The number you will see in every headline about TRIUMPH-1 is 28.3%. It is real, it is now in the New England Journal of Medicine, and it is not the most useful number in the paper.

28.3% is the efficacy estimand for retatrutide 12 mg. It estimates average weight loss at 80 weeks if participants had remained on their assigned study treatment, with the dose interruptions and reductions the protocol allowed, and without starting a prohibited weight-management treatment. The treatment-regimen estimand, 25.0%, counts everyone who was randomized, whatever happened next. Both are population averages, and they answer different questions. Neither is the number I kept coming back to, which sits in a quiet paragraph on page four: in the final week of treatment, only 54.0% of the 12 mg arm was receiving 12 mg.

So here is the myth that should die before retatrutide reaches a pharmacy shelf: that the goal of obesity pharmacotherapy is to push every patient to the highest dose they can tolerate. TRIUMPH-1 does not prove the alternative. It does make the question hard to ignore, and the authors raise it themselves.