What the semaglutide trial actually showed

What they did

1,961 adults with obesity, or with overweight plus at least one weight-related condition, none of them diabetic, were randomly assigned two to one to a once-weekly 2.4 mg semaglutide injection or a placebo. Both groups got the same lifestyle program. It ran for 68 weeks, double-blind, across multiple countries.

What they found

Average weight change was −14.9% on semaglutide versus −2.4% on placebo. In kilograms, that was about 15.3 kg against 2.6 kg. Half of the semaglutide group lost 15% or more of their body weight; under 5% of the placebo group did. Cardiometabolic risk markers and self-reported physical functioning improved more on the drug.

The small print

Nausea and diarrhea were the most common side effects, usually mild to moderate and fading with time, but 4.5% of the semaglutide group stopped because of gut symptoms, versus 0.8% on placebo. The trial was funded by Novo Nordisk, the company that makes semaglutide. Neither fact cancels the result. Both belong in the picture.

The Luxe read

This is the study behind the headlines, and it is a strong one: large, randomized, blinded, and long. It answers one question well, whether the approved drug at the approved dose helps people with obesity lose weight over about a year. It does not answer what happens after you stop, whether a compounded version behaves the same, or whether it does anything for someone without a weight-related diagnosis.

Questions worth asking

• Do I match the people in this trial, or am I reading a result meant for someone else?
• What is the plan for muscle, protein and training while losing weight this quickly?
• What happens at week 69? Ask your prescriber before you start, not after.