Where to buy KPV Peptide: sizes, price per mg and how to verify the lot

What "kpv peptide" names, and what it does not

KPV is three residues, lysine, proline and valine, written Lys-Pro-Val: the C-terminal tail of alpha-melanocyte-stimulating hormone, a thirteen-residue hormone of which this is residues 11 to 13. Formula C16H30N4O4, average mass 342.4 Da, PubChem CID 125672. The papers cited at the foot of this page are cell and animal work on the tripeptide delivered in various carriers. Listings write KPV, KPV peptide, KPV acetate and alpha-MSH (11-13); one molecule. It is also the fourth component of the KLOW blend, where it sits two daltons from GHK-Cu and has to be told apart from it.

As a three-residue piece of a thirteen-residue hormone it does not do everything the whole hormone does and should not be described as if it did; this page makes no claim about what it does at all. What it can say exactly is the chemistry of a very small basic peptide, which sets three buying rules that most listings ignore: the mass is low enough to be matched by accident, the peptide has no chromophore for the usual purity wavelength, and the counter-ion is a large share of the powder.

Those three rules mean a KPV certificate is read differently from one for a long peptide. A single low mass is expected and not much evidence on its own; the chromatogram must be run at 210 to 220 nm; and the net content line, with the salt named, is the number that turns a 10 mg label into a quantity. None of the three is exotic; all three are routinely skipped on certificates written from a template.

The reference point for identity is public. PubChem lists Lys-Pro-Val as CID 125672 with molecular formula C16H30N4O4, an average molecular weight of 342.43 Da and a monoisotopic mass of 342.227 Da. Those are the numbers a mass spectrometer is checked against, and the number a certificate must print beside the observed mass.

In plain terms: A man-made three-building-block peptide, the tail end of the hormone alpha-MSH. No approved product. As a three-building-block piece it does not do everything the whole hormone does, and should not be described as if it did.

KPV for sale: sizes and price per mg

LabFirst lists KPV in one size (10mg) from $49, priced per vial with the per-mg figure beside it so sizes can be compared without arithmetic. It is sold in one size, 10mg, at $4.90 per mg.

The volume tiers are per size, not per basket: ten vials of one size take 10% off that line and twenty take 15%, and mixed sizes do not combine. Shipping is a flat $15 on orders under $200 and free from $200, within the United States only, with same-day dispatch on orders placed before 12 PM Pacific on a business day. The cost per mg tool runs the same comparison across any two listings, ours or anyone else's.

A tripeptide of ordinary residues is about the cheapest thing a peptide factory makes, and KPV is priced accordingly, with the vial, the fill and the laboratory run making up nearly all of the cost; that is why LabFirst lists a 10 mg vial rather than single-digit sizes. A laboratory that will use the material buys it and reads the net content line; one qualifying a lot reads the salt, the wavelength and the mass to two decimals on the certificate before buying more.

The price signal is the salt. Two 10 mg listings at different prices can be the same tripeptide with different counter-ions and a quarter's difference in peptide content, so the cheaper vial is not cheaper until the net content line says so. Compare per milligram of peptide, not per milligram of powder. The only discounts on this page are the volume tiers, per size and unchanged month to month, and the lot on the vial is whatever the certificate index says on the day.

The certificate a KPV lot must carry

Three tests answer three different questions, and a certificate of analysis for KPV is only complete when it carries all three for the exact lot on the vial. Identity is settled by mass spectrometry, and the number to look for on a KPV certificate is 342.227 Da monoisotopic (or 342.43 Da average, if the laboratory reports the deconvoluted average mass). The observed mass should sit within the instrument's stated tolerance of that figure, and the certificate should print both the theoretical and the observed value, not just a tick.

Purity is a separate question, answered by HPLC: how much of what came off the column was the compound. The figure is only interpretable with its method beside it (column, gradient, detection wavelength) and a date, which is what ICH Q2(R2) means when it asks that an analytical procedure be shown fit for its purpose. A percentage with no method and no date is a number somebody typed, and a certificate that carries every test but for a different lot number than the vial is the most common failure of all and the easiest to catch. Net content is the third test and the one most often missing: the milligrams of KPV actually in the vial, measured, against the size printed on the label.

Identity is the observed mass against 342.227 Da monoisotopic (342.4 Da average), seen in electrospray as m/z 343.2 for the singly charged ion; the certificate should print the theoretical and observed values to two decimals, because at this mass a rounded 342 could be several unrelated small molecules and a resolved 342.23 is specific. The dipeptide deletions, Lys-Pro at 243 Da and Pro-Val at 214 Da, are the impurities to rule out. A laboratory that also reports a tandem mass spectrum showing the Lys-Pro-Val sequence has identified the tripeptide beyond doubt, and for such a small molecule that is worth asking for.

Purity by HPLC on KPV has a wrinkle that catches template certificates: the peptide contains no tryptophan, tyrosine or phenylalanine, so it barely absorbs at 280 nm, and the chromatogram must be run at 210 to 220 nm where the peptide bond absorbs. A certificate quoting a 280 nm purity for KPV has measured something else or copied a form. Net content is the line that pays: the lysine and the free N-terminus hold two counter-ions on a 342 Da molecule, so a trifluoroacetate lot can be a quarter salt by weight, and quantitative HPLC against a standard or amino acid analysis is what says how many of the labelled milligrams are peptide.

Where to buy KPV: five checks before you order from anyone

Every seller of kpv peptide says "third-party tested". The phrase costs nothing. These five checks take about four minutes per listing and separate a tested lot from a tested-sounding one.

1. The lot on the vial is the lot on the certificate. Read the printed lot number, then open the certificate and match it. A certificate for "KPV" with no lot, or a lot that does not match, describes some other vial.
2. The laboratory is named and has its own lookup. The report should come from a laboratory the seller does not own, with a search code you can enter on the laboratory's own site. LabFirst lots are tested by Freedom Diagnostics and looked up by accession number; anything that can only be verified on the seller's own page has not been verified.
3. The theoretical mass is printed, and it is the right one. For KPV that is 342.227 Da monoisotopic; a certificate that prints a different figure has either measured a different molecule or copied a template.
4. Purity has a method and a date. An HPLC percentage should name the method and the run date. A figure that reads "99%+" with neither, or one date reused across every product a seller lists, is decoration.
5. Net content is stated in milligrams. The label size is a claim; the certificate's net content is the measurement. If the certificate has no net content line, the purity figure describes the powder, not the vial, and the price per mg you calculated is fiction.

How listings for KPV specifically mislead:

• A purity figure read at 280 nm. KPV has no aromatic residue and barely absorbs there; a real KPV chromatogram is run at 210 to 220 nm, and a 280 nm figure describes a template, not the vial.
• A mass rounded to 342. At this size a rounded figure matches several unrelated small molecules; a certificate should print 342.23 against 342.227, and a tandem spectrum settles the sequence.
• A 10 mg label with no salt form and no net content. Two counter-ions on a 342 Da peptide can be a quarter of the powder by weight; without the content line the milligrams are unknown.
• "Pharmaceutical grade KPV". There is no USP monograph and no approved product; the FDA placed KPV in Category 2 of its 503A list in September 2023, so no pharmacy may compound it.

How to verify a LabFirst KPV lot

The KPV sizes in stock today carry lot LF-2608-16. Lot LF-2608-16 is at Freedom Diagnostics on accession FD-2026-05716 for identity, purity and net content. Until the report is attached the product page says "pending verification" against that lot and makes no purity claim; the price stands and the report goes live the day it arrives, on the page, at /coa/, and inside the receipt and packing slip for every order of that lot.

Verification runs through the laboratory, not through us. Open the certificate index, find the lot, and use the accession number on the Freedom Diagnostics lookup page; the report you see there is the laboratory's copy, not ours. Each lot also carries a Finnrick verify link, and every receipt and packing slip states that a customer may submit a sealed vial to Finnrick's free testing programme with the order as proof of purchase, so the brand's public record is built from vials we did not choose.

The product page reads the live stock feed on load (stock, lot and certificate state for every size), so what you see when you order is what ships. The lot is printed on the label and encoded in the QR patch on its right-hand side; scanning it opens that lot's record.

Storage and shipping for KPV

KPV is a robust peptide: nothing in it oxidises, deamidates or scrambles, and lyophilised at 2 to 8 C out of light it keeps for the full shelf period on the certificate and beyond. In solution it is similarly forgiving, though a laboratory dates its solutions and keeps its own record because robust is a comparison, not a number. Its one real weakness is water: a small basic peptide with two counter-ions is hygroscopic, takes moisture from humid air the moment the vial is opened, and a cake that has absorbed water no longer weighs what the label says, which on a 342 Da peptide with a large salt share matters more than usual. Open a vial once, for its purpose, and never re-seal one for storage.

Orders ship within the United States, flat $15 under $200 and free above it, same day when placed before 12 PM Pacific on a business day, and the shipping page states the cutoff, the carriers and what is and is not promised.

The record a laboratory keeps on arrival is what makes the certificate usable later, and it is short:

• the lot number as printed on the vial, and the certificate's accession or search code beside it;
• the date received and the condition of the seal;
• the storage location and temperature it went into;
• the number of vials, and later the date each one was opened and by whom.

A KPV vial with that record behind it can be traced from the bench to the laboratory report in one step; without it, the certificate is a document about a vial that can no longer be identified.

Regulatory status, and what this page is not

No approved medicine contains KPV and no USP or Ph. Eur. monograph defines an acceptable lot. In September 2023 the FDA placed KPV in Category 2 of its interim list of bulk drug substances nominated for compounding under section 503A, the category for substances it has identified as raising significant safety risks, which bars licensed pharmacies from compounding with it. That listing concerns pharmacies, not laboratory material, and is quoted because "pharmacy grade" appears in listings for a substance no pharmacy may currently compound.

FOR LABORATORY AND IN-VITRO RESEARCH USE ONLY. NOT FOR HUMAN OR ANIMAL CONSUMPTION. LabFirst sells KPV to laboratories and researchers as material for in-vitro work, gives no guidance on use, and ships only against that understanding. Nothing on this page or on the product page describes preparing or administering anything.

What is KPV studied for?

Published research on KPV investigates the areas below — which is a different question from what KPV will do for anyone, a claim about a living system that nothing on this site is sold for.

What it is. A man-made three-building-block peptide, the tail end of the hormone alpha-MSH.

What the research looks at. It appears in animal and cell research on inflammation.

How it is thought to work. It matches the last three building blocks of alpha-melanocyte-stimulating hormone. Published work covers melanocortin-related signalling in cells and animals, and the details are not settled.

What is not established. No approved product. As a three-building-block piece it does not do everything the whole hormone does, and should not be described as if it did.

The full record, including the certificate for the lot in stock, is on the KPV product page.

Common questions

Sources

• PubChem, Lys-Pro-Val, CID 125672. Public record for the molecular formula (C16H30N4O4), average molecular weight (342.43 Da) and monoisotopic mass (342.227 Da) quoted here as the identity reference.
• Xiao and colleagues, Orally targeted delivery of tripeptide KPV via hyaluronic acid-functionalized nanoparticles efficiently alleviates ulcerative colitis, Molecular Therapy 2017. Primary description of the compound in the literature; supports the class and naming stated here, not any use.
• Wu and colleagues, A PepT1 mediated medicinal nano-system for targeted delivery of cyclosporine A to alleviate acute severe ulcerative colitis, Biomaterials Science 2019. Primary description of the compound in the literature; supports the class and naming stated here, not any use.
• Alliance for Pharmacy Compounding, 503A Categories Update, 29 September 2023 2023-09-29. Lists the substances the FDA moved to Category 2 on that date, including KPV.
• ICH Q2(R2), Validation of Analytical Procedures (2023) 2023-11. Why a purity figure is only interpretable with its method, and what "fit for purpose" means for the HPLC and mass spectrometry results a certificate reports.
• Freedom Diagnostics, certificate lookup by accession number. The laboratory-side lookup a LabFirst lot is verified on; the report there is the laboratory copy, not ours.
• Finnrick, verify a vendor or lot. Independent verification page linked from every LabFirst lot; customers may submit sealed vials with their order as proof of purchase.