Longevity & Mitochondrial

Klotho

Also known as Klotho protein · alpha-Klotho · longevity peptide

PreliminarySubcutaneous injection (plasmid/gene-therapy delivery in early human trials)Injectable recombinant protein (animal and laboratory research)Topical and oral forms marketed in unapproved cosmetic/supplement productsNo Klotho-based product is FDA-approved as a drug for any indication; it is not an approved medicine. Klotho-derived "peptide" or protein products sold for skin, anti-aging, or general wellness are marketed as unapproved cosmetics or dietary supplements and may not lawfully carry disease treatment, prevention, or cure claims. As a large endogenous protein, Klotho is not a typical small peptide eligible for routine 503A/503B compounding, and it is not an FDA-recognized compounding bulk substance; the broader 2026 FDA peptide bulks-list reclassification activity does not establish Klotho as an approved or generally compoundable drug. Human use is otherwise confined to early-phase clinical trials (e.g., Phase 1 Klotho gene-therapy studies). For athletes, gene transfer/gene-doping technologies—the route used to raise Klotho expression—fall under the World Anti-Doping Agency (WADA) prohibition on gene and cell doping (prohibited at all times since 2003).

Klotho (alpha-Klotho) is a protein first identified in 1997, when mutations in its gene produced accelerated-aging features in mice; it exists in a membrane-bound form and a circulating "secreted" form. Mechanistically, membrane Klotho acts as a co-receptor that regulates fibroblast growth factor 23 (FGF23) signaling, phosphate handling, and vitamin D metabolism, while the secreted form has been described in laboratory and animal studies as modulating Wnt, mTOR, insulin/IGF-1, and oxidative-stress pathways. Preclinical evidence is the strongest part of the research base: studies in aged mice and aged nonhuman primates have reported improvements in cognition, and gene-therapy approaches raised Klotho levels with effects on muscle, bone, and brain measures. Human data to date is largely observational—serum Klotho levels tend to be lower with age and have been associated in cohort studies and meta-analyses with cognitive performance—together with genetic findings around the klotho-VS variant; direct interventional human studies are at an early Phase 1 stage. No Klotho-based product is approved as a medicine, and translation to safe, effective human therapy remains under investigation.

Studied / used for

Investigated for healthy aging and longevity-related biology
Studied for cognitive function and age-related cognitive decline
Investigated for kidney function and FGF23/phosphate regulation
Studied for muscle and bone health in aging models
Investigated for neuroprotection in neurodegeneration models

Commonly reported side effects

As an investigational agent, a defined human side-effect profile has not been established
Injection-site reactions commonly reported with injectable/gene-therapy delivery in early studies
Because Klotho regulates phosphate and FGF23 signaling, changes in mineral metabolism are a theoretical concern noted in research
Long-term safety in humans remains largely uncharacterized

Preliminary. Mostly early or animal studies. This reflects the strength of the research base, not effectiveness or a recommendation.

Not medical advice.

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