KPV (Lys-Pro-Val; alpha-MSH 11-13)
KPV: What The Studies Actually Say
KPV is sold online for gut, skin and histamine problems. Every study of it was done in lab dishes or animals. FDA found no human data at all. Here is what those studies actually found.
Updated 22 September 2026
Before you read this
This page explains what published studies found. That is all it is. It is not medical advice, and it is not instructions for using anything. Nothing here is meant to find, treat, cure or stop any illness. The compounds discussed on this site, retatrutide included, are not approved by the FDA for use in people. Research compounds are sold for laboratory use only — not for use in humans or animals. A study tells you what happened to the people in it. It does not tell you what would happen to you. What you do with what you read here is your responsibility, so talk to a doctor first. This page is published by Ascend Vials, which sells research compounds.
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FDA went looking for any study of KPV in people. It found none.
Everything you have heard about it comes from lab dishes, mice and rabbits. Here is what that research actually found. Every claim has a link. Read them yourself.
The 30-second version
- KPV is a tiny lab-made peptide: three amino acids copied from the end of a natural hormone called alpha-MSH.
- Every result comes from lab dishes and animals. FDA found no human data at all, by any route.
- In mice with an inflamed colon, it cut a marker of inflammation by about 30% to 50%. The groups were 5 to 10 mice.
- Nobody knows how it works or what amount would be safe. The standard safety tests have never been done.
- It is not an approved medicine in the US, and FDA found no approved product in the EU. An FDA advisory panel voted 8 to 6 to recommend letting pharmacies make it for skin use. That vote is only advice. FDA's own staff argued against it.
- Nothing sold online has been shown to match what the studies used. No study has checked.
What it is
KPV is three amino acids joined in a row: lysine, proline and valine. They are the last three pieces of alpha-MSH, a natural hormone. Journal of Leukocyte Biology, 2000
It is sold in two forms, a "free base" and an "acetate" salt, which FDA treats as two different ingredients. "KPV" is a nickname, not an official drug name. It is not in any FDA-approved drug. FDA review, 2026
FDA found it sold online as injections, pills, skin products and nasal sprays. The claims included colitis, Crohn's, wound healing, psoriasis, mast-cell problems and histamine intolerance. FDA review, 2026
Not one study in a person
In FDA's own words: "FDA has not identified any human exposure data on drug products containing KPV administered via any route of administration." FDA, 2026
A search of the US trial registry on September 22, 2026 found no registered KPV trials. ClinicalTrials.gov
The closest KPV has come to a person is a test tube: blood from people with HIV, with KPV added in the lab. It lowered two inflammation signals. No patient took any. Peptides, 1998
A mouse result tells scientists what to test next in people. It does not tell you what happens in a person.
The gut studies, all in mice
Five teams tested KPV in mice with an inflamed colon, usually inflamed on purpose with a chemical. Gastroenterology, 2008
| Study | Mice per group | How long | What happened |
|---|---|---|---|
| Dalmasso, 2008 | 5 to 10 | 2 to 8 days | Less inflammation, less weight loss |
| Kannengiesser, 2008 | Not given | Not given | Faster recovery, better weight regain |
| Laroui, 2010 | Not given | Not given | Less inflammation, with KPV packed in tiny particles |
| Xiao, 2017 | 5 | 8 days | Coated particles did best. No mice got plain KPV |
| Viennois, 2016 | 5 to 6 | 6 to 13 weeks | Fewer, smaller tumors — but not in every model |
Read the middle columns. Five or ten mice per group, for days or weeks. Two studies do not give a group size we could check.
The first study in the table put KPV in the mice's drinking water. It cut the rise in myeloperoxidase — a marker of white blood cells piling into the gut — by about 50% in one colitis model and about 30% in the other. Gastroenterology, 2008
The particles are a lab formulation, not plain KPV. One team reports they worked about as well as plain KPV in solution, at a concentration 12,000 times lower. Gastroenterology, 2010 The other gave no mouse plain KPV at all. Molecular Therapy, 2017
In the tumor study, the paper gives no exact figures for the drop. KPV made no significant difference in mice bred without PepT1, a doorway that carries tiny peptides into cells. Nor did it reduce tumors caused by a faulty gene instead of inflammation. Cell Mol Gastroenterol Hepatol, 2016
None of these models is ulcerative colitis or Crohn's disease in a person. Nobody knows whether the results carry over.
Skin, eyes, brain and germs
Skin. This matters most, because FDA's 2026 review was about KPV on the skin. FDA review, 2026 On human skin in a lab, no detectable KPV got through on its own. It got through only after microneedles or a weak electric current. Journal of Pharmaceutical Sciences, 2017 FDA says that could mean less reaches the body from a skin product — or that the product does not work. FDA review, 2026
Eyes. Rabbits had the surface of the cornea scraped off. By 60 hours, 8 of 8 corneas given KPV drops or a nitric-oxide drug (used for comparison) had fully regrown their surface. None on placebo had. Experimental Eye Research, 2006
Brain. In an exploratory study, mice got one KPV injection 30 minutes after a brain injury. A day later the damaged area was about 24% smaller, with about half as many dying brain cells. But the mice did not score significantly better on a test of brain function. PLOS ONE, 2013
Germs. In lab dishes, KPV slowed Staph bacteria and a yeast called Candida. Journal of Leukocyte Biology, 2000 At higher concentrations it killed more than 90% of Staph cells, including drug-resistant MRSA. Antimicrob Agents Chemother, 2011 A dish is not a body.
How it works: nobody is sure
FDA's 2026 review says the targets KPV acts on "remain unknown." FDA review, 2026
It does not seem to use alpha-MSH's usual docking points on cells, the melanocortin receptors. Biochemical Pharmacology, 2001 · J Pharmacol Exp Ther, 2003 One study points the other way. Elliott, 2004
Another idea: PepT1, that doorway for tiny peptides, carries KPV into gut and immune cells. Inside cells, KPV blocks NF-κB, a switch that turns on inflammation genes. Gastroenterology, 2008 · Airway cells, 2012 PepT1 is low in a healthy colon and rises in inflammatory bowel disease. Cell Mol Gastroenterol Hepatol, 2016
All of this comes from cells and animals.
What about side effects? Nobody has looked
In FDA's words: "FDA lacks important information regarding any safety issues raised by KPV, including whether it would cause harm if administered to humans." FDA, 2026
FDA's 2026 review found no studies at all on any of these: FDA review, 2026
- harm from one dose, or from repeated doses
- damage to genes
- effects on fertility or unborn babies
- cancer risk
- how the body absorbs and clears it, in animals or in people
No reports is not the same as safe. FDA's side-effect database has no KPV reports. But reporting is voluntary, compounders generally do not report, and FDA says that database alone cannot settle safety. FDA review, 2026
Nobody has tested whether KPV clumps together or sets off the immune system. FDA notes that peptides as short as two amino acids can clump, and clumping raises the risk of immune reactions. FDA review, 2026
Is it approved?
No. KPV is not an FDA-approved drug or part of one. FDA found no approved product in Europe, and no KPV entry in the official European or Japanese drug standards. FDA review, 2026 Other countries, like Australia, Canada and the UK, we have not checked against official sources.
The compounding story, in order:
- In 2023, FDA put KPV on its list of compounding ingredients that "may present significant safety risks." FDA, archived 2024 The only formal request to allow it, a skin cream or gel, was later withdrawn. FDA, 2026
- FDA reviewed it anyway, for use on the skin. Its staff concluded the evidence weighs against letting pharmacies compound it. FDA review, 2026
- On July 23, 2026, FDA's advisory committee met. It voted 8 yes, 6 no, 1 abstaining, to recommend allowing it. That count is from a law firm's summary. McDermott, 2026 FDA's own meeting page still showed no minutes or vote results on September 22, 2026. FDA meeting page
- The vote is only advice. Pharmacies still cannot legally compound these peptides until FDA finishes a formal rule, or Congress changes the law. Holland & Knight, 2026 By September 22, 2026, no rule had been proposed. The only federal notice naming KPV was the meeting announcement. Federal Register, 2026
Sport. KPV is not named on the World Anti-Doping Agency's 2026 banned list. But the list bans any substance it does not cover elsewhere that no government has approved for human use. That seems to cover KPV. That is our reading, not a WADA ruling. WADA, 2026 · 2026 list, PDF
What is still unknown
- Whether KPV does anything in people, for anything.
- How the human body handles it: whether it survives the stomach, how much reaches the blood, how long it lasts.
- A human dose. Every dose you see online is a guess. No mouse amount has been translated to people.
- Long-term safety, including cancer risk and effects on pregnancy.
- Whether it changes skin colour. Its parent hormone drives skin pigment. KPV has not been tested.
- How it mixes with other drugs, including standard treatments for inflammatory bowel disease.
- Whether your body makes free KPV at meaningful levels. FDA's review says it does, but its only source is a functional-medicine website.
What is in the bottle is not what was studied
One more thing.
Every KPV result on this page came from a lab experiment. Cells in a dish. Mice. Rabbits. None of it tested a product sold online.
And FDA found that "KPV" is a loose label: FDA review, 2026
- Several salts and variants are sold under the name, some with a different active molecule.
- Most public references give the free base and the acetate the same CAS number, so that number cannot tell them apart.
- The only formal nomination's certificate of analysis named one form but gave the other's chemical formula. It had no tests for clumping or germs.
- In stress tests, KPV acetate broke down into other chemicals, some never identified.
FDA judged both forms "not well-characterized."
No study has ever shown that a product sold online as "KPV" is the same thing the studies used. Not the same purity. Not the same form. Not even proof it is the same molecule.
So take every number on this page for what it is. It describes lab KPV in cells and animals. It describes nothing else.
How to check a number yourself
You are going to see more claims about KPV. In a reel. In a comment. On somebody's store page.
Here is how to tell a real one from a marketing one. Five questions. About ten seconds each.
1. Is there a link to a study?
A real number comes from a paper you can open. No link means it is a claim, not a result. Search the name on pubmed.gov yourself. If nothing comes back, nothing was published.
2. Was it done in people?
The big one for KPV. Look for "mice" or "cells" near the top of the paper. A mouse result is a reason to run a human study. It is not a human result.
3. How many animals, and for how long?
Small studies swing. The KPV gut studies used 5 to 10 mice per group, for days or weeks. If a summary does not say how many, notice that.
4. Was it the same thing that is sold?
Some KPV results came from tiny particles built for the colon, or from eye drops on scraped rabbit eyes. They may not carry over to plain KPV.
5. Where did the claim come from?
FDA found KPV sold for mast-cell problems, histamine intolerance, psoriasis and more. It found no human data at all behind any of them. FDA review, 2026
Now run those five on this page
Every number above links to its paper and says whether it came from cells, mice or rabbits. The group sizes are in the table. The particle and eye-drop studies are flagged.
The claims in the ads — gut, skin, histamine, mast cells — have no human study to link to, because none has been published.
That is the whole difference: a number you can check, and a number you are asked to believe.
This page has a date on it, near the top. If a human study of KPV is ever published, this page changes.
Read the studies yourself
- FDA review of KPV, 2026 — the main one
- FDA safety-risk list: current page · archived 2024
- The vote and the law: FDA meeting page · McDermott · Holland & Knight · Federal Register
- Sport: WADA 2026 list · PDF
- ClinicalTrials.gov search for KPV — no registered trials
- Gut, in mice: Dalmasso, Gastroenterology 2008 · Kannengiesser, Inflamm Bowel Dis 2008 · Laroui, Gastroenterology 2010 · Xiao, Mol Ther 2017 · Viennois, CMGH 2016
- Skin, eyes, brain: Pawar, J Pharm Sci 2017 · Bonfiglio, Exp Eye Res 2006 · Schaible, PLOS ONE 2013
- Germs: Cutuli, J Leukoc Biol 2000 · Singh, Antimicrob Agents Chemother 2011
- How it works: Mandrika, Biochem Pharmacol 2001 · Getting, J Pharmacol Exp Ther 2003 · Elliott 2004 · Land, Int J Physiol Pathophysiol Pharmacol 2012
- Human blood in a test tube: Catania, Peptides 1998
Everything above describes lab and animal experiments. None of it was done in people. This is not advice, a plan, or instructions. KPV is not an approved medicine. Research compounds are not for human or animal use.