The worst case is worse than that: in addition to composition of matter patents there are dosage patents that can be invoked.

https://www.fiercepharma.com/pharma/novo-nordisk-patent-sema...

I am not familiar with pharma patents. Are you saying, for example, a 300ml dose could have a patent with different expiry than a 400ml dose?

I could see patenting mechanism of delivery, like injections versus oral, but not the example above.

Pharma is notorious for changing the formulation just enough to acquire a new patent to restart the clock. I wouldn't be surprised if the dosage was a factor in the process.

That doesn’t mean the existing drug can’t be sold as a generic.

Sometimes it means exactly that: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4968089/

Of course you could still sell the same drug if you get it approved with a different dosage but that is a long and costly process.

That still presupposes a new patent with new dosage.

In this case, is there a dosage patent on ozempic’s current dosage? If manufacturers tweak ozempic’s current dose and get a patent, what’s to stop the existing dosage from being made by generics?

I really don't think you're being skeptical enough.

https://www.nbcnews.com/health/health-news/gaming-us-patent-...