While I am not endorsing insulin use in non-diabetics there are some bits of info to add:
Most important:
fortunately, insulin can be purchased from a pharmacy, without a prescription. Regular insulin (Humulin R, Novolin R)can be taken instead of rapid acting, just take it earlier.
And, NPH (Humulin N, Novolin N) can be used instead of long-acting.
Both are cheap. Why not get an FDA inspected product from a FDA inspected source?