I will take the best estimate I can find and try to have the numbers represent the facts at the end of the year.
IMO "about as popular as SSRIs" is a good point to start from. Price will be influential: right now a lot of people think they are very expensive and don't take them as a result. The price could go up if regulatory crackdown or it could go down. I don't think we'll ever see all obese Americans take them due to conservatism (small c).
Interesting subsidiary question: what % GLP users will be obese at the start of the treatment? Many of the people I know who take them are actually normal weight or slightly overweight and want to slim down for aesthetic reasons
Similar to Sam's original comment, a decade ago we saw 10-15% of adults on antidepressants.
Even in 2023 we're looking at an average of 17% usage (by gender: 24% of women)
I would expect usage for GLP-1s to surge early, see some churn (injections, side effects) and then continue to grow slowly until something better comes along.
So: how likely is it that the something better is an easier to take GLP-1? How likely is it that it's something else entirely (eg something easy to discover with alphafold n)? If it's something else entirely, it would probably stop growth in usage of GLP-1s, but not cut them altogether unless there's a very bad long term side effect of GLP-1s (something I don't expect to see, ie <5% chance). Those tails seem equally likely, we're currently at 6% or something. It's notable that up to 12% have tried (that means half of all users stopped)
@wrhall If half of all users have stopped, that makes >50% exceedingly unlikely (would almost certainly need new glp 1 form factor), although given the duration of this market it isn't worth it for anybody to bet those down further
Is anyone trading this actually on GLP-1 drugs, or talking with someone who is?
@jBosc Does anyone take them less often than once a month? Regardless I would be inclined to count any kind of periodic prescribed dosage