Weight-loss medications must be seen as treatments for a chronic condition and not simply as appetite suppressants, pharmacy leaders have said.
The advice comes as a study published in the BMJ on 7 January 2025 reported that people who used weight-loss medications regained weight faster compared with people who lost weight using behavioural weight management programmes only.
Researchers analysed 37 studies of weight-loss medication regimes undertaken by a total of 9,341 participants. The duration of the interventions varied (11–176 weeks), with an average of 39 weeks and an average follow-up of 32 weeks (4–104 weeks).
The studies included common weight-loss medications such as semaglutide, tirzepatide and liraglutide.
Generally, people using medication lost more weight than those who did not. The researchers observed that the average weight loss at the end of a course of weight-loss medication was 8.3kg compared with 5.1kg after behavioural weight management programmes.
The study data also showed that the average weight loss of participants when all types of medication were included was 5.7kg, which rose to 8.0kg with incretin mimetics (glucagon-like peptide-1 analogues) and 12.3kg with newer and more effective incretin mimetics (semaglutide and tirzepatide).
However, people who had used weight-loss medication tended to regain the weight more rapidly, with an average monthly weight regain of 0.4kg compared with 0.1kg in cohorts who had followed a behavioural weight management programme, the study revealed.
In addition, the researchers noted that the average monthly weight regain of participants was 0.3kg for all weight-loss mediations, which increased to 0.6kg for incretin mimetics and 0.8kg for newer and more effective incretin mimetics.
From the data, the authors projected that body weight after stopping weight-loss injections would return to baseline after 1.7 years, compared with 3.9 years after behavioural weight management programmes.
Kieran Seyan, chief medical officer at Lloyds Pharmacy Online Doctor, said: “Weight-loss drugs shouldn’t be seen simply as appetite suppressants that ‘reset’ weight and can then be stopped.
“They are treatments for a chronic condition, and for many patients, the benefits depend on appropriate duration, monitoring and follow-up.”
Seyan also referred to National Institute for Health and Care Excellence (NICE) guidance, published in August 2025, which said that people should be offered support for at least one year after their weight-loss medication or programme has ended, to reduce the risk of regaining weight.
“Recent data from NICE estimates that as many as four in five patients regain the weight after their treatment is discontinued, particularly where there is no structured transition or longer-term support in place,” he said.
“Without this, some patients may experiment with altering doses or stopping medication independently, which can lead to suboptimal outcomes.”
Olivier Picard, chair of the National Pharmacy Association, commented: “Although weight-loss treatment can help some people to achieve a healthy weight who may have struggled in the past by simply making lifestyle changes, patients should understand it is not a silver bullet. As this study shows, without sustained lifestyle changes, weight loss and the subsequent health benefits will not be sustained.
“It’s really important patients who are using this treatment are given full wraparound support by their pharmacy to make the long-term changes to diet and exercise they need to maintain a healthy weight.”
John Wilding, professor of medicine in the Department of Cardiovascular and Metabolic Medicine at the University of Liverpool, said: “The results are not surprising. Obesity is a chronic disease that usually relapses when treatment is stopped.”
However, Wilding added that he was hesitant to over-interpret the findings comparing weight-loss injections with behavioural weight management programmes.
“I would be cautious about interpretation of this as the populations included in these trials are likely to be different from those included in trials of medication, and I would always advocate lifestyle support to be used alongside weight-loss medications to optimise outcomes anyway,” he said.
The study authors also said: “We found no evidence that the intensity of behavioural support provided during treatment with weight management medicines impacted the rate of weight regain after treatment.”
Tricia Tan, professor of metabolic medicine, diabetes and endocrinology at Imperial College London/Imperial College Healthcare NHS Trust, said: “There is increasing evidence that structured exercise is important to prevent weight regain after cessation of weight-loss drugs, and this study does not discuss this as a strategy to reduce this problem.”
“Behavioural weight management programmes do not in the first instance seem to cause enough weight loss to materially improve cardiovascular disease, whereas we do have evidence from weight-loss medication treatment that these do improve cardiovascular disease,” she added.
“Fundamentally, weight-loss medications have been assessed as clinically effective in improving the health of people living with obesity and are cost effective.”
The NHS offers a 12-week digital weight management programme to adults living with obesity, who also have a diagnosis of diabetes, hypertension or both. The programme consists of behavioural and lifestyle advice tailored to the patient.
Tirzepatide (Mounjaro; Eli Lilly) may be offered on the NHS to patients with obesity who have other weight-related conditions, such as diabetes, hypertension and cardiovascular disease. Semaglutide (Wegovy; Novo Nordisk) may be offered on the NHS through a specialist weight management clinic if a patient has a body mass index in a certain range depending on ethnicity and weight-related health problems.
Currently, Wegovy can be prescribed on the NHS for a maximum of two years, while there is no limit on Mounjaro.