Peptides are protein-based drugs, like insulin. With a few exceptions, they're not orally bioavailable -- your stomach breaks apart the amino acid chains and r

Peptides are protein-based drugs, like insulin. With a few exceptions, they're not orally bioavailable -- your stomach breaks apart the amino acid chains and reduces them to their smaller component parts. The ones mentioned in the article are either agents that assist with soft tissue recovery from exercise, or spur the body to release growth hormone and IGF-1. (i.e. are "growth hormone secretagogues.") You could inject growth hormone directly -- which is a very large peptide -- but it's much more expensive and can also be much harder to get, on account of the fact that it's more tightly regulated and controlled.