Klotho
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
- Administration Route
- Research only
- Frequency
- —
- Last updated
- Aug 30, 2026
- Reviewed
- Aug 30, 2026
- Targets
- FGFR/FGF23Aging-related pathways
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.
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.
Protocol
- Dosage Range
- Not established as a drug
- Frequency
- —
- Cycle
- —
- Administration Route
- Research only
- Reconstitution Guide
- —
- 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
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 |
Benefits
Potential Side Effects
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 Aug 30, 2026 · Version 1
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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