Peptide LibraryKlotho
Also known as: α-Klotho, a-Klotho, KL protein
Klotho (also called α-Klotho or a-Klotho) is a longevity protein in the Longevity / FGF23 co-receptor class. Alpha-Klotho is a single-pass transmembrane protein expressed mainly in kidney and choroid plexus. Membrane-bound Klotho functions as an obligate co-receptor: FGF23 binds FGF receptors with low affinity alone, and Klotho is required to form a high-affinity complex, which is how FGF23 regulates phosphate excretion and vitamin D metabolism.
For research use only.
Key Facts
- CAS
- —
- Molecular Weight (MW)
- ~130 kDa (full-length protein)
- Half-life
- —
- FDA status
- Not Approved
- Evidence level
- Insufficient Evidence
- Human dose established
- No
- Administration Route
- Not established in humans
- Frequency
- Not established in humans
- Last updated
- Nov 7, 2026
- Reviewed
- Nov 7, 2026
- Targets
- FGFR/FGF23Aging-related pathways
Vendor price snapshot
Each vendor's price is the median price per mg of its own listings; with fewer than 3 vendors there is no typical range. From public vendor listings collected in Nov 2026, so confirm the live price on the vendor site. Peptide Library does not sell peptides.
- Vendors listing this peptide
- 2
- Listed offers
- 6
- Price per mg
- $7475.00/mg
Research summary
Transmembrane and soluble anti-aging protein that is an FGF23 co-receptor. Shop “Klotho” vials are not an FDA-approved drug and are often fragments or poorly characterized proteins.
Research evidence
- Regulatory review (FDA label)None in reviewed sources
- Controlled human trialsNone in reviewed sources
- Early or uncontrolled human studiesNone in reviewed sources
- Lab & animal studies2 reviewed sources
How it works
Each step shows whether the sources Peptide Library has reviewed include that kind of research. Counts are reviewed sources, not every study ever published. Reviews and programme summaries that describe human use are shown as "reported", not as trials, and registered trials without published results are listed but not counted. A higher step means research has progressed further; it does not mean a compound works better or is safer. Compounds whose evidence has not been reviewed yet show "Not reviewed" instead of a guess.
Peptide Library's Klotho profile summarises 5 cited studies listed in the Science section, the compound's regulatory status, and research-protocol parameters reported for it. It is a research reference, not medical advice.
Klotho dosage: no established human dose
Klotho has no established human dosage. It is a large protein, and klotho protein has not been given to people in any published or registered trial. Recombinant klotho has been injected into animals, for example 10 mcg/kg a day in diabetic mice and a single low dose in aged rhesus monkeys.
No established human dosage.
Human clinical evidence: None identified.
Preclinical research: Klotho is a co-receptor for FGF23 and is also shed into the blood as soluble klotho. Injected klotho protein has been studied only in animals, in mcg/kg amounts that do not convert to a human dose. Human studies of klotho mostly measure the body's own blood levels, which are not dosing evidence. The one registered interventional study is a gene therapy that delivers the klotho gene, together with follistatin, and has posted no results.
Animal dosing is not converted into a human dose anywhere on this page. Where research figures appear below, they are reported as studied, not recommended.
| Human dosing established | No |
|---|---|
| Route | Not established in humans |
| Evidence level | Insufficient Evidence |
| Last reviewed | 2026-11-07 |
Preclinical and analog research
Not human dosing evidence. Listed for completeness and never extrapolated to a human dose.
| Study / context | Population | Dose | Route | Frequency | Duration | Outcome studied | Source |
|---|---|---|---|---|---|---|---|
| Preclinical — klotho protein in aged rhesus monkeys (2023)Preclinical · Animal study (non-human primates and mice) | Aged rhesus monkeys (rhesus klotho protein first validated in mice) | A single low dose; the amount is not stated in the indexed abstract (non-human) | Not stated in the indexed abstract | Single administration | — | Low-dose klotho improved memory; a high dose did not | Longevity factor klotho enhances cognition in aged nonhuman primates. Nat Aging. 2023. |
| Preclinical — recombinant human klotho in diabetic db/db mice (2018)Preclinical · Animal study | db/db mice, a model of type 2 diabetes | 10 mcg/kg a day (non-human) | Not stated in the indexed abstract | Daily | — | Lower kidney weight, systolic blood pressure and albuminuria; no change in body weight | Klotho protein supplementation reduces blood pressure and renal hypertrophy in db/db mice, a model of type 2 diabetes. Acta Physiol (Oxf). 2019. |
| NCT07285629 — klotho and follistatin plasmid gene therapy, not klotho proteinClinical trial · Early phase 1 gene therapy study, single arm, completed; it delivers the gene, not the proteinStudied an analog, not Klotho itself | Healthy adult volunteers (n=14) | Plasmid gene therapy; not a protein dose | Subcutaneous injection of a nonviral plasmid into abdominal fat | — | — | Safety, cognitive and health measures before and after; no results posted | NCT07285629 — Safety and Efficacy of Klotho and Follistatin Gene Therapy |
Where sources disagree
- Products sold as klotho vary in what they contain: full-length protein, a fragment, or poorly characterised material. Animal results with a defined recombinant protein do not describe these products.
- The klotho and follistatin plasmid study gives a gene, not the protein, and was run outside the US. It is not evidence for a klotho protein dose.
Reconstitution
Common research vial sizes: 20 mcg (0.02 mg).
| Vial | Bacteriostatic water | Concentration | Per 0.01 mL |
|---|---|---|---|
| 20 mcg (0.02 mg) | 1 mL | 20 mcg/mL | 0.2 mcg per 0.01 mL |
These figures are arithmetic only — they convert a vial and a volume into a concentration. They are not a recommendation to take any dose.
Calculate reconstitution & dose →Handling & administration
- Injection Sites
- AbdomenThigh
- Timing Notes
- Educational catalog only — not medical advice
Sequence & molecular data
| Molecular weight | ~130 kDa (full-length protein) |
|---|---|
| Appearance | White lyophilized powder |
| Formulation | Lyophilized Powder |
Identifiers link to the public PubChem, FDA Substance Registration (UNII), ChEMBL and DrugBank records for the same entity.
Science
Mechanism of Action
Alpha-Klotho is a single-pass transmembrane protein expressed mainly in kidney and choroid plexus. Membrane-bound Klotho functions as an obligate co-receptor: FGF23 binds FGF receptors with low affinity alone, and Klotho is required to form a high-affinity complex, which is how FGF23 regulates phosphate excretion and vitamin D metabolism. The extracellular domain is also shed to produce soluble Klotho, which circulates and acts independently of FGF23, with reported effects on Wnt and insulin/IGF-1 signalling and on ion channel regulation. Klotho-deficient mice show a shortened lifespan with multiple ageing-like features, and overexpression extends it, which is the basis for interest in soluble Klotho in cognitive and vascular ageing. Human interventional data does not exist.
Origin
Endogenous protein; research reagents vary widely.
Targets
Studies
- Klotho gene polymorphisms are associated with healthy aging and longevity: Evidence from a meta-analysis
- Klotho antiaging protein: molecular mechanisms and therapeutic potential in diseases
- Anti-Inflammatory Role of the Klotho Protein and Relevance to Aging
- The current and emerging Klotho-enhancement strategies
- Interaction of Klotho and sirtuins
Research statistics
3,071 PubMed publications · 35.1% human clinical research · 5 registered trials
Counts of published research through 2026-11-01, not evidence that it works. Publications by year, study types and trials · How publications are counted
Regulatory & research status
Klotho is not an FDA-approved product. It is sold for laboratory research and has no approved medical use.
| FDA status | Not Approved |
|---|---|
| Availability | Research-Only |
| WADA (sport) | Unknown / Not Listed |
| Library classification | Research-Only |
How FDA approval, compounding and research-only status differ
Benefits
Klotho side effects
Klotho has no controlled human safety data. The effects below are reported, not established, and absence from the list is not evidence of safety.
Side Effects
- Unknown for unregulated vials
Storage & stability
Lyophilized (freeze-dried) peptide powder is far more stable than the reconstituted solution. Keep sealed vials cold, dry and away from light; long-term storage is typically frozen, with short-term refrigeration for vials in use.
Once reconstituted in bacteriostatic water, keep the solution refrigerated, avoid repeated freeze–thaw cycles and agitation, and label the vial with the reconstitution date and concentration. Discard any solution that turns cloudy or shows particulates.
Degradation rates differ by sequence: peptides containing methionine, cysteine, asparagine or glutamine are more prone to oxidation and deamidation, so shelf life after reconstitution is compound-specific rather than universal.
Read the full guide: how to store peptides before and after reconstitution →
Source: Manning MC, Chou DK, Murphy BM, Payne RW, Katayama DS. Stability of protein pharmaceuticals: an update. Pharm Res. 2010;27(4):544–575. (PMID 20143256). General guidance for research handling; not product-specific instructions.
Klotho: frequently asked questions
What is Klotho?
Transmembrane and soluble anti-aging protein that is an FGF23 co-receptor. Shop “Klotho” vials are not an FDA-approved drug and are often fragments or poorly characterized proteins.
How does Klotho work?
Alpha-Klotho is a single-pass transmembrane protein expressed mainly in kidney and choroid plexus. Membrane-bound Klotho functions as an obligate co-receptor: FGF23 binds FGF receptors with low affinity alone, and Klotho is required to form a high-affinity complex, which is how FGF23 regulates phosphate excretion and vitamin D metabolism.
Is Klotho FDA approved?
No. Klotho is not approved by the FDA for any indication and is categorised as research-only. It has not been reviewed for safety or efficacy as a medicine, and published research should be read as investigation rather than established use.
What peptides are similar to Klotho?
Compounds most often compared with Klotho include Epitalon, Pinealon, FOXO4-DRI and NAD+ (Nicotinamide Adenine Dinucleotide). They are grouped by shared mechanism or research area rather than by equivalence, and their regulatory status and evidence base differ.
References
- Klotho gene polymorphisms are associated with healthy aging and longevity: Evidence from a meta-analysis — Mech Ageing Dev, 2019External reference
- Klotho antiaging protein: molecular mechanisms and therapeutic potential in diseases — Mol Biomed, 2025External reference
- Anti-Inflammatory Role of the Klotho Protein and Relevance to Aging — Cells, 2024External reference
- The current and emerging Klotho-enhancement strategies — Biochem Biophys Res Commun, 2024External reference
- Interaction of Klotho and sirtuins — Exp Gerontol, 2023External reference
Related research, comparisons & guides
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Compiled by Peptide Library Editorial · Reviewed Aug 30, 2026 · Updated Nov 7, 2026 · Version 2
This Klotho profile is compiled from published literature (5 cited studies linked above), public regulatory records and chemical registries. It describes what research reports; it is not medical advice, and nothing here is a dosing recommendation for humans. Peptide Library does not sell peptides. Editorial policy · How profiles are compiled · Report an error
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