FDA's 2026 review found no human clinical, pharmacokinetic or adverse event data for KPV; its anti-inflammatory evidence comes from mouse and rat models and cell studies[1].
A three-amino-acid fragment of the hormone alpha-MSH that calms inflammation in mouse colitis and wound models, but has never been tested in a human trial.
Overview
KPV is the tripeptide lysine-proline-valine, the last three amino acids of alpha-melanocyte-stimulating hormone (alpha-MSH), a pituitary hormone with both skin-darkening and anti-inflammatory effects[1]. Researchers noticed in the late 1980s that this tiny C-terminal piece kept much of alpha-MSH's anti-inflammatory activity on its own[1]. Because it is so small, it does not appear to act on the melanocortin receptors that drive tanning[1].
Most of the interest in KPV comes from mouse studies of inflammatory bowel disease, where oral KPV reduced chemically induced colitis[2,3,4], and from rodent wound and eye-surface models[1]. In 2026, FDA reviewed KPV and found no human data of any kind, and recommended against adding it to the list of substances pharmacies may compound[1]. An FDA advisory committee voted the other way[5,6].
Mechanism of Action
Full alpha-MSH calms inflammation mainly by activating melanocortin receptors, especially MC1R, on immune cells. KPV seems to work differently. In receptor studies it did not displace alpha-MSH from its binding sites or raise cAMP in MC1R-bearing macrophages, and experiments did not implicate MC2, MC3 or MC4 receptors in its effects[1]. Instead, the leading explanation is that KPV gets inside cells and acts there. In intestinal epithelial cells and T cells, nanomolar concentrations of KPV reduced activation of NF-kappaB and MAP kinase signaling and lowered secretion of pro-inflammatory cytokines[2].
The route into the cell appears to be PepT1, a transporter that normally absorbs di- and tripeptides from digested food and that becomes more abundant in the inflamed colon. The anti-inflammatory effect in cells depended on PepT1, which also helps explain why oral KPV worked in mouse colitis[2]. Researchers later packaged KPV into colon-targeted nanoparticles to concentrate it in inflamed tissue[4]. For skin, KPV penetrates poorly on its own; in human cadaver skin, only techniques such as iontophoresis or microneedle abrasion pushed it into the deeper epidermis[1].
What the Research Shows
- None published. FDA's 2026 review identified no human clinical trials, pharmacokinetic studies, published reports of human use, or adverse event reports (FAERS searched through December 3, 2025) for KPV in any form[1].
- Mice, DSS- and TNBS-induced colitis: KPV given in drinking water reduced colitis and lowered expression of pro-inflammatory cytokines in both models[2].
- Mice, models of inflammatory bowel disease (2008): a second, independent group reported anti-inflammatory effects of KPV in murine colitis[3].
- Mice, colitis with colon-targeted nanoparticles: KPV loaded into nanoparticles and delivered orally in a hydrogel reduced colitis, part of an effort to deliver it locally[4].
- Rodents, wound and corneal healing: FDA's review cites rodent studies reporting faster wound and corneal epithelial healing with KPV, without species-level detail on effect sizes[1].
- Human intestinal epithelial cells and Jurkat T cells: nanomolar KPV reduced NF-kappaB and MAP kinase activation and pro-inflammatory cytokine release, effects dependent on the PepT1 transporter[2].
- Receptor binding: KPV did not displace radiolabeled alpha-MSH or raise cAMP in MC1R-expressing macrophages, pointing away from classic melanocortin receptor signaling[1].
KPV is a plausible anti-inflammatory candidate with a consistent signal in mouse colitis[2,3,4], but nothing is known about how it behaves in people: how much is absorbed, how long it lasts, or whether it helps any human disease[1]. Mouse colitis models often fail to predict results in Crohn's disease or ulcerative colitis. Until human studies exist, any claims about gut, skin or joint benefits rest on animal and cell data alone, and established treatments for these conditions already exist[1].
- No human safety data: no clinical trials, case reports or FAERS reports have been identified[1].
- No formal toxicology: FDA found no acute, repeat-dose, genotoxicity, reproductive or carcinogenicity studies, and no in vivo pharmacokinetic studies[1].
- Immunogenicity and aggregation: FDA concluded there are insufficient data to rule out these risks for injected KPV[1].
- Product quality: FDA reported missing impurity, aggregate and microbiological testing in the materials submitted, and identified degradation products under stress conditions[1].
Open Questions
- Whether KPV is absorbed, reaches target tissue, or helps any human condition has never been measured[1].
- The PepT1 mechanism comes largely from one research group's cell and mouse work; independent confirmation in human tissue is limited[2,4].
- Effects of long-term use on immune defense against infection are unstudied.
- Topical use is limited by poor skin penetration, and it is unknown whether enhanced delivery raises systemic exposure[1].
Regulatory Status
Not FDA approved. KPV was removed from FDA's Category 2 compounding safety-risk list in April 2026 after its nomination was withdrawn; FDA staff recommended against adding it to the 503A bulks list, but the advisory committee voted 8-6 on July 23, 2026 to recommend it, and rulemaking has not been completed[1,5,6,7]. KPV is not named on the WADA list, but unapproved substances fall under WADA's S0 category[8].
Related Compounds
References (8)
- U.S. Food and Drug Administration. KPV (free base) and KPV acetate: FDA briefing document, Pharmacy Compounding Advisory Committee, July 23, 2026. 2026. fda.gov
- Dalmasso G, Charrier-Hisamuddin L, Nguyen HT, et al. PepT1-mediated tripeptide KPV uptake reduces intestinal inflammation. Gastroenterology. 2008;134(1):166-78. PMID: 18061177
- Kannengiesser K, Maaser C, Heidemann J, et al. Melanocortin-derived tripeptide KPV has anti-inflammatory potential in murine models of inflammatory bowel disease. Inflamm Bowel Dis. 2008;14(3):324-31. DOI: 10.1002/ibd.20334
- Laroui H, Dalmasso G, Nguyen HT, et al. Drug-loaded nanoparticles targeted to the colon with polysaccharide hydrogel reduce colitis in a mouse model. Gastroenterology. 2010;138(3):843-53.e2. DOI: 10.1053/j.gastro.2009.11.003
- U.S. Food and Drug Administration. July 23-24, 2026: Meeting of the Pharmacy Compounding Advisory Committee. 2026. fda.gov
- McDermott Will & Schulte. Bulk-list bound? PCAC backs majority of peptides in two-day public meeting. July 2026. mcdermottlaw.com
- U.S. Food and Drug Administration. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (content current as of April 22, 2026). fda.gov
- World Anti-Doping Agency. 2026 Prohibited List, S0 Non-approved substances. wada-ama.org
Sources last reviewed October 2026.