Ignoring one of the pseudo-"peptide" or whatever the fuck kind of medication they were probably offering me, actual peptides do have various useful applications—though they weren't commonly referred to like that, take Insulin or even Creatine as an example.
For a brief description, Peptides are strings of molecules called amino acids and they are essentially the building blocks of protein.
I don't want to go deep in the rabbit hole with it but compared to other drugs, it had fewer side effects and since their byproducts of amino acids could be recycled by our bodies, it was much, much safer to take than the former.
But yeah, I've heard of different Peptides aiding in the recovery and strengthening of bones but not to the extent that allowed Jolene, a.k.a. The Senator or the Admiral's wife, to have the ability to reconstruct her skeletal system that fast, and slowly had them get stronger and stronger despite the rest of its body continuously decomposing.