How does Wegovy compare to other weight-loss medications?

Compared with other weight-loss medications available in the UK, Wegovy relies on GLP-1 receptor activation to lower appetite, while alternatives may block fat absorption or use tablet combinations that influence appetite and reward pathways. In comparative evidence, GLP-1-based therapies typically produce larger average weight reductions than older options when used with lifestyle support. That said, the “best” choice depends on clinical suitability, side-effect profiles, convenience (weekly injection vs daily tablets), and local commissioning: Scotland (SMC) and Wales (AWTTC) sometimes apply criteria that differ from those used in England.

Where Wegovy sits among NHS options

The NHS currently makes only a handful of weight-management medicines available, and access is tightly controlled. Orlistat has been prescribed for many years and works by reducing the amount of fat absorbed from food. More recently, GLP-1 receptor agonists such as semaglutide (Wegovy) have entered NHS pathways. Guidance from NICE describes semaglutide as producing greater average weight reductions than older medicines, which explains why interest and uptake have grown. Still, decisions about prescribing always depend on whether a medicine fits the individual’s needs, health profile, and eligibility criteria.

Evidence on effectiveness

Clinical data show clear differences between Wegovy and other medicines. NHS England notes that, when combined with lifestyle support, semaglutide can lead to average losses of 10–15% of body weight over a year. By contrast, trials of orlistat suggest typical losses of around 5–7% of body weight, with some people losing less. Combination tablets such as naltrexone/bupropion, which act on appetite and reward pathways, tend to fall in a middle range, though they are not routinely commissioned in the NHS. These figures highlight why GLP-1-based therapies like Wegovy are regarded as the most effective of the currently available treatments.

Considering side effects and tolerability

Effectiveness alone does not make one medicine the best choice for everyone. Orlistat, for example, can cause gastrointestinal side effects related to undigested fat, which some people find difficult to manage long term. Wegovy is better tolerated by many, but still causes nausea, diarrhoea, or constipation in the early stages for some users. Side effects from naltrexone/bupropion can include headache, insomnia, or raised blood pressure. NICE stresses that clinical suitability, risk factors, and individual tolerance should guide decisions about which medicine is most appropriate, rather than focusing only on potential weight loss.

Differences in convenience

How a medicine is taken also matters. Wegovy is a once-weekly injection, which some people prefer because it avoids the need for daily tablets. Others find injections less convenient or more daunting. Orlistat requires three doses a day with meals, making it more demanding in terms of adherence. Naltrexone/bupropion involves twice-daily tablets. For many, convenience and personal preference influence how well they can stick with a treatment, and this has a direct effect on outcomes. NHS clinicians therefore weigh practical considerations alongside clinical evidence when advising on the best option.

Variations across the UK

Access is not identical across the UK. In England, NICE guidance sets the eligibility framework for semaglutide, while NHS England commissions its delivery through specialist weight-management services. In Scotland, the Scottish Medicines Consortium (SMC) has its own assessment and sometimes applies slightly different criteria. Similarly, the All Wales Medicines Strategy Group (AWTTC) issues advice for use in Wales. This means that availability and eligibility can vary depending on where someone lives, even though the underlying evidence base is the same. Understanding these regional differences is important for anyone considering treatment.

The bigger picture

Comparisons make clear that Wegovy offers the most substantial average weight reductions among medicines currently available on the NHS, typically in the range of 10–15% of body weight over a year. Older medicines such as orlistat achieve smaller losses, usually closer to 5–7%, and often come with more restrictive side effects. Still, the “best” choice depends on each individual’s health, tolerance, and circumstances, as well as local commissioning rules in England, Scotland, and Wales. What emerges from the evidence is that Wegovy’s GLP-1 mechanism has set a new benchmark for effectiveness, but prescribing decisions remain rooted in clinical judgement and individual suitability.