Weight loss drug demand continues to grow in the UK – here’s what’s being done to keep supplies readily available

Source: ForeignAffairs4

Source: The Conversation – UK – By Liz Breen, Professor of Health Service Operations, School of Pharmacy & Medical Sciences, University of Bradford

Over a fifth of people in the UK have tried to access a weight loss drug in the last year, according to a recent poll.

Weight loss jabs such as Mounjaro (tirzepatide) and Wegovy (semaglutide) are very effective in managing obesity. Clinical trials have shown that some people lose up to 26% of their body weight while using these drugs.

With this impact, it’s no wonder a growing number of people are seeking out these products – often buying them in private clinics or online. But with plans to expand access to these drugs through NHS prescriptions, there are concerns that supply may not meet demand – especially for those people in most need.

In the UK, NHS prescriptions for weight loss jabs are only approved for people who meet strict eligibility requirements. For example, to qualify early for Mounjaro from your GP, you must have health problems due to your weight and a body mass index greater than 40 (adjusted for ethnicity). People assessed by the NHS and given prescriptions will also have access to additional support – such as advice about diet and physical activity.

Weight loss drugs can be prescribed by specialist clinics and, increasingly, local GPs. But a lack of time and resources means even those who are eligible are left waiting. Consequently, people who can afford to do so are approaching private providers for access to these medicines – despite the potential risks to their health.

There’s also evidence that people who aren’t clinically eligible for weight loss jabs prescribed by the NHS are purchasing them from online pharmacies.

Supply issues

Demand for weight loss jabs is about to grow, as the provision of Mounjaro via GPs is imminent, pending the creation of an infrastructure to support safe local prescribing.

The number of monthly GP prescriptions in England for Mounjaro has already risen from under 3,000 in March 2024 (on introduction) to over 200,000 in May 2025. Mounjaro (also marketed in the US as Zepbound) is widely considered to be the best weight loss jab currently available and a great commercial success.

GP prescriptions of all forms of semaglutide (the active ingredient in Wegovy) are more stable, at around 130,000 items per month (including generics and products to treat diabetes).

While a number of GLP-1 drugs faced shortages last year (including Wegovy and Mounjaro), these shortages have now been resolved. Shortages were spurred by a spike in global demand for these drugs alongside stockpiling by private clinics to feed requests.

Still, there were reports early this year that certain strengths of Mounjaro were difficult to access. The reasons for this are not clear, but may be due to the novelty of access to this new medication or a lack of access to alternatives.

Around 220,000 people in England are due to be offered Mounjaro via the NHS over the next three years. However, it’s estimated that 3.4 million people in England could actually be eligible for Mounjaro.

Wider NHS access to this drug is being phased to manage staff workload and ensure good support for patients. Phased rollout may also help to ensure there is enough supply for those who need to be prescribed one of these medications.

Future access

It’s likely that demand for these weight loss drugs will only continue to grow in the UK, so it’s important that supply is readily available.

Regulatory agencies have taken some steps to tighten controls of online prescribing of weight loss drugs and prevent misuse. Registered online pharmacies must seek independent verification of key clinical information (such as from a GP or through a person’s medical records) instead of relying on questionnaires or phone calls.

However, weight loss products remain easy to access for people with money and savvy search skills, but who may be clinically ineligible. The scale of demand from this group is difficult to quantify, but it’s clear more needs to be done to keep patients safe and manage demand.

Several new weight loss drugs are undergoing trials in the UK. These drugs will work similarly to those already available but may be administered differently (such as an oral tablet). The trials for these and subsequent approvals will not only increase market competition, but also improve patient access and choice.

Key patents for the manufacture of semaglutide are also due to expire in 2026 and 2031. Once a pharmaceutical product is outside of its patented time frame, other companies can be approved to manufacture it as a generic product.

A generic product is approved on the basis that it works in the same manner and has equal benefits to the original product. The generics market allows new entrants and new versions of these very popular products onto the market.

Generic products are usually less expensive and so are bought (where still clinically safe and effective) by the NHS. This change could provide greater access to weight loss medications and save the NHS and patients money in the long term.

Generic semaglutide products will probably be available in the UK from 2032 but will be initially authorised to treat diabetes rather than weight loss. Still, this should have a positive impact on the availability of prescription drugs used for both diabetes and weight management.

Generic liraglutide is already available on the NHS for the treatment of diabetes. The liraglutide brand Saxenda is also marketed for weight management. However, liraglutide is less effective than Wegovy or Mounjaro and requires daily injections.

The number of monthly NHS prescriptions for liraglutide has fallen from over 40,000 in July 2020 to 1,000 in May 2025. This fall was most likely influenced by the discontinuation of the Victoza brand for type 2 diabetes in late 2024. Shortages of all types of GLP-1 drugs, which lasted until the end of 2024, may also have impacted demand for liraglutide.

For now, NHS staff can report on known demand for these products to inform manufacturing quantities and procurement. What isn’t known is the future demand for online or private purchases of weight management drugs. It’s this “unknown” demand that may mean supply security is challenged and unsustainable.

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The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.

– ref. Weight loss drug demand continues to grow in the UK – here’s what’s being done to keep supplies readily available – https://theconversation.com/weight-loss-drug-demand-continues-to-grow-in-the-uk-heres-whats-being-done-to-keep-supplies-readily-available-262065