Longevity / Published Sep 8, 2026 / Reviewed Sep 27, 2026 / 8 min read
Klotho Explained: Protein, Peptide, Gene Therapy or Supplement?
Written by Aaron CuhaReviewed Sep 27, 2026
What klotho is, what is known in people so far, what the mouse and monkey studies showed, the two human programs that started in 2026, and why the 'klotho peptide' sold online is not the molecule in any of those studies. Plain English, every study linked.
Key takeaways
- Klotho is a large protein, roughly 130 kDa, made mostly in the kidney and brain. Part of it breaks off and travels in the blood (called s-KL). That level falls with age.
- In people, we only have links, not proof. People with less klotho in their blood tend to think less sharply and die sooner. People born with a gene version that gives them a bit more klotho tend to think better. Nobody has shown that raising klotho in an adult changes anything.
- No klotho drug is approved. Two programs in people began in 2026. Klothea Bio is running a 21-person safety study of AKL003, a klotho made by the body from an mRNA shot. Klotho Neurosciences is preparing a gene therapy (KLTO-202) for ALS.
- In animals, the evidence is strong. Mice missing klotho age fast. Mice with extra klotho live longer. One low dose improved memory in old monkeys (Nature Aging, 2023). A 2025 gene therapy study made male mice live 19.7% longer.
- Products sold as 'klotho peptide' or 'alphaKlothoLR' are short pieces or unrelated peptides. A 20 microgram vial can't come close to the doses used in the animal work, and nobody has tested them in people.
What is klotho and can you buy it?
Direct answer
Klotho is a protein linked to aging, made mostly in the kidney and brain. The part that travels in the blood, s-KL, falls as you get older. No klotho drug is approved. A 21-person safety study in people began in 2026. In mice, one gene therapy dose in 2025 added 19.7% to lifespan. Products sold as 'klotho peptide' are lab chemicals or different peptides.
The name comes from the Greek Fate who spins the thread of life, and it earned it. In 1997, a team led by Makoto Kuro-o found that mice with a broken klotho gene got hard arteries, thin bones, thin skin, could not breed and died young, much like fast human aging (Nature, 1997). In 2005 the same group showed the reverse. Mice with extra klotho lived roughly 20 to 30 percent longer (Science, 2005). Few genes have evidence pointing both ways like that, which is why klotho gets so much talk in longevity circles.
What klotho does in the body
Klotho sits on kidney cells and helps a hormone called FGF23 control phosphate and vitamin D. Part of it breaks off into the blood and the fluid around the brain. That loose form, s-KL, works like a hormone. It turns down insulin and growth signals, calms another growth signal called Wnt, helps the body's own defenses against cell damage and helps brain cells talk to each other. A close cousin, beta-klotho, works with a hormone called FGF21. That is why klotho keeps coming up alongside drugs like efruxifermin.
What is known in people
In people, klotho levels are highest in early adulthood and then drop steadily. Lower levels go along with long-term kidney disease, heart attacks and strokes, frailty and worse thinking. Some people carry a gene version called KL-VS that gives them a bit more klotho. In several studies that followed groups of people, carriers thought more sharply and their brains aged differently. In people with a high genetic risk of Alzheimer's, carriers had less of the plaque linked to it (Neurobiology of Aging, 2021). These are links, not proof. None of them shows that raising klotho in an adult changes what happens to them.
What the animal studies showed
| Study | Who or what | What was done | What happened | Type of evidence |
|---|---|---|---|---|
| KL-VS gene studies | People | Nothing given; compared people born with the gene version | Carriers thought more sharply | Links in people, not proof |
| Castner, Nature Aging 2023 | Old rhesus monkeys | One small klotho shot under the skin | Better short-term memory for weeks | Animal (monkey) |
| Molecular Therapy 2025 | Adult mice | One gene therapy dose that makes loose klotho, given at 6 or 12 months of age | Males lived 19.7% longer; bone, muscle and brain measures got better | Animal |
| Kurosu, Science 2005 | Mice | Extra klotho | Lived 19 to 31 percent longer | Animal |
| Dubal, Cell Reports 2014 | Mice | More klotho | Better thinking, more of a memory-related protein called GluN2B | Animal |
| Kuro-o, Nature 1997 | Mice | Klotho gene broken | Aged early, died young | Animal |
The 2023 monkey paper is what moved klotho from a mouse curiosity to something worth trying in people. Old rhesus monkeys got one shot of klotho at 10 micrograms per kilogram. They did better on a memory task, and it lasted about two weeks (Nature Aging, 2023). Higher doses did not work better, which is common with hormones. The 2025 gene therapy study (Molecular Therapy) is the first to show longer life from a treatment given to animals that were already adults.
When will klotho gene therapy be available?
Direct answer
No klotho treatment is approved or in big late-stage studies. As of September 2026, Klothea Bio started a 21-adult safety study of AKL003, an mRNA klotho given into a vein, in Honduras in February 2026. Klotho Neurosciences plans to ask the FDA to start testing KLTO-202, a gene therapy for ALS, around late 2026 to early 2027. Minicircle sells an unregulated klotho gene therapy offshore. Any approval is years away.
- AKL003 (Klothea Bio): an mRNA that makes the body produce klotho for a while. The early study signed up 21 adults at a clinic in Roatan and looks at safety first (Longevity.Technology, 2026). No results on whether it works have been reported.
- KLTO-202 (Klotho Neurosciences): a gene therapy that makes loose klotho, aimed at ALS. It has special status for rare diseases. It has not been tested in people.
- Minicircle: sells a klotho gene therapy outside any regulator. No results have been published.
What is the 'klotho peptide' sold online?
Direct answer
Real klotho is a big protein, 998 building blocks long and about 130 kilodaltons. Vials sold as 'klotho peptide' or 'alphaKlothoLR', often around $500 for 20 micrograms, are short lab-made pieces or research chemicals. One is 'klotho-derived peptide 1', a kidney research tool. None has been studied in people. A 20 microgram vial could not give an adult the 10 micrograms per kilogram used in the monkey study.
Our Klotho profile keeps a running list of what is sold under the name. The short version: nothing you can buy is the molecule from the studies above.
Do klotho supplements work? What raises klotho in humans?
Direct answer
No supplement contains klotho. In people, higher klotho in the blood goes along with regular cardio exercise, enough vitamin D, healthy kidneys and, in some groups, common blood pressure and diabetes drugs. These links come from watching people or from small studies. None has shown that raising klotho makes people healthier.
A small kidney study in people found that the senolytic pair dasatinib plus quercetin raised klotho. It did the same in mice. That is where the Reddit claim that 'senolytics restore klotho' comes from. It is a hint about how things work, not a treatment.
The bottom line
Klotho is one of the best-backed aging targets in animals, and no finished study has tested whether it works in people. That mix draws both serious biotech money and gray-market products with the same name. If you see klotho on a vial, ask three things. Is this the full protein? What dose? Where are the results in people? In 2026 the honest answers are no, too small and nowhere yet.
Frequently asked questions
What does the klotho peptide do?
Nobody has published whether the products sold under that name do anything, in people or animals. The klotho research is about the full 130 kDa protein, or gene therapies that make the body produce it.
How can I increase my klotho levels?
Studies that watch people link higher klotho to cardio exercise, enough vitamin D and healthy kidneys. Nothing has been proven to improve health by raising klotho.
Is there a klotho supplement?
No. Klotho is a big protein that your gut would digest if you swallowed it, and no supplement contains it. Products sold as klotho boosters rely on indirect ideas nobody has proven.
What foods increase klotho?
No food has been shown to raise klotho in a proper study in people. Studies of diet quality only show links.
Compound profiles mentioned
- KlothoPreliminary. Studied in people, but no published study has had people take it. 2 human studies where nobody was given it.Longevity
- EfruxiferminModerate. At least one finished study in people, and at least 100 people who took it. 1 completed trial, 181 people given it.Metabolic
- DasatinibLimited. People have taken it in a published study, but fewer than 100 of them. 3 completed trials, 74 people given it.Longevity
- QuercetinLimited. People have taken it in a published study, but fewer than 100 of them. 3 completed trials, 60 people given it.Longevity
- ER-100Preliminary. Studied in people, but no published study has had people take it. 2 human studies where nobody was given it.Longevity
- FOXO4-DRILimited. People have taken it in a published study, but fewer than 100 of them. 1 completed trial, 74 people given it.Anti-aging
Sources
- Study in people2021
KL-VS heterozygosity reduces brain amyloid in asymptomatic at-risk APOE4 carriers
People at high genetic risk of Alzheimer's who carry the KL-VS klotho gene version had less of the brain plaque linked to it.
Neurobiology of Aging - Study in people2026
Klothea initiates longevity-focused human trial of klotho therapy
A 21-person early safety study of AKL003.
Longevity.Technology - Animal study2023
Longevity factor klotho enhances cognition in aged nonhuman primates
In old monkeys, one small dose improved memory.
Nature Aging - Animal study2025
Single-dose AAV secreted-klotho gene therapy extends lifespan in adult mice
In mice, males lived 19.7 percent longer.
Molecular Therapy - Animal study2005
Suppression of aging in mice by the hormone Klotho
In mice, extra klotho made them live longer.
Science - Animal study2014
Life extension factor klotho enhances cognition
In mice, more klotho meant better thinking.
Cell Reports - Animal study1997
Mutation of the mouse klotho gene leads to a syndrome resembling ageing
In mice, losing klotho made them age fast.
Nature - Review of studies2019
The Klotho proteins in health and disease
A full review of what klotho does in the body.
Nature Reviews Nephrology
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