How many people are actually using GLP-1s?

How many people are using GLP-1s? It’s not an easy number to produce, even if you are one of the manufacturers holding the reins. Based on media reporting, it seems like a lot. But I haven’t seen anyone really dig into this mathematically, so I am going to try.

Let’s begin with one of the most oft-quoted figures on GLP-1 use. KFF[^1] produced a poll that found 12 percent of adults had tried a GLP-1. The BBC’s Science Focus quoted the 12 percent figure thus:

In the US, approximately 12 per cent of adults say they’ve tried GLP-1s – that’s 41 million people.

41 million—that’s a lot![^2]

But hold on. If we dig into the methodology of the KFF, the actual source of the 12 percent figure are from survey responses of 1,201 adults via the Internet. Polls are only ever approximations and can contain all sorts of biases—the inherent biases of people who answer polls on the Internet, just for one—especially when they are so small relative to the population people want to extrapolate them to. Even if it were a bigger, more comprehensive poll, it would never be good science-reporting practice to look at a poll of roughly a thousand people that found 12 percent of its respondents did something, multiply 0.12 by 340 million, and then state that, therefore, 41 million people have done it. (At best, it could be phrased like: “12 percent of respondents to a poll said they had tried at GLP-1; extrapolated to the U.S. population, that would be the equivalent of 41 million people.”)

Nonetheless—maybe the poll is right! GLP-1s are everywhere. People won’t shut up about them. Fully 50 percent of my TV and Reddit ads are for GLP-1s or their purveyors. After all, as one market report from Morgan Stanley effusively announced, GLP-1s were a 79 billion dollar business in 2025. (Morgan Stanley presumably has no opinion on public health either way, but it loves when people buy things.)

But how else could we put together some figures?