Semaglutide amounts for weight loss: what the evidence actually says

What the STEP 1 trial established about effective semaglutide amounts

The landmark trial that underpins Wegovy's UK licence enrolled 1,961 adults with obesity or overweight and at least one weight-related condition. Participants received 2.4 mg semaglutide weekly after a 16-week dose-escalation period. At 68 weeks, the average weight reduction was around 15%, roughly three times the response seen with lifestyle changes alone. These are group averages; individual results varied, and the trial ran alongside a calorie-reduced diet and increased activity.

That 15% figure shaped what NICE accepted as clinically meaningful. The NICE technology appraisal for semaglutide (TA875) recommends that treatment is reviewed if someone has not lost at least 5% of their body weight after six months at the maintenance dose, a threshold drawn directly from the trial's responder data.

A higher-dose option followed. The MHRA approved a 7.2 mg weekly dose in January 2026 and, in April 2026, a dedicated single-dose 7.2 mg pen. Trials of this higher amount reported average weight loss of approximately 20.7% over 72 weeks, narrowing the gap with tirzepatide's trial results. Worth knowing: the 7.2 mg option is licensed for BMI ≥30 only, not for lower thresholds.

The escalation schedule: why semaglutide doesn't start at the full amount

A question our prescribers hear most weeks is why the starting dose feels so small. The answer is almost entirely about tolerability. Semaglutide slows how quickly the stomach empties, which is central to its appetite-reducing effect, but at full therapeutic amounts from day one, that same mechanism produces nausea, vomiting and digestive discomfort in a significant proportion of people.

The weekly injection schedule runs: 0.25 mg for four weeks, then 0.5 mg, then 1.0 mg, then 1.7 mg, reaching 2.4 mg around week sixteen. Each step gives the body roughly a month to adapt. If side effects are difficult at any rung, a prescriber may recommend staying at that level longer rather than pushing on, this is a clinical decision, not a fixed timetable. For the oral tablet (Wegovy tablets, approved by the MHRA in June 2026 as the UK's first licensed oral GLP-1 for weight management), the schedule runs 1.5 mg daily up through 4 mg and 9 mg to a 25 mg maintenance dose, with at least one month at each level.

You can read more about how the different amounts compare in practice on the Wegovy dose guide, or see a broader overview of semaglutide for weight loss if you are earlier in your research.

Which semaglutide amounts apply to you, eligibility in plain terms

The licensed amounts for weight loss apply to adults with a BMI of 30 or above, or 27 to 29.9 alongside at least one weight-related 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. The dose you are prescribed is not chosen by you at checkout, a GPhC-registered prescriber reviews your full health picture and determines which amount is appropriate to start at, and when it is safe to increase.

On the NHS, access to semaglutide (Wegovy) follows strict criteria under NICE TA875 and is currently routed through specialist weight management services, with waiting lists that can stretch considerably. For those who do not meet NHS thresholds or prefer not to wait, private prescription through a regulated online pharmacy is the alternative, you can check what that route involves on the where to buy Wegovy page, or explore treatment options at nume if you would like to start a free consultation. Any legitimate private provider will still require a proper clinical assessment before issuing a prescription; the dose itself is never the patient's call alone.

One practical note on the oral tablet: because it is taken on an empty stomach first thing in the morning with a small amount of plain water, waiting at least thirty minutes before any food or drink, the 25 mg maintenance amount behaves quite differently day-to-day from a weekly injection. Neither format is inherently superior, the right choice depends on your lifestyle, preferences and clinical profile, all of which a prescriber can discuss with you. For a broader look at how semaglutide compares across formats, the semaglutide use for weight loss page covers the key differences.

Side effects across all dose levels are predominantly gastrointestinal. Nausea and loose stools are most common at the start of each new step and typically ease within one to two weeks. If you are curious about less-discussed effects, the Wegovy and sleep page addresses one that comes up more than you might expect. The NHS medicines page for semaglutide lists the full side-effect profile and explains when to seek medical help.