A Trace ‘Tides Primer: Understanding the lysine proline valine tripeptide

By: Laura Mildon

KPV is a tripeptide: a chain of three amino acids joined by peptide bonds. Its name uses the one-letter amino acid codes K for lysine, P for proline, and V for valine. Researchers study this short sequence to explore how peptide structure, cellular transport, and inflammatory signaling relate to one another.

KPV corresponds to the final three amino acids of alpha-melanocyte-stimulating hormone, usually called alpha-MSH. That structural relationship provides research context; it does not make KPV equivalent to the complete hormone or establish a benefit for a commercial research material.

Chemical identity

The formula and weight above describe the peptide without a salt counterion. The one-to-one acetate form has the combined formula C₁₈H₃₄N₄O₆ and a molecular weight of approximately 402.5 g/mol. These values should not be mixed when identifying a material.

PubChem record for the free-acid peptide

PubChem record for the acetate form

How KPV relates to alpha MSH

Alpha-MSH contains 13 amino acids. KPV corresponds to positions 11 through 13, at its carboxyl-terminal end. In peptide notation, this explains the related name alpha-MSH 11–13.

The terminal chemical group matters. Native alpha-MSH ends with an amide, while the free-acid KPV described above ends with a carboxyl group. A paper using an amidated fragment or another modified analogue should not automatically be treated as evidence about unmodified free-acid KPV.

Molecular structure

A molecular formula counts atoms; the sequence and chemical structure specify how they are connected. PubChem provides a two-dimensional depiction for the identified peptide. This is a chemical connectivity diagram, rather than proof of one fixed three-dimensional shape.

History and research origins

KPV research developed from studies of alpha-MSH and its shorter fragments. A 1984 study by Cody and colleagues examined the contribution of the Lys-Pro-Val terminal sequence in larger cyclic melanotropin analogues. That paper documents early structure–activity work, rather than a definitive discovery date for isolated KPV.

Cody and colleagues in Journal of Medicinal Chemistry 1984

Selected published research

KPV is not FDA-approved as a medicine. These selected studies describe experimental findings and their limits. They do not establish an intended application for a research product.

An alpha MSH terminal fragment in 1989

Hiltz and Lipton examined alpha-MSH 11–13 in a chemically induced ear-swelling model in mice. They reported reduced swelling under the experimental conditions, contributing to interest in the terminal sequence and inflammatory responses.

This was an animal experiment involving a specified hormone fragment. It does not establish clinical effectiveness, and the fragment’s terminal chemistry must be considered when comparing it with other KPV materials.

Hiltz and Lipton in The FASEB Journal 1989

Cellular transport and signaling in 2008

Dalmasso and colleagues studied KPV in intestinal epithelial and immune cell lines and in two mouse models of chemically induced colitis. They investigated PepT1, a membrane transporter that carries certain peptides containing two or three amino acids.

The researchers linked KPV uptake to PepT1 and reported changes in NF-kappaB and MAP kinase signaling, pathways involved in cellular responses to inflammatory stimuli. The study concerns specific cells and experimental models; it does not demonstrate a treatment outcome in people.

Dalmasso and colleagues in Gastroenterology 2008

A nanoparticle formulation in 2017

Xiao and colleagues incorporated KPV into polymer nanoparticles modified with hyaluronic acid. Their work examined cellular uptake and inflammatory measurements in laboratory systems and a mouse colitis model.

This study evaluated an engineered formulation. Its results cannot be attributed to every KPV preparation, because the carrier, composition, and experimental conditions contributed to the system being tested.

Xiao and colleagues in Molecular Therapy 2017

What remains unresolved

The selected evidence is preclinical. Human-derived cells grown in a laboratory are not a human clinical trial, and a chemically induced animal model cannot establish human safety or effectiveness. The complete mechanism may also differ with cell type, peptide form, and experimental conditions.

A short amino acid sequence does not, by itself, establish safety or biological equivalence across preparations. Sequence, terminal modifications, salt form, and material characterization all matter when deciding whether two experiments can be compared.

Regulatory context

In its 2026 compounding assessment of KPV and KPV acetate, FDA reported that it had not identified human clinical studies or exposure data sufficient to assess safety and effectiveness. The assessment also raised concerns about inconsistent chemical identification and incomplete characterization of materials.

That assessment addresses drug compounding. Advisory committee discussion or a compounding recommendation is not FDA approval of a medicine. Research labeling likewise does not establish approval, safety, or permission for another intended use.

FDA assessment of KPV and KPV acetate

Research and regulatory sources checked October 13, 2026.

DISCLAIMER: These statements are for research purposes only and have not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease.

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