Is Wegovy any good — and what does the trial evidence say?

What the STEP 1 trial actually found, and why the numbers matter

The evidence for Wegovy starts with one of the most rigorous trials in obesity medicine. STEP 1, published in the New England Journal of Medicine, ran for 68 weeks across thousands of adults with obesity or overweight and at least one weight-related condition. Participants on semaglutide 2.4mg lost an average of around 15% of their body weight. Those on placebo lost about 2.4%. That gap is not a rounding error, it reflects a genuine pharmacological effect on appetite regulation and gastric emptying.

A common assumption is that injectable weight-loss medicines produce dramatic results for everyone who tries them. The reality is more nuanced. The 15% figure is an average; individual results varied, and some people in the trial lost considerably more. A smaller number lost less. What the data shows clearly is that, at population level, semaglutide works substantially better than diet and activity changes alone when both groups are given equivalent support. That is a meaningful clinical finding, not a marketing claim.

More recently, the MHRA approved a 7.2mg maintenance dose of Wegovy. Early trial data suggests average weight loss of around 20.7% at this higher dose, narrowing the gap with tirzepatide (Mounjaro). This approval, and the subsequent April 2026 clearance of a dedicated single-dose 7.2mg pen, signals that the evidence base for semaglutide continues to grow. If you want to understand how good semaglutide really is across the full dose range, that context matters.

Who Wegovy tends to work well for, the eligibility picture

Wegovy is licensed in the UK for adults with a BMI of 30 or above, or a BMI of 27 to 29.9 alongside at least one weight-related condition such as type 2 diabetes, high blood pressure, high cholesterol, or obstructive sleep apnoea. Lower BMI thresholds apply for some ethnic backgrounds under UK guidance. NICE's recommendation (TA875) goes further, it specifies use within specialist weight management services, for a maximum of two years, and for adults with a BMI of 35 or more (or the lower equivalent) alongside at least one comorbidity.

In practice, that means Wegovy is not a universal answer. It suits people for whom excess weight is genuinely affecting their health and who can engage with the diet and activity changes that maximise what the medicine does. The drug reduces appetite and slows how quickly food leaves the stomach; those effects are most useful when paired with a protein-adequate diet and some regular movement. It is less suited to people with certain gastrointestinal conditions, a history of pancreatitis, or specific thyroid conditions, all factors a prescriber checks before treatment starts.

If you are wondering whether your own circumstances fit, our weight-loss treatment overview sets out the full eligibility picture and what the consultation process covers.

Side effects and the question of whether Wegovy is worth it

No medicine worth taking has no side effects. Wegovy's most common ones are gastrointestinal: nausea, vomiting, diarrhoea, constipation, and indigestion are all reported, particularly in the first few weeks or after a dose increase. For most people these are temporary and mild-to-moderate. Slowing the dose titration, eating smaller portions, and staying hydrated helps considerably, a question our prescribers hear most weeks.

Rarer but more serious effects include acute pancreatitis. The MHRA issued specific guidance on this in January 2026, highlighting severe and persistent stomach pain that radiates to the back as a symptom requiring urgent medical attention. Gallbladder problems and allergic reactions are also documented. The NHS semaglutide medicines page carries a full list of side effects to be aware of.

Wegovy is not licensed for use in pregnancy or breastfeeding, and it is not recommended for anyone trying to conceive. It is not licensed for under-18s. These are not small print, they are decisions made at the prescribing stage, not after the fact.

On balance, whether Wegovy is genuinely good for you depends entirely on the individual. For people who qualify clinically and have struggled to achieve meaningful weight reduction through lifestyle changes alone, the evidence on whether Wegovy is good for weight loss suggests it can make a significant difference. For a broader comparison of how it sits alongside other options, see the case for and against Wegovy.

NHS access, private routes, and what to consider about cost

NICE recommended Wegovy in 2023, but access on the NHS remains tightly restricted to specialist weight management services, which often carry long waiting lists. The NHS pathway requires multidisciplinary support and limits treatment to two years. Not everyone who would benefit clinically meets the current commissioning criteria, and availability varies considerably by region.

Private prescriptions offer a faster route for people who are clinically suitable but either do not meet NHS thresholds or prefer not to wait. If you are thinking about the cost side of this decision, our Wegovy price guide explains what private treatment typically costs in the UK and what a legitimate price should include. Worth knowing: any provider offering Wegovy without a clinical assessment is not operating legally, this is a prescription-only medicine, and the prescription exists to protect you, not to create friction.

At nume, every consultation is reviewed personally by a GPhC-registered Independent Prescriber. If you are a good clinical fit, treatment is dispatched the same day and arrives the next working day in plain packaging. If you are curious about whether Wegovy could suit you, starting a free consultation is the most straightforward way to find out.