Klotho Peptide
The longevity protein sold as a peptide, which no trial has ever given to a person: klotho is measured in blood, not administered
Klotho is a protein the kidney makes, and its shed form circulates in blood where it acts on tissues that do not make it. It is sold online as a peptide, but no published trial has given klotho to a person: every human study measures it as a marker and watches what moves it. Exercise, in two randomised trials, did not.
What is it?
Klotho sits on the membrane of kidney cells, where it works with fibroblast growth factor 23 (FGF23) to control mineral balance. A soluble form is shed into the blood and acts as a portable co-receptor in tissues that make no klotho of their own. In chronic kidney disease, FGF23 rises while klotho expression falls, and a 2024 review describes the FGF23 excess driving heart muscle thickening, heart failure, atrial fibrillation and death, with soluble klotho possibly offsetting part of it.
That is the engine behind klotho's reputation as a longevity protein, and behind the products sold as klotho peptide. What is missing is the part where anyone gives it to a person. Across the published literature, human klotho studies measure it: in 9,976 American adults surveyed between 2007 and 2012, soluble klotho was inversely associated with metabolic syndrome, with abdominal obesity and with high triglycerides.
The randomised trials in people are trials of something else, with klotho as an outcome. Twenty-four weeks of supervised exercise in 144 young adults left plasma S-Klotho unchanged at either moderate or vigorous intensity. In 66 sedentary middle-aged adults trained for 12 weeks, S-Klotho did not track heart-rate variability at baseline, though changes in the two were associated afterwards.
So klotho is a well-studied marker of kidney and vascular health and an unstudied treatment. Nothing has been given to people, no dose exists, and no regulator has reviewed it.
At a Glance
Every value in this table is printed from the Grey Peptides dataset, the same record the compound explorer and comparison tool read, so the three can never disagree.
Published Research
These are the studies that describe klotho, read from their PubMed abstracts: a national survey, two randomised exercise trials and a review of its role in kidney and heart disease.
9,976 US adults: klotho and metabolic syndrome
In a cross-sectional analysis of a national health survey, soluble klotho concentrations were inversely associated with having metabolic syndrome and with the number of its components met, and negatively associated with abdominal obesity and high triglycerides. This is an association, not a treatment effect.
24 weeks of supervised exercise: 144 young adults
Participants were randomised to vigorous-intensity training, moderate-intensity training or no exercise. Plasma S-Klotho did not change over 24 weeks in any group, and there was no difference between them; vitamin D fell in all three.
12 weeks of training: 66 sedentary middle-aged adults
Across four groups, including high-intensity intervals with and without whole-body electrical stimulation, S-Klotho was unrelated to heart rate and heart-rate variability at baseline. After training, changes in S-Klotho were associated with changes in variability measures.
Why klotho matters in kidney disease
As kidney disease progresses, FGF23 rises while kidney klotho expression falls, and the resulting klotho-independent effects of FGF23 on the heart promote left ventricular hypertrophy, heart failure, atrial fibrillation and death. Soluble klotho may offset some of this; the authors call for randomised trials.
Side Effects & Contraindications
Reported Side Effects
No trial has given klotho to a person, so there is no side-effect record.
Contraindications & Cautions
Klotho has no label and no human dose. These cautions follow from that.
Legal Status
Klotho is a research protein with no approval anywhere.
Frequently Asked Questions
?What is klotho?
A protein made mainly by the kidney; its shed, soluble form circulates in blood and works with FGF23 to control mineral balance.
?Has klotho been given to people?
No published trial has. Human studies measure klotho in blood, and the randomised trials test exercise or other treatments with klotho as an outcome.
?Does exercise raise klotho?
Not in the trials here: 24 weeks of supervised training in 144 young adults left S-Klotho unchanged at either intensity.
?Is there a klotho dose?
No. Nothing has been given to people, so no dose exists.
References
- [fda] FDA. Drugs@FDA (openFDA): no application for klotho. Read September 30, 2026.
- [pubmed] Cheng YW, et al. "Association between Soluble α-Klotho Protein and Metabolic Syndrome in the Adult Population." Biomolecules, 2022;12(1). PMID: 35053218.
- [pubmed] Amaro-Gahete FJ, et al. "Impact of 24-week supervised concurrent exercise on S-Klotho and vitamin D levels: A randomized controlled trial." J Sports Sci, 2024;42(24):2562-2571. PMID: 39831661.
- [pubmed] Navarro-Lomas G, et al. "Exercise-induced changes in plasma S-Klotho levels are associated with the obtained enhancements of heart rate variability in sedentary middle-aged adults: the FIT-AGEING study." J Physiol Biochem, 2024;80(2):317-328. PMID: 38175501.
- [pubmed] Edmonston D, et al. "FGF23 and klotho at the intersection of kidney and cardiovascular disease." Nat Rev Cardiol, 2024;21(1):11-24. PMID: 37443358.
- [pubmed] Kurosu H, et al. "Suppression of aging in mice by the hormone Klotho." Science, 2005;309(5742):1829-33. PMID: 16123266.
- [pubmed] Castner SA, et al. "Longevity factor klotho enhances cognition in aged nonhuman primates." Nat Aging, 2023;3(8):931-937. PMID: 37400721.
Sources & Citations
Every study on this page was read from its PubMed record. Regulatory status comes from FDA's Drugs@FDA database (openFDA), read September 30, 2026.
Medical Disclaimer: This content is for educational and informational purposes only. It is not medical advice, and nothing here is an instruction to obtain or use any compound. Consult a licensed healthcare provider before making health decisions.