KPV is the tripeptide lysine-proline-valine, the last three residues at the C-terminus of alpha-melanocyte-stimulating hormone, and it is studied as a small anti-inflammatory sequence that appears to retain the immunomodulatory character of the parent hormone without its pigmentation signalling. At 342.43 g/mol it is one of the smallest molecules in the research-peptide catalogue, and that size shapes everything about how it is handled: high molar yield per milligram, easy aqueous solubility, and a literature that is dominated by cell culture and rodent models of intestinal and cutaneous inflammation.
This page covers what KPV is, where the sequence comes from, the mechanisms reported for it, the research areas where it appears, and the practical laboratory matters — vial sizes, reconstitution arithmetic, storage and certificate interpretation. KPV is supplied here as a lyophilized powder for laboratory research only; it is not a drug, a supplement or a therapy, and nothing below is a protocol for use in humans or animals outside a controlled research setting.
KPV at a glance
| Property | Value |
|---|---|
| Sequence | Lys-Pro-Val (KPV) |
| Length | 3 residues |
| Parent molecule | alpha-MSH, residues 11–13 |
| CAS number | 67727-97-3 |
| Molecular formula | C16H30N4O4 |
| Molecular weight | 342.43 g/mol |
| Class | Melanocortin-derived anti-inflammatory fragment |
| Reported targets | NF-kappa B signalling; PepT1 transporter in epithelial models |
| Physical form | White lyophilized powder, sealed glass vial |
| Sizes supplied | 5 mg, 10 mg (injectable vials); oral capsule format also stocked |
| Purity specification | ≥99% by RP-HPLC with mass confirmation |
Origin and structure: a three-residue fragment of alpha-MSH
Alpha-melanocyte-stimulating hormone is a 13-residue product of proopiomelanocortin processing, best known for pigmentation signalling through the melanocortin receptor family. From the 1990s onward, work on the hormone separated two properties that had previously been discussed together: receptor-mediated pigmentary signalling, largely a function of the central His-Phe-Arg-Trp core, and anti-inflammatory activity, which several groups localised to the C-terminal tail.
KPV is that tail. Because it lacks the message sequence required for high-affinity binding at MC1R and MC4R, it is generally described in the literature as acting largely independently of classical melanocortin receptor signalling — which is the reason it became interesting as a research tool rather than a curiosity. A tripeptide of this kind is trivially cheap to synthesise by solid-phase peptide synthesis, chemically stable, freely water-soluble, and free of the disulfide bridges, oxidation-prone methionines and deamidation-prone asparagines that complicate longer sequences.
One structural consequence deserves emphasis for anyone planning molar calculations. At 342.43 g/mol, KPV is roughly one-quarter the mass of BPC-157 and about one-thirteenth the mass of LL-37. A 5 mg vial therefore contains approximately 14.6 micromoles of peptide — far more molar material than a 5 mg vial of almost anything else on the shelf. Comparisons run on a mass basis rather than a molar basis will systematically misrepresent KPV.
How KPV is thought to work
The mechanism most consistently reported is interference with nuclear factor kappa B signalling. In cultured cells, published work has described KPV reducing the nuclear translocation of NF-kappa B subunits and lowering the transcription of downstream pro-inflammatory mediators including interleukin-6, interleukin-8 and tumour necrosis factor alpha. This is an intracellular observation, not a receptor-binding one, and it raises the obvious question of how a hydrophilic tripeptide reaches the cytoplasm.
The answer proposed in the intestinal literature is the peptide transporter PepT1. Several groups have reported that KPV is taken up by colonic epithelial cells through this di- and tripeptide transporter, which is expressed at low levels in healthy colon and upregulated in inflamed tissue. If that account holds, it produces an elegant selectivity argument: uptake would be greatest exactly where the transporter is most abundant. It is worth treating this as a reported mechanism rather than a settled one; transporter-mediated uptake has been shown in specific cell lines and model systems, and the extent to which it generalises is not established.
A third strand concerns direct antimicrobial and antifungal observations. Alpha-MSH and its C-terminal fragments have been reported to reduce the viability of certain bacteria and yeasts in vitro at high concentrations, an activity that is mechanistically distinct from the NF-kappa B work and appears in a much smaller body of literature.
What research has examined
Intestinal inflammation models (rodent, in vitro)
The largest cluster of published KPV work sits in experimental colitis. Rodent studies using chemically induced colitis models have reported reductions in histological damage scores, myeloperoxidase activity and pro-inflammatory cytokine expression in animals given the peptide, with several papers focusing on oral and nanoparticle-based delivery to the colon rather than systemic exposure. Parallel in vitro work uses intestinal epithelial monolayers to read barrier integrity and cytokine output. These are preclinical findings; no human trial data support KPV for any indication.
Epithelial barrier and mucosal repair
Because barrier function and inflammation are coupled, KPV also appears in work on tight-junction protein expression and transepithelial electrical resistance in monolayer culture. Researchers comparing barrier-directed mechanisms often set it alongside larazotide acetate, which targets the zonulin pathway directly rather than through cytokine signalling — a useful contrast because the two act at different points in the same physiology.
Skin and wound models
A smaller literature examines KPV in cutaneous inflammation and wound-repair models, reflecting the origin of alpha-MSH research in skin biology. Here it is frequently studied alongside GHK-Cu, which is investigated through matrix remodelling rather than cytokine suppression.
Blend and combination research
KPV is a component of several multi-peptide research preparations, including the KLOW blend and BPC-157 + KPV. Whether combinations produce effects beyond their components has not been resolved in published work; our blends versus single vials guide covers the interpretive problems that arise when a certificate reports a mixture.
Forms and sizes we supply
The injectable-vial format of KPV is stocked in 5 mg (USD 50) and 10 mg (USD 75) lyophilized vials. Because of the low molecular weight, these sizes cover a large number of plate-based experiments; laboratories running molar-equivalent comparisons against larger peptides routinely find that a 5 mg KPV vial outlasts a 10 mg vial of a 3 kDa peptide.
Two oral formats exist for work that requires a gastrointestinal presentation: KPV capsules and BPC-157 + KPV capsules. The whole catalogue of related material sits under anti-inflammatory peptides, with the gut-directed subset under gut health peptides.
Reconstitution and storage in a laboratory context
Reconstitution is an arithmetic exercise, not a protocol for administration. A 10 mg vial reconstituted with 2 mL of bacteriostatic water yields 5 mg/mL, equivalently 5,000 mcg/mL; drawing 0.1 mL (10 units on a U-100 syringe) removes 500 mcg. Expressed in molar terms, 5 mg/mL of a 342.43 g/mol peptide is approximately 14.6 mM — a figure worth calculating explicitly before preparing culture dilutions, because working concentrations in the published cell literature are typically in the micromolar range and require substantial serial dilution.
KPV is highly water-soluble and does not need the pH adjustment or organic co-solvents that some hydrophobic sequences demand. Lyophilized vials are stored at −20 °C, protected from light and moisture; reconstituted material is refrigerated and aliquoted so that a single container is not repeatedly warmed and re-chilled. Full handling detail is in our peptide storage guide and the reconstitution guide, and the arithmetic can be checked with the reconstitution calculator.
Purity, COA and how to read one
Every lot is purified by reversed-phase HPLC to at least 99% and confirmed by mass spectrometry, with a certificate matched to the lot number printed on the vial. Three checks matter most for a tripeptide. First, confirm the observed mass is consistent with 342.43 g/mol for the free peptide — short sequences are the easiest to verify unambiguously by mass, so there is no excuse for an ambiguous spectrum. Second, read the HPLC trace rather than only the headline number: a single sharp peak with a clean baseline is what a well-purified tripeptide should look like. Third, check the counter-ion. Small peptides are frequently supplied as TFA salts, and residual trifluoroacetate has documented effects in cell culture; net peptide content differs from gross vial weight when salt and residual water are counted. Our COA reading guide and HPLC purity explainer work through real traces.
Regulatory status
KPV is not an approved drug in the United States or elsewhere and has no marketing authorisation for any indication. It is not a dietary supplement ingredient and is not a compounded medication in general availability. Material supplied here is research use only: for in-vitro and preclinical laboratory investigation by qualified researchers, not for human or veterinary administration. The distinction between research-grade material and an approved product is not a formality — it determines what claims can be made and what documentation exists.
Related peptides and further reading
Within the anti-inflammatory group, ARA-290 approaches inflammation through the innate repair receptor and VIP through VPAC receptor signalling — three different entry points into overlapping biology. For a direct structural and mechanistic contrast, see BPC-157 vs KPV. Broader context is in the gut health research overview and the healing and recovery overview, and the institutional catalogue groups related material under the melanocortin family and MSH family pages.