I keep seeing KPV and BPC-157 mentioned in the same breath for anything gut-related, but they're pretty different molecules with different (and differently-sized) evidence bases, so I wanted to lay out what I understand and invite corrections.
KPV is a tripeptide fragment of alpha-MSH. Most of what exists is preclinical — cell and rodent models of colitis showing reduced inflammatory signaling, some interest in it as an anti-inflammatory that acts at the epithelial level. BPC-157 is a synthetic peptide studied mostly in rat models for a wide range of tissue-healing endpoints, including GI tract injury. The rat data looks striking, but human data is essentially absent and a lot of the literature comes from a small cluster of research groups.
My honest read: both are interesting mechanistically, neither has the human evidence people often assume, and the confident claims you see online outrun the science by a wide margin. Curious whether others have found controlled human trials I've missed — I haven't been able to.