than a basket. At nume, a GPhC-registered Independent Prescriber personally reviews every consultation the same day; your identity and current weight are verified as part of that process.

If you are thinking about timing, there is practical detail on when to begin Wegovy relative to your circumstances, including considerations around surgery or planned pregnancy. For those wondering about starting semaglutide specifically for weight loss rather than another indication, the eligibility criteria and clinical review process are explained in full.

Once approved, treatment is dispatched the same day (for orders placed before 12pm, Monday to Friday) and arrives the next working day with DPD, in plain packaging. There are no subscriptions; each repeat supply is reviewed clinically before it goes out. Our weight-loss treatment overview covers the broader options available if you are still deciding which medicine suits your situation best.

If you are ready to see whether semaglutide is the right fit for you, check your eligibility with a free consultation and a prescriber will review your answers the same day.