> and it is basically impossible to stop direct imports like that

How so? Is there a particular characteristic of the US that makes it so, or of the channels through which this is done? I get that in general it's impossible as with recreational drugs, but when you look at cocaine then at least to traffick it to most wealthy countries it takes a large amount of resources and is at high risk of getting caught. Which is why they're increasingly starting to use narco submarines. This greatly increases the price of the product. Why can't the same happen to peptide imports?