Everyone is talking about GLP-1 medications. To some they're a miracle cure for obesity. For others they're a dangerous fad. So, what's the reality?

First, the good news. Three new Cochrane reviews commissioned by the World Health Organization confirm that GLP-1 receptor agonists deliver clinically meaningful weight loss compared to placebo:

• tirzepatide arguably achieved the strongest results, reducing body weight by about 16% over 12–18 months, with effects sustained up to 3.5 years in some trials.
• semaglutide led to an 11% reduction over 24–68 weeks, supported by 18 trials involving nearly 28,000 participants. It increased the likelihood of achieving at least 5% weight loss but was linked to mild-to-moderate gastrointestinal side effects.
• liraglutide (daily injection) produced a more modest 4–5% reduction, though still meaningful compared to placebo. 

On the negative side, these reviews found GLP-1 drugs showed little difference from placebo in major cardiovascular outcomes, quality of life, or mortality. There were also side effects, particularly in the form of nausea and digestive issues.

Flying under the radar

Research into the potential of GLP-1 medications is hindered by the fact they are largely used outside NHS treatment pathways. Online vendors are currently providing the drugs directly to thousands of patients, often with no requirement that their GP is informed. This means information on their impact often doesn't make it as far as medical records.

As a result, we still know little about the real-world use and impact of GLP-1 medications. This includes patients' experience of using the drugs. 

A recent study by Thompson et al (2025) attempted to find out more. The results revealed real-world weight loss with GLP-1 medication is generally lower than RCT results, mainly due to poor adherence and suboptimal dosing. The study also reported high discontinuation rates, with 20–50% stopping treatment within the first year.  

On the positive side, highly adherent patients were found to achieve outcomes similar to trials (up to 14% with semaglutide and 18% with tirzepatide). In addition, no strong real-world evidence of severe risks (eg pancreatitis, thyroid cancer) were found, although rare outcomes like eye disease do need further study.

Rebound effect

A common concern relating to the use of GLP-1 drugs is that weight loss often doesn't persist long after discontinuation. Reiss et al (2025) discuss how this may be prevented.  For instance, educating patients on mindful eating practices and ensuring sufficient protein intake may support sustained weight loss and promote overall health. The authors also point to the potential benefit of engaging people in regular physical exercise, which itself can be enhanced by referring people to activities that have a strong social element to them (McNally, 2025).

While a lot of options are there, at this time it's safe to say we need more research on preserving the weight loss achieved with GLP-1 medication. As Reiss et al point out: ‘Studies are clearly needed to find ways to support withdrawal of pharmacotherapy without weight rebound using a multi-disciplinary approach which would likely involve behavioural change, nutritional guidance, structured physical activity and perhaps peer support groups.'

Babies out with the bath water?

So, it's clear that there are issues with GLP-1 medications. These include the potential side effects, weight regain after discontinuation, and of course, the eye-watering cost of providing them on the NHS. But should this lead to us rejecting them outright as useful option within treatment?

Certainly not. Despite the concerns discussed here, there's no doubt these medications are groundbreaking. 

They have the potential to seriously enhance our ability to tackle the rising tide of obesity, along with the significant healthcare costs attributable to it.  An area where we've had precious little success to date. 

And let's face it, even if we turn our back on GLP-1 medications as an NHS treatment, thousands of people will continue to use them. What is more, the costs of paying for the medications privately will only serve to drive health inequalities upwards.

So, rather than throwing the baby out with the bathwater, maybe we can work to harness the clear effectiveness of GLP-1 medications for weight loss while working to mitigate the negative effects inherent in their use. 

Clinicians and commissioners alike should keep an open mind to ways in which we can incorporate this innovation into patient care. Multi-agency treatment pathways, collaboration with public health programmes and data-led targeting of the patients most likely to benefit all have potential.  

In the meantime, let's not forget what causes obesity in the first place. We continue to be surrounded by ultra-processed, calorie dense food which is marketed aggressively to us (and our children) every time we turn on the TV, look at our phone or walk down the street. 

GLP-1 meds might curb your appetite, but they can't outsmart a world where crisps are sold in packs the size of bin bags.