Single component
KPV
α-MSH (11-13), Lys-Pro-Val
The three C-terminal residues of α-melanocyte-stimulating hormone — lysine, proline, valine. The K in KLOW is this peptide. It is supplied as a trifluoroacetate salt, so the labelled mass and the peptide mass are not the same number.
Identity
The molecule.
- Formula
- C16H30N4O4 · CF3COOH
- Molecular weight
- 456.5 · trifluoroacetate salt (free peptide 342.4)
- Sequence
- Lys-Pro-Val
This ships as a salt, so the mg on the label is not all peptide. Every calculation that divides mg by mL carries that gap forward. Check what your supplier actually weighed.
Solubility
How much water it needs.
Source: Cayman Chemical product page 45458 (opened 2026-08-20)
Cross-check: Cayman states this as a qualitative band, not a measured maximum, and links its own note on variance in solubility. A band has no molarity to cross-check against, so it does not clear the [supplier] bar the other three components do.
Not used in the calculatorThe only number we could find is a rough range in PBS, a lab salt solution: 1 to 10 mg/mL. That is not a measured maximum in water. Take the low end and 10 mg of KPV would need 10 mL to dissolve. That is more than a standard vial holds, and more than you can mix without moving the powder into another sterile container. Taking the high end instead would just be picking whichever number makes the feature work. So we don't use it at all. For KLOW, tell us how much water you added and we'll tell you which line it lands on.
The label mass
A quarter of it is not peptide.
KPV is supplied as a trifluoroacetate salt. The salt weighs more than the peptide inside it, so a milligram of powder is not a milligram of KPV.
- Salt (what is weighed)
- 456.5 g/mol
- Free peptide
- 342.4 g/mol
- Peptide fraction
- 342.4 ÷ 456.5 = 75%
So a vial labelled 10 mg of KPV, if the supplier weighed the salt, holds 7.50 mg of KPV and 2.50 mg of salt. That gap is bigger than most of the measuring errors people worry about.
Nothing on an unbranded vial tells you which one they weighed. The calculator uses the number you type in, and never converts between the two behind your back.
Storage
Keeping it.
−20°C as supplied. Refrigerate after reconstitution.
We print no beyond-use date. Why that number is missing
The papers
What the research studied.
Every paper here is on PubMed and you can open it yourself. They all studied KPV on its own, not in a blend, and mostly in animals.
- Xiao B, Xu Z, Viennois E, et al.2017Molecular TherapyAnimal study
Orally Targeted Delivery of Tripeptide KPV via Hyaluronic Acid-Functionalized Nanoparticles Efficiently Alleviates Ulcerative Colitis
Loaded KPV into hyaluronic-acid-functionalised polymeric nanoparticles and delivered it orally in a colitis model. KPV is a naturally occurring tripeptide — lysine, proline, valine.
PMID 28143741 →
The name
What else it gets called.
KPV is the short form; the full name is α-MSH (11-13), Lys-Pro-Val. Suppliers and forum posts use these interchangeably and search engines treat them as separate things, so a figure you found under one of the other names was still about this molecule.
- KPV peptide
- Lys-Pro-Val-OH
- tripeptide KPV
- alpha-MSH (11-13)
What we could not source
The gaps, named.
Every figure above says where it came from. These are the ones we went looking for and could not find. Each one ends with what we do about it. Admitting you do not know something and then carrying on regardless is not admitting anything.
How much KPV will actually dissolve in water
The best figure out there is "Sparingly soluble: 1–10 mg/mL" in PBS (pH 7.2). That is a rough band rather than a measured number, and it was not measured in water.
What we do So we never work out the water for a vial with KPV in it. You give us the volume, and we tell you which line on the syringe that lands on.
Whether your supplier weighed the salt or the peptide itself
KPV ships as a salt, and only 75% of that weight is the actual peptide. So a vial labelled 10 mg by salt weight holds 75% of that in real KPV. Nothing on an unbranded vial tells you which one they weighed.
What we do So we use whatever number you type in and never quietly convert between the two. If you want the peptide weight, do the conversion before you type it in.
A CAS number for KPV — the official chemical ID
We could not find one printed on a supplier page that we opened ourselves. Numbers floating around in forum posts are not something we are willing to copy.
What we do So we leave the field off this page entirely, rather than fill it in with a number we have not checked.
How long KPV keeps once mixed, in a normal fridge
Suppliers give you storage conditions for the dry powder in a −20 °C freezer. Nothing we found says anything about a mixed vial sitting at 2–8 °C.
What we do So we print no use-by date and no countdown, anywhere on this site or in anything you download.
Where it appears
Blends that contain KPV.
KPV 10 mg
Also written as KPV peptide · Lys-Pro-Val-OH · tripeptide KPV · alpha-MSH (11-13).
KPV is a research chemical, not an approved medicine. This page describes the molecule and how to handle it; it makes no claim about what KPV does. Not medical advice.