Many people across the UK are living with obesity.
This can increase the risks of health conditions, including type 2 diabetes, coronary heart disease, stroke, and some types of cancer, such as breast or bowel.
Can weight loss drugs help patients achieve and maintain a healthier weight?
What are some common weight loss drugs and how do they work?
There are several medications licensed for weight management in the UK.
- Tirzepatide – sold as Mounjaro – a once-weekly, self-administered injection, which makes people feel fuller and less hungry.
- Orlistat – sold as Xenical or Alli – an older style medication, available as a capsule, which works by preventing around one third of the fat from food being absorbed.
- Liraglutide – sold as Saxenda – injected daily, and Semaglutide – sold as Wegovy (the UK equivalent of Ozempic) – injected weekly. Both reduce feelings of hunger while increasing fullness.
Are weight loss drugs available on the NHS and what’s the role of the private sector?
In November 2023, the Medicines and Healthcare products Regulatory Agency authorised the use of Tirzepatide (Mounjaro) as an option for weight loss and management in adults.
To access through the NHS, patients need to be under a specialist NHS Tier 3 weight management programme to be prescribed the drugs.
“Generally, this is managed in secondary care, where they will have access to a variety of health care professionals,” says Kim Ball, RCN Professional Lead in Primary Care. “For example, clinical psychologists, weight management advisers, specialist dietitians and doctors who specialise in obesity.”
Medication isn't the be-all and end-all
As a result, many patients not on these programmes have turned to the private sector, particularly online pharmacies, says Kim. “A lot of people are now purchasing the drugs privately and it’s a huge market,” she says. “But there are concerns because there’s variable practice in prescribing.”
In February 2025, the General Pharmaceutical Council (GPC) announced it was tightening the rules, with decisions no longer able to be based solely upon an online questionnaire.
Instead, key information, such as someone’s height, weight and body mass index (BMI), should be verified independently.
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Online prescribing should also include an appropriate two-way consultation, the GPC says.
In December 2024, guidance from the National Institute for Health and Care Excellence (NICE) recommended Tirzepatide as an option for weight management, saying it could now also be prescribed in primary care, providing people met the criteria.
However, the NHS says patients "will only be able to get Tirzepatide for weight management on the NHS if they have significant health risks related to their weight.”
What’s the criteria used to prescribe these drugs, and are they a standalone treatment?
Patients need to meet certain criteria before these medications are deemed a suitable option for treatment.
These include a BMI of usually around 35 or more, although this is reduced for certain groups.
They’re also likely to have at least one weight-related health problem, or have higher risks for issues such as cardiovascular disease.
It's vital you take a full patient history
All medicines for weight management should be used alongside a reduced-calorie diet and increased physical activity, says NICE.
Patients should be encouraged to increase their physical activity and improve their diet by choosing healthier dietary options regardless of any weight loss due to the other health benefits it can bring.
What are the risks and challenges of using weight loss drugs?
Weight loss medications are not a short-term quick fix, says Kim. “For Mounjaro, the recommendation is that patients must inject the medication once a week until they reach their desired weight,” she says. “It’s a commitment.”
Potentially they’re a drug for life. “If patients are not tackling the underlying cause of why they over-eat, once they stop the medication, there’s a risk they will revert to the same behaviours that have contributed to their weight increase ,” Kim adds.
There may also be side-effects. For the older style medication, Orlistat, this may include bowel leakage, defecating more frequently and with greater urgency, and flatulence.
Medication may only mask an underlying problem
Mounjaro may cause nausea, vomiting, indigestion, diarrhoea, constipation, stomach pain and fatigue.
“They’ll feel sick if they over-eat while on the medication,” Kim says.
There may be increased risks of pancreatitis – this is doubled although still occurs in less than 1% of patients – and thyroid tumours.
Evidence is currently deemed insufficient, but it’s an issue that’s under review and subject to further research.
“When you’re assessing a patient’s suitability for taking these medications, it’s vital you take a full history,” says Kim.
Patients must also take any medication correctly, alongside the right amount of nutrition, and strength training, or it may potentially lead to problems such as muscle wastage.“In some patient populations, such as older adults, that’s a real concern,” she says.
Are there alternatives?
People with severe obesity may be eligible for bariatric surgery on the NHS.
They will usually have a BMI of 40 or above, or 35 and above if they also have a serious health condition that could be improved with weight loss – for example, type 2 diabetes or high blood pressure.
“My advice to nursing staff is to signpost your patients to a range of different options to help weight loss,” says Kim. “Medication isn’t the be-all and end-all, and what works for one person, won’t necessarily suit another. It’s really important we don’t take a one-size-fits-all approach, just because this medication is available.”
What else can nurses do to support their patients?
Ensure your patients’ expectations of weight loss medications are realistic, says Kim. “There are lots of reasons why someone is overweight and unless you address those underlying causes you may not achieve long-term sustainable weight loss,” she says.
“Medication may only mask an underlying problem. There needs to be a holistic approach.”
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If a patient is keen to obtain the medication privately, make sure they do their research, Kim advises.
“They need to make sure it’s a reputable organisation,” she says. “There should be monitoring in place, and the drug must be safe and legal. We know there are counterfeits that have come onto the market, an issue which poses significant patient-safety concerns.”
