My husband was asking why insulin can’t be ingested orally, and I said it’s because it’s a rather large protein.
But then I remembered there is another rather large protein that can be absorbed from food, and is part of why gluten causes problems for people, because it opens pores in the intestines to receive large proteins (do these pores let in other stuff? )
Gliadin and SOD together can form a complex Glisodin.
Gliadin looks like a pretty big capsule. Could it be exploited to deliver insulin? Hard to know. This is the first time I’ve checked the scales involved.