GLP 1 public health claims from Donna Ryan checked against the trial evidence

Donna Ryan, a veteran obesity researcher, used a press briefing in Korea to argue that GLP 1 drugs could matter for public health as much as statins or antibiotics. The GLP 1 public health case she made rests partly on firm trial data and partly on forecasts and opinion. This explainer separates the two, starting with the cardiovascular trial she helped to write up and ending with what remains unproven.

Who is making the argument

Ryan is professor emerita at the Pennington Biomedical Research Center of Louisiana State University and a former president of both the World Obesity Federation and The Obesity Society in the United States, according to Korea Biomedical Review. She spoke to reporters while attending the International Congress of Diabetes and Metabolism, a meeting run by the Korean Diabetes Association. Her central claim was that chronic diseases now call for a global public response of the kind once reserved for infections, and that drugs acting on the GLP 1 receptor, alone or together with the related GIP and glucagon receptors, can reach several of those diseases at once. She named diabetes, obesity, heart disease and liver disease as the main targets.

Readers should weigh such views alongside the speaker's ties. Ryan was a coauthor of the main paper from SELECT, a trial funded by Novo Nordisk, the maker of semaglutide. In the competing interest statement of a separate paper published in Nature Medicine this month, she listed consulting honoraria from many companies developing obesity drugs, including Novo Nordisk, Eli Lilly, Amgen, AstraZeneca, Boehringer Ingelheim, Pfizer, Regeneron and Zealand Pharma, as well as stock options in several smaller firms. Such ties are common among leading obesity researchers and do not make her arguments wrong. They are, however, relevant when an expert predicts a transformed future for a drug class with which she has professional and financial connections.

What the GLP 1 public health case rests on

The strongest evidence Ryan pointed to is the SELECT trial, published in the New England Journal of Medicine in November 2023. It enrolled 17,604 adults aged 45 or older with established cardiovascular disease, a body mass index of 27 or more and no diabetes, and randomly assigned them to weekly semaglutide injections or placebo. Over a mean follow up of 39.8 months, the combined rate of cardiovascular death, nonfatal heart attack or nonfatal stroke was 6.5% with semaglutide against 8.0% with placebo, a hazard ratio of 0.80. In other words the relative risk fell by about a fifth, and the absolute difference was 1.5 percentage points over roughly three years. The authors suggested weight loss and possible effects on inflammation and blood vessels may explain it.

In other words the relative risk fell by about a fifth, and the absolute difference was 1.5 percentage points over roughly three years.

SELECT also carried a cost that rarely features in optimistic forecasts. Adverse events led 16.6% of people on semaglutide to stop the drug for good, compared with 8.2% on placebo, according to the published trial abstract. The trial tested people who already had heart disease, so its result says nothing direct about people with obesity alone or about those without established disease. Ryan's wider claims, that the drugs also address liver disease and other chronic conditions, draw on other trials not described in her briefing, and the size of each benefit differs from one condition to the next. A single word such as transformative therefore hides very different levels of evidence depending on which disease is being discussed.

Forecasts and figures in the briefing

Some numbers from the briefing come from sources the report does not name, and they should be read as claims rather than findings. Ryan said an estimated 12% of Americans aged 12 and older currently use a GLP 1 drug, and the article cites industry forecasts that 29 new treatments acting on GLP 1, GIP or glucagon receptors could reach the market within three years. Neither figure is tied to a survey, registry or regulator in the report, and we could not trace them to a primary source. Ryan also said generic versions have appeared in countries including Canada and India and that new entrants should push prices down, which is a prediction about markets rather than a measured outcome.

Her caution about stopping treatment is better grounded. "When treatment stops, weight returns and health deteriorates, reversing the benefits gained from the medication," she told reporters. Withdrawal data from an extension of the STEP 1 semaglutide trial, and a 2026 BMJ meta analysis on stopping weight management medicines, have both examined weight regain, which means the public benefits she describes depend on people staying on treatment for years. She said long term data remain limited but that she finds the safety of these biologically based treatments reassuring, a judgement rather than a measurement. Readers comparing numbers across stories can use our figures page, where we log the trial results behind claims like these.

Access misuse and the limits of the GLP 1 public health argument

Ryan spent much of the briefing on access and misuse. She said demand in the United States far outstripped supply when the drugs first arrived, and that high prices helped drive the spread of compounded copies whose safety could not be assured. She also cited a Medicare bridge programme as a sign that the US government is trying to widen access, and said insurance data should help show how widely the drugs are used and whether they reduce costs to society. At the same time she warned against taking them purely to become thinner. "I do not think cosmetic weight loss is worth taking those risks," she said, adding that rapid weight loss can reduce muscle and bone mass.

The comparison with statins and antibiotics is Ryan's own, and it sets a high bar. GLP 1 drugs have strong trial evidence for weight loss and blood sugar control and, in SELECT, for fewer cardiovascular events in people with existing heart disease. What is still open is how they perform over decades at population scale, whether benefits last, who should stay on them for life and how health systems can pay for that. Those questions will be settled by long outcome studies and insurance records, not by expert forecasts. People considering treatment should get advice from a clinician who can weigh their own risks and should avoid unregulated copies. Our clinic section follows the trials behind these claims.

Conclusion

The GLP 1 public health argument from Donna Ryan mixes solid ground with forecasts. SELECT shows a 20% relative cut in major cardiovascular events for people with heart disease and overweight, at the price of more people stopping treatment for side effects. Usage figures, pipeline counts and price predictions in the briefing are claims to check, and a comparison with statins or antibiotics will need years of population data.

Source Briefing reported by Korea Biomedical Review, 22 October 2026. Trial: Lincoff AM and colleagues including Ryan DH. Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes. NEJM 2023. DOI 10.1056/NEJMoa2307563

Amino Weekly reports research. It is not medical advice and never gives doses.