Semaglutide Dosage: What the Evidence Says About the UK Schedule

What the STEP 1 trial established about effective semaglutide dosing

The most cited evidence for semaglutide's weight-management dosage comes from the STEP 1 trial, published in the New England Journal of Medicine. Over 68 weeks, adults with obesity using a 2.4 mg weekly dose alongside lifestyle changes lost an average of roughly 15% of body weight, compared with just under 3% in the placebo group. The trial established 2.4 mg as the target maintenance dose and demonstrated that the gradual escalation schedule (starting low and increasing slowly) reduced dropouts caused by nausea and other gastrointestinal side effects. That four-step ladder was subsequently reflected in the Wegovy UK licence and remains the starting point for prescribers today.

For readers researching how the full semaglutide dosage chart maps out week by week, the short answer is: 0.25 mg → 0.5 mg → 1.0 mg → 1.7 mg → 2.4 mg, each held for roughly four weeks before the prescriber considers moving up. The pace matters. Jumping steps to reach the maintenance dose sooner is not recommended; the evidence base was built on this specific titration rhythm.

Since January 2026 the picture has expanded further. The MHRA approved a 7.2 mg maintenance dose for adults with a BMI of 30 or above, supported by trial data reporting average weight loss of around 20.7% over 72 weeks at that higher dose. A dedicated single-dose 7.2 mg pen was subsequently approved in April 2026. Availability of this higher dose is confirmed at consultation, not assumed.

Semaglutide dosage in ml: why the number rarely appears on a prescription

Patients occasionally search for their semaglutide dose expressed in millilitres, particularly if they have encountered online discussions about compounded or raw peptide preparations. With licensed Wegovy pens in the UK, this figure is largely irrelevant in clinical practice. The pen is pre-filled and pre-set; the injection delivers the prescribed milligram dose without any measuring or drawing up. The volume in the barrel changes as pens move through the dose range, but a patient never handles that calculation.

The reason this matters: sources offering semaglutide as a powder to be reconstituted and self-dosed in millilitres are not operating within the licensed UK supply chain. The NHS medicines page for semaglutide describes the licensed presentation as a pre-filled injection pen. A prescriber should set and review every dose; self-titrating a reconstituted compound introduces errors that a factory-calibrated pen eliminates by design. If you have seen references to raw semaglutide dosage figures and are unsure what they mean, our page on raw semaglutide dosage explains the context.

Worth noting plainly: buying semaglutide without a prescription from an unverified seller is unsafe and illegal in the UK. The MHRA has seized large quantities of fake weight-loss pens, some containing incorrect or contaminated substances. Verifying a pharmacy on the GPhC register before ordering is the single most useful check a patient can do.

Who the licensed semaglutide dosage applies to, and where it starts

The UK licence for Wegovy covers adults with a BMI of 30 or above, or 27 to 29.9 with at least one weight-related condition such as high blood pressure, raised cholesterol or obstructive sleep apnoea. Lower BMI thresholds apply for some ethnic backgrounds under UK clinical guidance. A prescriber assesses the whole picture before recommending a starting dose; BMI alone does not determine suitability.

Treatment always begins at 0.25 mg, regardless of how far someone plans to escalate. This is not a therapeutic dose in the usual sense, its job is to acclimatise the body to semaglutide's GLP-1 receptor activity before any meaningful weight-effect dose is reached. Patients sometimes find this frustrating; understanding why the lower Wegovy doses exist makes the timeline easier to follow.

Semaglutide is not licensed for use in pregnancy, breastfeeding or in people trying to conceive, and it is not recommended for anyone under 18. People with a history of medullary thyroid carcinoma, MEN2 syndrome or certain gastrointestinal conditions should discuss this with a prescriber before starting. For non-diabetic adults specifically, the dosage considerations are covered in more detail on our page about semaglutide dosage for weight loss in people without diabetes.

At nume, every consultation is personally read by a GPhC-registered Independent Prescriber. If treatment is clinically suitable, the pen is dispatched the same day for free next-working-day delivery by DPD, it arrives in plain, unbranded packaging, with the Patient Information Leaflet inside the box and the dose your prescriber has set ready to go. Seeing how people access treatment through a regulated private pharmacy is part of checking eligibility for our weight-loss treatments.

Common side effects at each dose stage, and what to watch for

Gastrointestinal effects are the most frequently reported side effects of semaglutide across all dose levels: nausea, loose stools, constipation, reflux and belching tend to be most noticeable in the first one to two weeks after starting or increasing the dose, then ease for most people. At higher doses the intensity can return briefly before settling again. Fatigue, headache and dizziness are also reported, particularly in the early weeks.

One important signal to know at any semaglutide dosage level: severe, persistent stomach pain that spreads to the back (with or without vomiting) warrants prompt medical assessment, because acute pancreatitis is a known, if infrequent, side effect highlighted by the MHRA in a Drug Safety Update in January 2026. Reporting unexpected or serious side effects through the Yellow Card scheme helps regulators monitor the medicine's safety profile across the population.

Gradual dose escalation is the main clinical tool for reducing side effect burden. Taking the injection on the same day each week, staying well hydrated and avoiding large fatty meals during the adjustment period all feature in standard clinical guidance. If side effects at a particular dose are not settling, a prescriber may recommend holding that dose for an extra four weeks rather than escalating. This is normal, not a problem, reaching a lower maintenance dose that is well tolerated consistently produces better results than a higher dose that someone cannot sustain. Reviewing how dose increases are managed is covered in detail on our semaglutide dosage increase page.