KPV (Lys-Pro-Val): A Research Peptide Overview

KPV is a synthetic tripeptide with the sequence Lys-Pro-Val. It corresponds to residues 11 to 13 of alpha-melanocyte-stimulating hormone (α-MSH), the C-terminal end of that 13-residue melanocortin peptide. As the free peptide it carries CAS number 67727-97-3, the molecular formula C16H30N4O4, and a molecular weight of 342.44 g/mol. It is often supplied as an acetate salt, which adds the mass of the counter-ion.

As a research reference material it is supplied as a lyophilized powder and characterised by HPLC for purity and mass spectrometry for identity.

In the laboratory, KPV is used as a minimal model of the C-terminal region of α-MSH in melanocortin-pathway and NF-κB reporter assays in cell lines, where the research question is how much activity a three-residue fragment retains.

Because it is a tripeptide, it is also a substrate in studies of the PepT1 transporter, which carries di- and tripeptides across cell membranes, and it serves as an analytical reference standard. These are in vitro research applications only, and no medical claims are made here.

Lyophilized peptides are generally kept cold, dry, and out of light to preserve stability. KPV is stored long-term at -20°C (-4°F), protected from moisture and direct light, with original labeling retained so the batch stays traceable.

This overview does not cover preparation or use of any kind. That falls outside laboratory research reference use, and we do not provide that guidance.

A three-residue peptide leaves very little room for error, and very little room to hide one. A substituted residue or a truncated dipeptide such as Lys-Pro can elute close to KPV on a chromatogram, and a purity percentage alone cannot tell them apart. Mass spectrometry can: the protonated KPV ion sits at about m/z 343.2, and a fragment or substitution shows up at a different mass.

Small molecules also expose sloppy documentation quickly. A Lys-Pro-Val tripeptide contains exactly four nitrogen atoms, so a certificate that prints any other nitrogen count, or a molecular weight that does not follow from its own formula, deserves a second look. This is why a per-batch Certificate of Analysis, one tied to the exact lot you receive, is more useful than a generic brand-level document.

Before relying on any batch, confirm three things: purity (an HPLC percentage), identity (a mass-spectrometry confirmation at the expected mass), and a traceable lot number with a test date. If the supplier lets you look up that batch’s report, you can match the documentation to the vial in hand.

See our guide on how to read a peptide COA for a field-by-field walkthrough.

Is KPV FDA approved? No. KPV is not an approved drug in the United States. Its status for pharmacy compounding has been under FDA review during 2026, which concerns compounded clinical use and is separate from what is offered here: a laboratory reference standard supplied strictly for analytical and in vitro research. Nothing on this site is medical guidance.

Is KPV legal in the US? KPV is not a scheduled substance under the Controlled Substances Act. It is lawfully supplied as a reference material for laboratory research, and for no other purpose; nothing on this site should be read as a claim otherwise.

KPV versus alpha-MSH? α-MSH is the full 13-residue melanocortin peptide. KPV is only its last three residues, a different molecule with roughly a fifth of the mass, which is exactly the kind of difference mass-spectrometry identity testing exists to confirm.

Why a lyophilized vial and not another format? Reference material is quantified by mass and stability-characterised in lyophilized form, which is what a per-batch certificate can actually describe. Other formats fall outside laboratory reference use, so we do not offer them.