A mass rollout of weight loss injections begins across the NHS on Monday, with GPs able to prescribe Mounjaro for the first time.
The drug, also known as tirzepatide and manufactured by Lilly, is an antidiabetic medication that works by lowering blood sugar levels and slowing down the digestion of food.
From Monday, GPs will be able to offer Mounjaro to severely obese individuals who also suffer from a range of other health complications.
Under the previous system, patients could only access such treatments through specialised weight loss services.
This major initiative is expected to reach approximately 220,000 people across England over the next three years, targeting those identified as having the "greatest need" for intervention.
But leading family doctors said some GPs have expressed concern about the additional workload linked to the rollout.
And pharmacy experts also said there could be pressure on supplies of the drug.
Who can get prescribed Mounjaro on the NHS?
In the first year of the programme, the drug will be offered to people with a body mass index (BMI) score of over 40 who have at least four other health problems linked to obesity, such as type 2 diabetes; high blood pressure; heart disease; and obstructive sleep apnoea.
Estimates suggest around 1.5 million people in the UK are already taking weight loss drugs, which may have been prescribed through specialist weight loss services or via private prescription.
Professor Kamila Hawthorne, chairwoman of the Royal College of GPs, said: “While we recognise the potential benefits of weight loss drugs, we know many GPs are concerned about the implications of the rollout of weight loss drugs into general practice, both in terms of workload and training to appropriately initiate and manage these treatments.
“The college shares these concerns, which is why we were pleased NHS England suggested a phased roll-out of Mounjaro as a treatment for weight loss. As and when this is escalated, appropriate resourcing for general practice – including access to ‘wraparound’ services – and training for GPs must follow.
She added: “GPs and our teams are already working under intense workload and workforce pressures, and this must be factored into this rollout in order to guarantee it can be delivered safely.
“More widely, whilst weight loss medications have a lot of potential benefits for patients who are struggling to lose weight and who meet all the clinical criteria for a prescription, they mustn’t be seen as a ‘silver bullet’ to aid weight loss.
“We also need to see a focus on prevention, stopping people becoming overweight in the first place so they don’t require a medical intervention later.”
Dr Hawthorne said there is no “one size fits all approach” and that the rollout of the jabs should not “come at the expense of other weight loss service”.
She continued: “The roll-out of weight loss medications in the NHS will need to be consistently evaluated to ensure that there is evidence that these prescriptions are of long-term benefit to patients.”
Olivier Picard, chairman of the National Pharmacy Association, said: “The demand for weight loss jabs continues to rise sharply, and more GPs have been directing patients back to pharmacies after initial inquiries, to access these treatments privately.
How do weight-loss jabs work?
Explained
Weight-loss injections, also known as GLP-1 receptor agonists, work by mimicking the natural hormone which regulates blood sugar, appetite and digestion.
They can be prescribed to lower blood sugar in people living with type 2 diabetes, but can also help people to lose weight.
Diabetes UK explains that the drugs increase the levels of a type of hormone called incretins, which help the body to produce more insulin when needed and lower blood sugar levels.
The drugs also reduce food cravings and slow down how quickly food is digested.
This can reduce the rate glucose is absorbed into the bloodstream. As a result, it makes those who take it feel fuller for longer, eat less and lose weight.
“As the NHS is now moving to implement National Institute for Health and Care Excellence (Nice) guidance, and tirzepatide becomes prescribable to more patients, we expect to see prescription volumes increase rapidly.
“However, NHS provision won’t meet demand straight away, so we fully expect that many people will continue seeking it privately from a pharmacy.
“Pharmacists are experts in medication and many of us have lots of experience delivering weight loss injections as part of a package of care including lifestyle advice.
“We are well placed to help roll out weight loss treatment on the NHS, with the right funding to support it.
“The biggest concern we have is that prescribing these medications alone misses the point.
“They should be part of a comprehensive weight management strategy – combining lifestyle coaching, exercise, and nutritional guidance. In reality, many GPs lack the bandwidth to deliver the level of support needed to ensure proper understanding and follow-up.
“As a result, we could end up in a situation where patients are prescribed the medication, lose weight, and then experience rebound weight gain once the course ends – simply because the foundational lifestyle changes weren’t addressed.”
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