Britain counts packs and money, so the people had to be counted by telephone
- Cross-sectional household survey carried inside the Smoking and Alcohol Toolkit Study, a monthly telephone survey of adults in Great Britain that recruits about 2,450 new respondents a month by a hybrid of random probability and quota sampling and weights them by raking to the UK Census and Office for National Statistics profile. Between January and March 2025 the additional items on GLP-1 medication went to all participants aged 18 and over in England and to roughly half of those in Wales and Scotland; 5,893 adults answered. Sarah Jackson and colleagues, University College London. Open access in BMC Medicine, volume 24, article 1, published 8 January 2026, DOI 10.1186/s12916-025-04528-7.
- What counted as use was a brand name spoken on the telephone. Respondents said whether in the past twelve months they had taken medication for type 2 diabetes, to lower the risk of heart disease, or to support weight loss and reduce food cravings, and then which of five products they had taken: Saxenda (liraglutide), Ozempic (semaglutide), Wegovy (semaglutide), Mounjaro (tirzepatide), Rybelsus (semaglutide). 4.5% had taken one of the five for any reason. 2.9% [2.4–3.4%] had taken one to support weight loss, which scales to about 1.6 million adults, and 1.7% [1.4–2.1%] for weight loss alone, about 910,000. Mounjaro was the most used product, 2.3% of the whole sample.
- Among the 96.0% [95.5–96.6%] who had taken nothing for weight loss in the past year, 6.5% [5.7–7.3%] said they would be likely to consider a weight-loss medication in the next twelve months, about 3.3 million adults, and 2.5% [2.1–3.0%] said very likely, about 1.3 million. Users and interested non-users together come to roughly 4.9 million, close to one adult in ten.
- 85.0% [79.3–90.7%] of past-year users for weight loss named a product licensed for weight loss in Great Britain, which leaves 15.0% who named one that is not; among those using for weight loss alone the licensed share was 91.4% [85.6–97.2%]. Use showed no overall gradient by social grade or financial situation, but interest did: 11.7% among respondents finding it very difficult to manage financially against 4.5% among those living comfortably (OR = 2.01 [1.16–3.48]), and 13.4% among those out of paid work through long-term illness or disability against 6.7% of everyone else (OR = 1.85 [1.19–2.88]).
The scene is ordinary by now. A patient comes in to review an antidepressant and mentions, near the end of the appointment, that she has been on Mounjaro since the autumn. It did not come from her general practitioner: a form on a pharmacy website, a photograph uploaded, a pen by courier every four weeks. Her GP record does not hold it, and no national register holds her. Britain can say how many pens were dispensed and what they cost. How many people are injecting them, and who those people are, is a different question, and answering it took a telephone.
Five brand names on a telephone line
Sarah Jackson and colleagues at University College London put the question into the Smoking and Alcohol Toolkit Study, a monthly survey that recruits about 2,450 adults and weights them to the population profile of England, Scotland and Wales. From January to March 2025 the extra items reached 5,893 people. They were asked what they had taken in the past year and for what, then handed five brand names to choose from.
2.9% [2.4–3.4%] named one of the five for weight loss, 1.7% [1.4–2.1%] for weight loss and nothing else. Against 53.7 million adults that is about 1.6 million people, of whom roughly 910,000 take these drugs for weight alone. Mounjaro carries the market: 2.3% of the whole sample took it for any reason, and for weight loss specifically it stands at 2.0% against 0.6% for Wegovy, the next product down.
Of everyone using a GLP-1 for weight loss, 85.0% [79.3–90.7%] named a product licensed for that purpose in Great Britain. The remaining 15.0% named one that is not, which means Ozempic or Rybelsus, both licensed here for type 2 diabetes.
Set the headline number against the plans written for it. NHS England expected to treat 220,000 people in the first three years. NICE puts the eligible population at 3.4 million. The measured 1.6 million sits between the two, and most of it never passed through an NHS clinic.
Where the wanting sits
Among the 96.0% who had taken nothing for weight loss, 6.5% [5.7–7.3%] would be likely to consider it within a year and 2.5% [2.1–3.0%] said very likely. About 3.3 million adults, 1.3 million of them at the near end. Add the current users and something close to one adult in ten is either on these drugs or moving towards them.
Use is spread fairly evenly across social grades. Interest is not. 11.7% of respondents who described themselves as finding it very difficult to manage financially would consider a weight-loss drug, against 4.5% of those living comfortably. Among people out of paid work through long-term illness or disability the figure is 13.4%, against 6.7% of everyone else. A private course runs at around £200 a month, so the demand is heaviest where the money is thinnest.
Two more figures belong to the psychiatric clinic. Moderate or severe psychological distress in the past month, K6 of 5 or above, went with both use (3.7% against 2.4%; OR = 1.62 [1.13–2.32]) and interest (10.0% against 5.2%; OR = 1.81 [1.40–2.35]). Respondents reporting a past eating-disorder diagnosis reported more use (4.4% against 2.1%) and more interest (13.2% against 7.3%), although that item ran in one wave only, 4.2% reported a diagnosis, and both intervals are wide.
For the clinician the practical residue is small and firm. A medication list is now incomplete unless the drug is asked for by brand, because roughly one adult in thirty-four has taken one of these five in the past year, the share rises among patients in distress, and a courier delivery leaves no trace in the record a psychiatrist or psychologist is likely to see.
Britain can count the pens it dispenses and the money they cost, and it took a telephone survey of 5,893 households to establish that about 1.6 million adults have used these drugs for weight loss and another 3.3 million would consider it. 15.0% of users named a product not licensed for weight loss, and interest runs at 11.7% among people finding it very difficult to manage financially against 4.5% among those living comfortably.
Height and weight were not collected, so these data cannot say whether any user met the licensed criteria, a body mass index of 30 and over or 27 and over with a weight-related condition, or the tighter thresholds NICE sets for the NHS; the authors state plainly that the appropriateness of use against medical criteria cannot be assessed here. The paper nonetheless reaches a conclusion about where the drugs come from. It places its 1.6 million beside an estimate from the life-sciences analytics company IQVIA of about 1.4 million people in the UK accessing GLP-1 medications privately each month, mostly through online pharmacies, and reads the closeness of the two figures as support for the view that most GLP-1 use for weight loss in Britain is private rather than NHS provision. Supply was not measured in the survey: participants were never asked where or how they obtained the drug, because funding for the GLP-1 items was limited. That conclusion therefore rests on a commercial market estimate set beside a self-report figure. All answers were self-reported over twelve months of recall, and the design is cross-sectional, so the associations with distress and with eating-disorder history carry no direction. The eating-disorder item was carried in one of the three monthly waves and only 4.2% reported a diagnosis, which is why its intervals are wide (OR = 2.12 [0.69–6.53] for use, OR = 1.59 [0.66–3.82] for interest). Five products were named and anything else fell into a general option, so compounded and illicitly sourced material has no separate count. The survey is of Great Britain and excludes Northern Ireland.