Klotho
An endogenous anti-aging protein and FGF23 co-receptor whose circulating levels track healthy aging, cognition, and cardiovascular longevity.
Klotho is a transmembrane protein and circulating hormone encoded by the KL gene, expressed mainly in kidney distal tubules and brain choroid plexus, that acts as a co-receptor for fibroblast growth factor 23 (FGF23) and as a systemic longevity regulator. Circulating alpha-klotho declines with age and lower levels are associated with cognitive decline, accelerated aging phenotypes, and increased cardiovascular mortality. Mouse models overexpressing klotho live roughly 30% longer, while klotho-deficient mice develop premature aging syndromes. Exogenous klotho has no FDA approval and no published human interventional trial data, so it remains an active research target rather than an established therapeutic.
Class
Endogenous transmembrane protein and circulating hormone (KL gene product)
Routes
Subcutaneous, Intravenous
Category
Longevity & Bioregulators
Researched benefits
What it's studied for
Neuroprotection and cognitive support
Higher circulating klotho is associated with better cognitive performance and lower dementia incidence in human cohort and meta-analytic data. A systematic review and meta-analysis of 6,645 participants found a significant positive correlation between klotho levels and cognitive function, supporting it as a biomarker of cognitive aging.
Cardiovascular protection
Large human cohort data associate higher circulating alpha-klotho levels with reduced cardiovascular mortality, positioning klotho as a marker of cardiovascular longevity.
Anti-aging and longevity regulation
Mouse models overexpressing klotho live approximately 30% longer, while klotho-deficient mice develop premature aging syndromes, establishing klotho as a key mammalian longevity regulator. Its deficiency specifically disrupts mitochondrial and metabolic transcriptomic programs in cross-species aging analyses.
Mineral and phosphate homeostasis
As a co-receptor for FGF23, klotho regulates phosphate and vitamin D metabolism and calcium-phosphate homeostasis, functions relevant to renal aging and vascular calcification.
Anti-fibrotic and antioxidant activity
Soluble klotho suppresses TGF-beta fibrotic signaling and activates Nrf2 antioxidant pathways while reducing oxidative stress and inflammation, mechanisms linked to tissue protection in preclinical models.
Renal aging biomarker
Klotho expression progressively declines with kidney aging and correlates with kidney damage markers, making it a recognized marker of renal age-related change in preclinical work.
Mechanism
How it works
Klotho functions as an obligate co-receptor for fibroblast growth factor 23 (FGF23), enabling FGF23 signaling that regulates phosphate excretion and vitamin D metabolism. Through this axis klotho maintains calcium-phosphate homeostasis, a role central to its effects on renal aging and vascular calcification.
As a circulating hormone, soluble klotho exerts pleiotropic protective effects independent of FGF23. It inhibits insulin/IGF-1 signaling — a conserved longevity mechanism — and suppresses Wnt signaling, both of which are associated with lifespan extension in animal models.
Klotho activates Nrf2-driven antioxidant defenses and reduces oxidative stress and inflammation, while suppressing TGF-beta fibrotic signaling. These combined actions underlie its anti-fibrotic and tissue-protective properties.
In the brain, klotho provides neuroprotective effects relevant to brain aging. Higher circulating levels track with better cognitive performance and lower dementia incidence in human data, though the precise neural mechanisms and whether exogenous klotho reproduces these effects in humans remain under investigation.
Evidence
Research & clinical studies (10)
Klotho heterozygosity does not modify cognitive decline in APOE epsilon4 carriers: analysis of a large biobank cohort
In 320,861 participants, APOE epsilon4 homozygotes showed greater cognitive decline than heterozygotes, and klotho heterozygosity did not independently modify cognitive trajectories after controlling for APOE genotype.
PMID 39903109Klotho protein and cognitive function: a systematic review and meta-analysis
Across studies totaling 6,645 participants, higher klotho levels significantly correlated with better cognitive function, with subgroup analyses confirming significance for serum and plasma alpha-klotho.
PMID 40048920Universal transcriptomic hallmarks of mammalian ageing and mortality
Integrating over 11,000 transcriptomes across four mammalian species, klotho deficiency specifically disrupted mitochondrial and metabolic transcriptomic modules, a pattern distinct from caloric restriction.
PMID 42203874VSIG4 Expression During Renal Aging Is Accelerated by Type 2 Diabetes in Mice
Klotho expression declined progressively with kidney aging while urinary VSIG4 rose and correlated with kidney damage markers, with the process accelerated in type 2 diabetic mice.
PMID 42195288The association between exposure to flame retardants and cognitive function in the elderly: Unveiling potential intervention strategies
Serum klotho was statistically associated with both flame retardant exposure and cognitive outcomes in the elderly, suggesting klotho may mediate the exposure-cognition relationship.
PMID 42214759Gene deletion of Klotho in the dentate gyrus does not affect the number of adult-born granule cells
Deleting klotho specifically in the dentate gyrus did not alter the production or number of newly generated neurons in adult mice, indicating it is not required for normal adult neurogenesis there.
PMID 42204218Conserved mRNA expression patterns of the Klotho family in canine mammary tumors and human breast cancer
Klotho family members showed conserved tumor expression patterns across species, with alpha- and beta-klotho reduced and gamma-klotho overexpressed, particularly in more aggressive cases.
PMID 42218196Vitamin D attenuates Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) and downregulates hepatic gluconeogenesis in obesity
Vitamin D attenuated MASLD and downregulated hepatic gluconeogenesis in obesity, within a klotho-related metabolic context.
PMID 42323099Podocyte mPGES-2 Determines Renal Aging and Contributes to Senile Osteoporosis
Podocyte mPGES-2 was shown to drive renal aging and contribute to senile osteoporosis, part of the renal-aging axis in which klotho is a marker.
PMID 42347750Association between soluble Klotho levels and calcification propensity T50 in patients with hemodialysis: a cross-sectional study
A cross-sectional study of hemodialysis patients examined the relationship between soluble klotho levels and serum calcification propensity (T50).
PMID 42332137Safety
Side effects & considerations
Contraindications & cautions
- Kidney or liver condition
- Pregnant or nursing
Klotho carries a moderate risk profile in research contexts. Because there is no published human interventional data, its safety as an administered agent in humans is not established. Review contraindications and consult a qualified healthcare professional before any use.
FAQ
Klotho — common questions
What is Klotho?
Klotho is an endogenous transmembrane protein and circulating hormone encoded by the KL gene, expressed primarily in kidney distal tubules and brain choroid plexus. It acts as a co-receptor for FGF23 and as a systemic anti-aging regulatory factor. Circulating alpha-klotho declines with age and lower levels are associated with cognitive decline, accelerated aging phenotypes, and increased cardiovascular mortality.
What is Klotho primarily studied for?
Neuroprotection, cardiovascular protection, anti-aging, cognitive support, and anti-fibrotic effects.
What does the research show about Klotho?
Human cohort and meta-analytic data associate higher circulating klotho with better cognition and lower cardiovascular mortality, and mouse models overexpressing klotho live about 30% longer. However, exogenous klotho has no human interventional trial data, so its promise as an administered therapy remains preclinical.
Is there a standard dose for Klotho?
No. There is no established human dosing protocol, no published human interventional trials, and no verified providers currently listing the compound. Preclinical anti-aging effects have only been observed with recombinant klotho in animal models.
Is Klotho FDA approved?
No. Klotho has not been evaluated or approved by the FDA and is classified as research-only.
What are the side effects and contraindications of Klotho?
Klotho carries a moderate risk profile. Reported contraindications and considerations include kidney or liver conditions and pregnancy or nursing. Because human safety data are absent, consult a qualified healthcare professional before use.
Why does Klotho matter for longevity?
Klotho is a robust human biomarker of healthy aging: mice overexpressing it live roughly 30% longer while klotho-deficient mice age prematurely, and in humans higher levels track with better cognitive performance, lower dementia incidence, and reduced cardiovascular mortality.
