The present invention relates to a compound for use in a method of treatment of the human or animal body by therapy, in which method (i) the human or animal body is treated by administering one or more therapeutic peptides, and (ii) said compound is administered to inhibit degradation of said one or more peptides by one or more gut proteases, wherein the compound is a bile acid or a biguanide, or a pharmaceutically acceptable salt of a bile acid or a biguanide, wherein said bile acid is chosen from chenodeoxycholic acid, ursodeoxycholic acid, glycochenodeoxycholic acid and glycodeoxycholic acid.
