KPV

The last three amino acids of α-MSH, a natural 13-amino-acid hormone that calms inflammation. Much of α-MSH's anti-inflammatory activity has been traced to this tail.

Unlike full α-MSH, KPV seems to work largely without the classic melanocortin receptors. It enters cells through PepT1, a small-peptide transporter that is switched on in the inflamed colon, and blocks NF-κB and MAP-kinase inflammatory signaling, lowering cytokine release.

In mouse colitis models, KPV given in drinking water reduced inflammation and inflammatory cytokines, with uptake depending on PepT1. It sped recovery in two colitis models and rescued mice lacking the MC1R receptor from colitis-related death. In a colitis-associated cancer model it prevented tumor formation, though the same study found high PepT1 levels increased tumors. Gut-targeted nanoparticles matched free KPV's effects at far lower concentrations. No human pharmacokinetic or safety data exist, and whether other routes reach the gut cells studied is unknown.

Human side effects are unknown because no human exposure data exist. FDA earlier listed it as a significant safety concern for that reason, and FDA's scientific reviewers recommended against compounding in 2026, citing thin safety and characterization data. PepT1's role in promoting tumors in mice makes long-term effects uncertain.

Not approved for any use. FDA removed it from Category 2 in April 2026 without moving it to Category 1. In July 2026 FDA's Pharmacy Compounding Advisory Committee voted 8–6–1 to recommend adding it to the 503A bulks list; the vote is advisory, FDA had issued no final rule as of October 2026, and it concerns pharmacy compounding for patients, not research-grade material. Not named on the WADA list but likely falls under S0. Status as of October 2026.