KPV peptide: what it is, how it is supplied

KPV is a peptide of three amino acids (lysine, proline and valine (Lys-Pro-Val)) written with the one-letter code that gives it its name: K, P, V.

It is the last three residues of α-melanocyte-stimulating hormone (α-MSH), a 13-residue peptide; KPV is the C-terminal fragment, positions 11 to 13.

• Sequence: Lys-Pro-Val (KPV).
• Molecular weight: about 342.4 Da as the free peptide; research suppliers usually sell the acetate salt, and the certificate of analysis states which.
• Appearance: white to off-white lyophilized powder, hygroscopic.
• Parent molecule: α-MSH, of which KPV is a synthetic fragment: it is made by chemical synthesis, not extracted.

It is one of the shortest peptides sold by research suppliers, and one of the simplest to characterize: a single main peak on HPLC and a single compound for the laboratory to name.

Research use only. Not for human or veterinary use.

Further reading: GLOW peptide blend.

Research suppliers offer KPV the same way they offer any short synthetic peptide: as a lyophilized powder in a sealed glass vial with a rubber septum and an aluminum crimp cap.

The label states the compound name, the net quantity in milligrams and the words "research use only".

Because KPV is small and inexpensive to synthesize, it also turns up in cosmetic formulations at a fraction of a percent.

Those are a different object from a lyophilized vial from a certified lot, and a listing that gives no mg quantity is one of them.

For a tripeptide, the certificate is short, and every field on it is easy to check:

• The laboratory's name and a verifiable test number. Independent labs (Janoshik is the reference for this market) publish each test under a number anyone can look up.
• The lot number: with the task number and verification key the laboratory confirms.
• HPLC purity as a measured percentage. For a three-residue peptide the main peak dominates; a low figure means several by-products of similar size, which is a red flag.
• Identity and quantity: KPV named as the compound found, with the mg measured. Some labs add a mass spectrum as an option (near 342 Da for the free peptide).
• The test date and a photograph of the tested vial wearing the supplier's own label.

The full reading guide, with what an edited or re-used certificate looks like, is in how to read a peptide COA.

KPV follows the general rule for lyophilized peptides: cold, dark and dry.

• Temperature: −20 °C for long-term storage, in the sealed vial, away from light and moisture.
• Light and moisture: keep the vial sealed and in its box; let a cold vial reach room temperature before it leaves its bag so no condensation forms on the glass.
• Shelf life: suppliers typically state 24 months for a sealed vial stored as above; the date on the label governs.

Ambient shipping for a few days does not degrade the sealed powder. The rules, compound by compound, are in lyophilized peptides: storage and shelf life.

"KPV peptides" returns cosmetic brands, marketplace listings and a handful of research suppliers. Five questions sort them:

1. What does the supplier's lab documentation cover? Before buying from any supplier, check which compounds and sizes its reports name, and that each one can be looked up on the laboratory's site.
2. Is the vial sealed, with a printed label naming the compound, its net mass in mg and "research use only"?
3. Is the quantity stated in mg?
4. Does the supplier ship domestically, tracked, in a few days?
5. Does the product page describe the reagent only (composition, purity documentation, storage) with "research use only" stated plainly?

The wider checklist (payment, packaging, what to do if a parcel is stopped) is in where to buy research peptides in Europe.

The copper tripeptide GHK-Cu, another three-residue reagent, is described in the GHK-Cu buying guide. KPV is also the fourth component of the KLOW blend (80 mg vial in the catalog), 10 mg alongside BPC-157, GHK-Cu and TB-500.

Further reading: copper tripeptides and AHK-Cu copper tripeptide.

KPV is listed in the catalog as a 10 mg lyophilized vial, supplied like every other compound: a sealed, labeled vial. It ships tracked from our EU stock to European countries.

See KPV in the catalog →

α-Melanocyte-stimulating hormone is a 13-residue peptide, Ac-Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH₂.

It is cut from a larger precursor protein, pro-opiomelanocortin (POMC), which also gives rise to ACTH and the other melanocortins. KPV is the last three residues of that chain: lysine at position 11, proline at 12, valine at 13.

The fragment is interesting to chemists for a simple reason: it is short enough to synthesise cleanly, and it keeps the C-terminal end of the parent hormone without its central His-Phe-Arg-Trp core.

In published laboratory work it is studied as a separate molecule, under its own name, and that is how research suppliers list it: a tripeptide in its own vial, not "α-MSH".

Because the sequence is only three residues long, there is little room for a wrong synthesis to hide: a missing or swapped amino acid changes the mass by tens of daltons, which a mass spectrum shows at once.

"KPV" on a label does not say everything about the molecule in the vial. Three details change its mass, and a careful certificate states each of them.

• The C-terminus. In α-MSH the valine ends as an amide (-NH₂). Synthetic KPV is sold either as the free acid (Lys-Pro-Val-OH, C₁₆H₃₀N₄O₄, 342.4 g/mol) or as the amide (Lys-Pro-Val-NH₂, about 341.5 g/mol). One dalton apart: a mass spectrum separates them, an HPLC trace alone does not.
• The salt. Like most research peptides, KPV leaves the purification step as a salt, usually the acetate. The counter-ion adds weight to the powder without adding peptide.
• The water. A lyophilized powder keeps a few percent of residual moisture. Together with the salt, it is the reason the net peptide content of a vial is lower than the gross weight of the powder.

None of this is a defect. It is what the certificate is for: the compound named, its form stated, the mass confirmed, the purity measured on that lot.

A vial labelled "KPV 10 mg" should hold 10 mg of the peptide, not 10 mg of powder that includes salt and water.

Laboratories check this in one of two ways: a quantity test on the lot (the laboratory weighs the peptide content against a reference) or a net peptide content figure on the certificate.

For a tripeptide, the difference between gross weight and net peptide can be noticeable, because the acetate counter-ion is heavy relative to a 342 g/mol molecule.

That is a reason to compare suppliers on the stated net quantity, then on the price per mg, never on the price per vial.

In Europe, OXpeptides supplies KPV as one of the four components of the KLOW blend (10 mg of KPV in an 80 mg vial).

A laboratory report on a four-peptide vial shows the KPV peak next to the three others; how such a vial is analysed is explained on that page. Research use only. Not for human or veterinary use.

The "K" in KLOW is the KPV: the blend is GLOW with a fourth peptide added. On a KLOW chromatogram, the KPV is the smallest of the four molecules and usually one of the first to come off the HPLC column, with GHK.