Klotho-Derived Peptide 1 (KP1) — Safety, Research, Risks & Legal Status

Not medical advice. Klotho-Derived Peptide 1 (KP1) is discussed here for informational and harm-reduction purposes only. We do not endorse use, and any dosing context is informational, not a protocol.

Also known as	KP1, KL1-derived peptide, Klotho-derived peptide 56-87, Klotho-derived peptide Phe57-Gly86, Tocris 7830
Category	Peptide (research chemical)
Sequence length	30 amino acids (FQGTFPDGFLWAVGSAAYQTEGGWQQHGKG)
Primary target	TGF-beta receptor 2 (TbetaR2) - competitive antagonist
Development stage	Preclinical only; no FDA IND or registered human trial as of mid-2026
Research origin	Southern Medical University / University of Pittsburgh; lead investigators Youhua Liu and Lili Zhou
Catalog availability	Tocris 7830, Cayman Chemical, MedChemExpress, GenScript, TargetMol, Phoenix Pharmaceuticals
Animal models studied	Renal ischemia-reperfusion, obstructive nephropathy, CCl4 hepatotoxicity, bile duct ligation, COVID-19-associated AKI
US legal status	Not FDA-approved and not currently in clinical development. KP1 is available exclusively as a research reagent from chemical suppliers (Tocris/Bio-Techne, Cayman Chemical, Phoenix Pharmaceuticals, MedChemExpress, TargetMol, GenScript). It carries no DEA or controlled-substance designation. It is not approved for human therapeutic use in any jurisdiction known to the research literature reviewed.

What is Klotho-Derived Peptide 1 (KP1)?

Klotho-Derived Peptide 1 (KP1) is a synthetic 30-amino acid peptide (sequence: FQGTFPDGFLWAVGSAAYQTEGGWQQHGKG) designed as a mimetic of the KL1 domain of the endogenous aging-suppressor protein alpha-Klotho. It functions as a competitive inhibitor of TGF-beta signaling by directly binding TGF-beta receptor 2, and has demonstrated anti-fibrotic and anti-senescence effects in rodent models of kidney and liver injury. All human efficacy and safety data are absent; KP1 is strictly a preclinical research compound as of mid-2026.

How it works

KP1 binds directly to transforming growth factor beta receptor 2 (TbetaR2), competitively blocking TGF-beta ligand engagement. This suppresses both the canonical Smad-dependent pathway and the non-canonical MAPK-dependent pathway downstream of TGF-beta. Additionally, KP1 restores endogenous alpha-Klotho expression at the posttranscriptional level in fibrotic tissue and inhibits fibroblast activation and cellular senescence markers. Because it targets a discrete receptor-binding interface derived from an endogenous protein domain rather than disrupting systemic Klotho signaling, preclinical authors note it does not appear to alter blood phosphorus or calcium homeostasis - though this observation comes from rodent data only.

Background & history

KP1 was identified and synthesized through research led by Youhua Liu and Lili Zhou at Southern Medical University (Guangzhou, China) in collaboration with the University of Pittsburgh. The peptide sequence was derived from the KL1 domain of full-length alpha-Klotho, motivated by the challenge that the intact Klotho protein is large, difficult to manufacture at scale, and produces off-target hormonal effects when administered exogenously. Initial in vitro and murine in vivo work was published in Nature Communications in 2022, establishing the kidney fibrosis protective effect. Follow-on publications through 2024 extended findings to hepatic fibrosis models (International Journal of Biological Sciences) and COVID-19-associated acute kidney injury. The peptide is available as a commercial research reagent under catalog number Tocris 7830. No pharmaceutical company has claimed development rights or initiated a regulatory filing as of the research reviewed.

What the research says

All published evidence is preclinical. In murine models - including renal ischemia-reperfusion injury, obstructive nephropathy (unilateral ureteral obstruction), carbon tetrachloride hepatotoxicity, and bile duct ligation - KP1 administration reduced histological fibrosis scores and preserved organ function compared to controls. Pharmacokinetic studies in mice showed preferential accumulation of the peptide in injured or fibrotic tissue relative to healthy tissue, which authors interpreted as a favorable distribution profile. In cell culture, KP1 blocked TGF-beta signaling in hepatic stellate cells, kidney fibroblasts, and renal tubular epithelial cells, and inhibited senescence markers including p16 and p21. No human clinical trial data exists. A ClinicalTrials.gov record (NCT03532568) studies soluble Klotho protein in CKD-associated pruritus - this is a distinct molecule from KP1 and does not constitute clinical evidence for the peptide.

Reported effects

Anti-fibrotic in rodent kidney models (renal ischemia-reperfusion, obstructive nephropathy) - animal data only
Anti-fibrotic in rodent liver models (CCl4 hepatotoxicity, bile duct ligation) - animal data only
Inhibition of cellular senescence markers (p16, p21) in fibrotic tissue - animal and in vitro data only
Suppression of fibroblast activation and myofibroblast differentiation - in vitro data
Restoration of endogenous alpha-Klotho expression at posttranscriptional level - animal and in vitro data
Preferential accumulation in injured vs. healthy tissue in murine pharmacokinetic studies - animal data only
No human efficacy signals exist; all effects listed are from rodent models or cell culture

Dosing & administration (informational)

Published murine studies report intraperitoneal or intravenous administration at doses in the microgram-to-milligram-per-kilogram range in rodent models; exact reported ranges vary by study and model. These figures are presented here as literature context only and do not constitute a human dosing protocol. Rodent dose-to-human translation for peptides is not straightforward and cannot be made without clinical pharmacokinetic data, which does not exist for KP1. No dosing guidance for human use should be inferred from animal data. Anyone considering any investigational peptide for personal use should consult a licensed clinician.

This is general research/context information, not medical advice or a recommended protocol.

Safety & side effects

No human safety data exists - comprehensive toxicology, long-term pharmacokinetics, and clinical adverse event data are entirely absent
Preclinical authors infer the peptide may cause few adverse effects because it is derived from an endogenous protein domain; this is inference, not empirical data
Does not appear to disrupt phosphorus/calcium homeostasis in murine studies, unlike exogenous full-length Klotho protein - rodent data only
No maximum tolerated dose, NOAEL, or genotoxicity data identified in the reviewed literature
Immunogenicity risk is uncharacterized - any exogenous peptide can trigger an immune response in humans
Peptide stability, oral bioavailability, and route-of-administration tolerability in humans are unknown
Not for human consumption; sold exclusively as a research reagent

Drug & supplement interactions

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Who should avoid it

Human self-administration - no safety data, no approved formulation, no regulatory authorization
Use as a substitute for evidence-based treatment of kidney or liver disease
Inference of clinical efficacy from animal model results without human trial data
Combining with other TGF-beta pathway inhibitors without medical supervision - additive effects are unstudied
Sourcing from unverified suppliers without analytical purity documentation
Any assumption that peptide origin from an endogenous protein domain confers human safety without empirical toxicology data

How it is commonly combined

No stacking data exists for KP1 in humans. Animal studies tested KP1 as a monotherapy in isolated fibrosis models. Combination use with other compounds is entirely uninvestigated and cannot be evaluated from existing literature.

Legal & regulatory. Not FDA-approved and not currently in clinical development. KP1 is available exclusively as a research reagent from chemical suppliers (Tocris/Bio-Techne, Cayman Chemical, Phoenix Pharmaceuticals, MedChemExpress, TargetMol, GenScript). It carries no DEA or controlled-substance designation. It is not approved for human therapeutic use in any jurisdiction known to the research literature reviewed.

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Frequently asked questions

Is KP1 approved for any human use?

No. KP1 is not FDA-approved and has no regulatory approval in any jurisdiction. It is sold exclusively as a research reagent and has no legal therapeutic indication.

Has KP1 been tested in human clinical trials?

No human clinical trial data exists for KP1 as of mid-2026. All published efficacy data comes from murine animal models and in vitro cell culture. A ClinicalTrials.gov record (NCT03532568) studies soluble Klotho protein in kidney disease - this is an entirely distinct molecule and does not represent clinical evidence for KP1.

What conditions has KP1 shown effects in?

In rodent models only, KP1 has shown reduced fibrosis in kidney ischemia-reperfusion injury, obstructive nephropathy, carbon tetrachloride liver toxicity, bile duct ligation-induced hepatic fibrosis, and COVID-19-associated acute kidney injury. These are animal findings and cannot be directly extrapolated to human disease outcomes.

What is the recommended dose of KP1?

No dosing recommendation for humans can be made. Rodent studies report dosing in microgram-to-milligram per kilogram ranges via injection, but human pharmacokinetics are entirely unknown. Anyone considering any investigational compound should consult a licensed clinician before use.

Is KP1 safer than administering full-length alpha-Klotho protein?

Preclinical data suggests KP1 does not disrupt phosphorus and calcium homeostasis the way exogenous full-length Klotho protein does in mice, which authors interpret as a safety advantage. However, this comparison is based on rodent data only, and human safety for either agent is unestablished. The inference that endogenous-protein-derived peptides are inherently safe in humans is not supported by comprehensive toxicology data.

Where does KP1 stand in the drug development pipeline?

KP1 is at an early preclinical stage with no pharmaceutical sponsor, no IND application, and no registered human trial as of mid-2026. Published research from 2022 to 2024 establishes mechanism and animal efficacy, but the compound has not advanced beyond academic research. Its trajectory toward clinical development is speculative.

References & further reading

PubMed: "Klotho-derived peptide fibrosis TGF-beta signaling" - retrieves key 2022 Nature Communications and 2024 IJBS primary publications
PubMed: "KP1 kidney injury Klotho peptide" - retrieves mechanism and AKI model studies
PubMed: "alpha-Klotho KL1 domain TGF-beta receptor" - retrieves mechanistic context on receptor binding
ClinicalTrials.gov: NCT03532568 (soluble Klotho in CKD pruritus - distinct molecule, provided for context on Klotho biology in humans only, not KP1 clinical evidence)
Tocris/Bio-Techne product page for catalog number 7830 - supplier characterization data and purity specifications