Klotho is a single-pass transmembrane protein whose name comes from the Greek goddess who spins the thread of life. Discovery came from a 1997 Nature paper showing that mice deficient in the klotho gene develop a syndrome closely resembling accelerated human aging - shortened lifespan, vascular calcification, osteoporosis, cognitive decline. Klotho overexpression extends mouse lifespan by 20-30%. In humans, higher circulating Klotho correlates with longer lifespan and better cognitive performance in multiple cohort studies. The compound is in early-stage exogenous-administration research; there is no standardized human protocol yet.
Research notes
What Klotho is
Klotho is a single-pass transmembrane protein with two key features that drive longevity-research interest. The extracellular domain can be cleaved by ADAM10/17 to produce soluble Klotho, which circulates as a hormone with effects on phosphate / vitamin D homeostasis, IGF-1 signaling suppression, Wnt pathway suppression, and oxidative-stress resistance. The membrane-bound form acts as a co-receptor for FGF23 in kidney phosphate regulation.
The gene was discovered in 1997 when mice with a homozygous klotho mutation developed a syndrome closely resembling accelerated human aging — premature death, vascular calcification, osteoporosis, cognitive decline, skin atrophy. The phenotype was striking enough that the gene was named after the Greek goddess Klotho who spins the thread of life.
Why the evidence base is unusually strong for an early-stage longevity target
Most longevity-research compounds have one or two lines of supporting evidence. Klotho has three that converge.
Mouse lifespan extension. Klotho overexpression in transgenic mice extends lifespan 20-30% in both sexes, replicated across multiple labs. The effect is dose-dependent.
Knockout phenotype. Klotho-deficient mice develop a syndrome that meets the formal criteria for accelerated aging — multiple aging-related pathologies, shortened lifespan, cellular senescence markers, and reduced healthspan endpoints across organ systems.
Human cohort correlation. Higher serum Klotho levels correlate with longer lifespan, better cognitive performance, and reduced cardiovascular mortality across multiple cohort studies including InCHIANTI and others. The correlation is consistent enough that Klotho has been proposed as a longevity biomarker.
The gap is the delivery mechanism — there is no FDA-approved Klotho drug, and the full-length protein is large enough that conventional injection routes have low bioavailability.
What this means for buyers
Klotho is at an earlier research stage than rapamycin, NAD+, or the GH-axis peptides. There is no standardized human dosing protocol. Short Klotho-mimetic peptide fragments circulate in the research-peptide market but should be approached skeptically — they are typically not full-length Klotho. Authentic recombinant Klotho protein is generally only available from research-supply houses rather than the research-peptide vendor pool.
A buyer looking for an immediately-administrable Klotho intervention does not yet have one. A buyer interested in tracking Klotho as a biomarker can request a serum Klotho test through a longevity-medicine practitioner.
Related reading
- Rapamycin peptide page — currently the most-deliverable longevity intervention with mouse-replicated lifespan data.
- NAD+ peptide page — the other major aging-mechanism target with clinical-research interest.
- Epitalon peptide page — earlier-stage longevity peptide with a different evidence base.
- Longevity peptides 2026 overview — where Klotho sits in the broader longevity-compound landscape.
What it's researched for
- longevity research
- cognitive / neuroprotective research
- kidney function research
Where to source it
ALL 0 VENDORS →No vendors in our audit cycle currently list Klotho as a specialty. Cross-reference the leaderboard for vendors that may stock it on request.
Frequently asked about Klotho
What is Klotho?
Klotho is a single-pass transmembrane protein, named after the Greek goddess Klotho who spins the thread of life. It was discovered in 1997 when researchers found that mice with a klotho gene mutation developed a syndrome closely resembling accelerated human aging. The extracellular domain is cleaved to produce soluble Klotho (sKlotho), which acts as a circulating hormone.
Why is Klotho studied for longevity?
Three converging lines of evidence. First, klotho-deficient mice develop accelerated aging; klotho-overexpressing mice live 20-30% longer. Second, soluble Klotho directly suppresses IGF-1 signaling and Wnt pathway activity, both implicated in aging. Third, human cohort studies consistently show higher Klotho levels correlate with longer lifespan and better cognitive performance. The mouse-to-human translation is the active research question.
Can Klotho be administered as a drug?
Not yet in standardized human protocols. The protein is large (over 100 kDa for the full molecule), which makes subcutaneous and oral bioavailability a research-protocol challenge. Mouse studies use intraperitoneal recombinant Klotho injection. Several biotech companies are working on Klotho-elevating small molecules or shorter peptide fragments that could be administered orally; none have yet reached late-stage human trials.
How does Klotho compare to other longevity interventions?
Klotho has a stronger mechanistic case than most. The mouse lifespan-extension data is robust (20-30% extension), the gene-knockout phenotype is dramatic (accelerated aging syndrome), and the human cohort correlations are consistent. What it lacks is a delivered drug. Compare with rapamycin, which has both the model-organism lifespan data and a deliverable drug — Klotho has the biology but not yet the deliverable compound.
What's the current research-protocol use?
Today Klotho is primarily a biomarker rather than an administered intervention. Serum Klotho levels are measured to assess kidney function and as a potential aging biomarker. Exogenous administration is in preclinical research using recombinant Klotho protein at 10-50 mcg/kg in mouse studies. Human dosing protocols do not yet exist in standardized form.
Is Klotho available through research-peptide vendors?
Klotho fragments and short peptides claimed to be Klotho-mimetics circulate in the research-peptide market. The full-length Klotho protein is large and complex enough that authentic recombinant material is typically only available from research-supply houses (Sigma-Aldrich, R&D Systems, Abcam) rather than the research-peptide vendor channel. Buyers should be skeptical of "Klotho peptide" listings in standard peptide-vendor catalogs - those are usually shorter unrelated peptide fragments using the brand name loosely.