For laboratory research use only. KPV is not a drug, dietary supplement, or cosmetic ingredient supplied for human or veterinary use, and nothing below is a recommendation for administration to humans or animals.
KPV is the C-terminal tripeptide of alpha-melanocyte-stimulating hormone (α-MSH), corresponding to residues 11–13 of the parent thirteen-residue sequence. Interest in the fragment dates to late-1980s work reporting that the short tail retained measurable activity in inflammation assays in which the intact hormone was also active, despite lacking the internal message sequence responsible for melanocortin receptor binding. That dissociation — observed activity without the canonical receptor pharmacophore — is the central mechanistic question in the KPV literature, and it is why the fragment continues to appear in cell-culture and rodent studies of epithelial inflammatory signaling. This overview summarizes what the preclinical record describes, and where it stops.
Structure and chemistry
KPV is Lys-Pro-Val: a three-residue peptide with a free-base molecular weight of roughly 342 Da (C16H30N4O4), typically supplied as an acetate salt. It contains no cysteine and therefore no disulfide constraint, is freely water-soluble at neutral pH by virtue of the lysine side chain, and is conformationally restricted by the central proline — a combination that makes it comparatively robust to handle relative to larger, cyclized, or oxidation-sensitive peptides.
The structural point that matters most mechanistically is what KPV does not contain. Melanocortin receptor binding at MC1R through MC5R depends on the His-Phe-Arg-Trp core message sequence located at residues 6–9 of α-MSH. KPV lies entirely outside that motif. Consequently, most investigators do not treat KPV as a melanocortin receptor agonist, and studies that report activity for the tripeptide generally look for an intracellular or transport-dependent explanation rather than a cell-surface melanocortin event.
Mechanisms studied in preclinical research
NF-κB signaling in epithelial cell culture
The most frequently replicated in vitro observation involves the NF-κB pathway in human intestinal epithelial lines such as Caco2-BBE and HT-29 derivatives. In these systems, cultures exposed to KPV before stimulation with TNF-α or IL-1β have been reported to show less IκBα phosphorylation and degradation, diminished nuclear translocation of the p65 subunit, lower NF-κB reporter activity, and lower IL-8 secretion into the medium relative to vehicle-treated controls. Parallel reports describe attenuated MAP-kinase phosphorylation in the same models. These are relative, comparator-referenced measurements in immortalized cell lines, not demonstrations of a clinical effect.
PepT1-mediated uptake
A distinctive strand of this literature concerns how the peptide gets into the cell. PepT1 (SLC15A1) is a proton-coupled di- and tripeptide transporter, abundantly expressed in small-intestinal epithelium and reported to be upregulated in inflamed colonic epithelium, where it is normally scarce. Because KPV is a tripeptide, it is a plausible PepT1 substrate, and investigators have used that hypothesis as an experimental handle: competition with other di- and tripeptides, and transporter knockdown or overexpression, have been reported to shift the observed signaling readouts in the expected direction. Studies in PepT1-expressing models have described activity in the low-nanomolar range, orders of magnitude below the concentrations required in cells lacking the transporter — an internally consistent argument that the site of action is intracellular. Related work has examined nanoparticle-encapsulated delivery of the tripeptide in murine colitis models, which is a formulation question rather than a new mechanism.
Animal-model observations
KPV has been evaluated in chemically induced murine colitis models, principally dextran sulfate sodium (DSS) and TNBS. Investigators have reported differences in histological injury scoring, myeloperoxidase activity, and inflammatory cytokine transcript levels in treated groups compared with vehicle controls. Earlier work used acute irritant and hypersensitivity models in rodents. These studies are small, single-laboratory, heterogeneous in route and formulation, and inconsistently blinded; they are best read as supporting the cell-culture mechanism rather than as independent evidence of outcomes.
Antimicrobial observations in vitro
A separate line of work reported that α-MSH and its C-terminal fragment inhibited growth of Staphylococcus aureus and Candida albicans in culture. The proposed mechanism involves cyclic-AMP signaling within the microorganisms themselves rather than any host pathway, which makes this an essentially unrelated activity that happens to share a molecule. It is included here because it appears in reference lists and is often conflated with the epithelial signaling work.
KPV compared with related melanocortin sequences
KPV is frequently studied alongside its parent hormone and a synthetic derivative. They are not interchangeable in an assay, and the table below summarizes why.
| Property | α-MSH (1–13) | KPV (11–13) | KdPT (derivative) |
|---|---|---|---|
| Sequence | Thirteen residues, acetylated N-terminus | Lys-Pro-Val | Lys-D-Pro-Thr |
| Approx. molecular weight | ~1665 Da | ~342 Da (free base) | ~344 Da (free base) |
| Contains HFRW message core | Yes | No | No |
| Melanocortin receptor binding | Established across MC1R–MC5R | Not established; generally studied as receptor-independent | Not established |
| Pathway most studied | Receptor-coupled cAMP signaling; pigmentation research | NF-κB and MAPK signaling in epithelial cells; PepT1 transport | IL-1 receptor signaling |
| Typical research role | Reference agonist and comparator | Isolating receptor-independent activity of the C-terminal fragment | Probing an alternative signaling entry point |
The KPV product page lists the material specification and batch documentation for the tripeptide.
Laboratory handling and solution preparation
Lyophilized KPV is normally stored cold and desiccated, with reconstituted stock treated as short-lived and protected from repeated freeze-thaw cycling. The absence of cysteine removes the oxidation and disulfide-scrambling failure modes that dominate handling protocols for larger peptides, but the acetate counter-ion still contributes mass: molar calculations performed on the free-base weight will overstate concentration if the material is supplied as a salt, and the certificate of analysis is the place to confirm which form is in the vial.
Preparing a stock is ordinary laboratory arithmetic — peptide mass divided by diluent volume gives concentration, from which serial working dilutions follow. The reconstitution calculator performs this conversion. Because much of the published epithelial work spans nanomolar to low-micromolar exposures depending on transporter expression, accurate stock characterization matters more than usual when comparing results across models.
Limitations of the evidence base
Three constraints recur. First, the mechanistic core of this literature is intestinal epithelial cell culture plus chemically induced rodent colitis; nothing in that design supports extrapolation to other tissues, other species, or intact organisms outside those models. Second, no receptor has been identified for the tripeptide, so “mechanism” here means a set of observed pathway and expression changes with a transport-dependent uptake route, not a resolved signaling cascade. Third, human data are minimal, and the reports that exist are small and topical in scope. Batch identity and purity documentation for material used in research is published in the COA library.
Reviewed for research accuracy: July 30, 2026.
References
- Hiltz ME, Lipton JM. FASEB Journal. 1989;3(11):2282–2284. (Early report of activity for the COOH-terminal fragment of α-MSH in an inflammation model.)
- Cutuli M, Cristiani S, Lipton JM, Catania A. Journal of Leukocyte Biology. 2000;67(2):233–239. (In vitro microbial growth-inhibition observations for α-MSH and its C-terminal fragment.)
- Dalmasso G, Charrier-Hisamuddin L, Nguyen HTT, Yan Y, Sitaraman S, Merlin D. Gastroenterology. 2008;134(1):166–178. (PepT1-dependent uptake of the tripeptide in intestinal epithelial models.)
- Kannengiesser K, Maaser C, Heidemann J, et al. Inflammatory Bowel Diseases. 2008;14(3):324–331. (Melanocortin-derived tripeptides in murine colitis models.)
- Laroui H, Dalmasso G, Nguyen HTT, Yan Y, Sitaraman SV, Merlin D. Gastroenterology. 2010;138(3):843–853. (Nanoparticle-based delivery of the tripeptide in a rodent colitis model.)
- Brzoska T, Luger TA, Maaser C, Abels C, Böhm M. Endocrine Reviews. 2008;29(5):581–602. (Review of α-MSH and derived peptides, including the C-terminal tripeptide.)
- Luger TA, Brzoska T. Annals of the Rheumatic Diseases. 2007;66(Suppl 3):iii52–iii55. (Review of α-MSH-related peptides.)
- Studies of the KdPT derivative in murine colitis models and IL-1 receptor signaling are cited here generically; individual identifiers were not verified for this article.
Research use only. All compounds discussed are supplied strictly for in vitro laboratory and preclinical research by qualified personnel, and are not for human consumption, therapeutic use, cosmetic use, or veterinary application.