Biohacking Kompakt

Peptide & experimental

Klotho

Endogenous protein and circulating hormone, longevity candidate without approval · alpha-Klotho, sKlotho, soluble Klotho, KL

Klotho is an endogenous hormone that circulates in the blood. If a mouse lacks it, the animal ages at breakneck speed; if the gene is turned up, it lives longer. In humans there are gene variants, blood levels and a monkey experiment on this, but no medicine.

In short

Klotho is a protein of more than 1,000 amino acids that is formed mainly in the kidney, circulates in the blood and dampens insulin and IGF-1 signals. In mice with an overexpressed gene it extends lifespan by 19 to just over 30 percent — however, the gene was turned up from conception, which is not a treatment but a different animal. In humans the data contradict each other: a gene variant is associated with better cognition in one study, with worse outcomes in a Danish and a Scottish cohort, and low Klotho levels in the blood are linked to higher mortality, without this establishing a cause. The first blinded, placebo-controlled study in humans has been running in Honduras since February 2026; results are pending.

What Klotho is

The name comes from the goddess of fate who spins the thread of life. In 1997, a Japanese group led by Makoto Kuro-o described in Nature a gene that had been accidentally destroyed in mice. The animals aged at breakneck speed: arterial calcification, osteoporosis, emphysema, short lifespan. A single defective gene produced an aging syndrome.

Klotho is a protein of more than 1,000 amino acids, part of which circulates in the blood as a hormone. It is formed mainly in the kidney — this place of origin becomes important later.

How it is supposed to work

Klotho dampens insulin and IGF-1 signals. This pathway has played a leading role in aging research for decades, because dampening it is associated with longer lifespan in several animal species.

In 2005 the counter-test came in Science: Klotho overexpressed, two independent mouse lines, both lived longer. In males 20 percent in one line and just over 30 percent in the other, in females around 19 percent. Exactly this range appears today on practically every sales page. What is not stated there: the gene was turned up from conception. Only in 2025 did a group from Barcelona give Klotho by gene therapy to normally aging adult mice: the males lived 31.5 instead of 26.3 months on average, almost 20 percent longer; the authors themselves discarded the data on the females because of frequent skin diseases.

What was measured in humans

In 2014, a group led by Dena Dubal showed in Cell Reports, in 718 people from three cohorts, that carriers of one copy of the gene variant KL-VS perform better in cognitive tests. The catch is in the same paper: about 3 percent carry two copies, and in them the advantage is not just gone — two copies are linked to a shorter lifespan. The authors excluded this group and write that the reason is unknown.

The follow-up checks do not make things clearer. In a Scottish birth cohort, carriers had shorter survival; in a Danish study of 1,480 very old people, they fared worse. Both groups suspect an age-dependent effect. In the German Heinz Nixdorf Recall Study with 1,812 adults, carriers scored slightly lower in all tests. Above all, this means: the cognition finding is not robust.

Another finding has held up: in carriers of the risk variant APOE4 aged 60 and over, one copy of KL-VS was associated with a quarter lower risk of Alzheimer’s disease (JAMA Neurology 2020).

The blood level

The second line of evidence is the concentration in the blood. In the Italian InCHIANTI cohort, data from 804 people aged 65 and over were analyzed over 6 years in 2011. The lowest third of Klotho levels had a risk of death about 78 percent higher than the highest third.

That is a strong association and still not a cause. Klotho in the blood comes mainly from the kidney, and people who are ill have lower levels. The level may therefore indicate the disease rather than cause it.

More is not automatically better. A US analysis (NHANES 2007–2016) found a U-shaped relationship: the lowest fifth had a risk of death about 37 percent higher, but the highest fifth also had one about 21 percent higher than the middle.

Your own level can be shifted: two 2026 meta-analyses find marked increases after endurance training and especially after strength training. The authors emphasize high risks of bias and that the blood level indicates a response but is not a validated treatment target.

The monkey experiment

The most cited paper is from 2023 in Nature Aging, again from Dubal’s group. It studied 18 rhesus monkeys aged 15 to 28 years, which on average corresponds roughly to a 65-year-old human. The animals received a single injection under the skin, at three dose levels. At the lowest, the memory effect lasted at least 2 weeks.

The most interesting part is the uncomfortable one: the two higher levels did not work. A dose curve without an upward trend is an argument against one’s own work, and the authors report it anyway. Anyone wanting to dress up results does not do it this way. Funding came from government health institutes and Unity Biotechnology.

What is being sold

Capsules called Klotho boosters contain no Klotho. They could not: a protein of more than 1,000 amino acids is broken down in the digestive tract. What is sold are substances that are supposed to raise the blood level. Whether anyone lives longer as a result has not been tested.

The second form of offering is the clinic. In Roatán, Honduras, 2 pilot studies with Klotho as plasmid gene therapy are registered, 14 people each, single-arm, without placebo and without blinding; one of them, with Klotho plus follistatin, has been completed since April 2026, and no results are posted in the registry. Since February 2026, the first blinded, placebo-controlled study with 21 participants has also been running there.

What is well supported

The biology in animals is robust. Loss of the gene produces an aging syndrome in mice, overexpression extends lifespan — two independent lines, both sexes, Nature and Science. The pathway behind it, the dampening of insulin and IGF-1 signals, is not an invention of the longevity industry. What has been properly measured in humans is the association between low Klotho levels and higher mortality in old age.

What the studies show

Kuro-o et al., Nature 1997 — the loss

Mice in which a gene had been accidentally destroyed developed arterial calcification, osteoporosis and emphysema and died early. The gene was named Klotho.

Science 2005 — the counter-test

Klotho overexpressed in two independent mouse lines, both lived longer than their controls: males 20 and just over 30 percent, females around 19 percent. The design is decisive — the gene was turned up from conception, not a treatment of adult animals.

Roig-Soriano et al., Mol Ther 2025 — treatment of adult mice

Normally aging wild-type mice received secreted Klotho by gene therapy. The males lived 31.5 instead of 26.3 months on average, an increase of 19.7 percent. The authors themselves discarded the data on the females because of frequent skin diseases.

Dubal et al., Cell Reports 2014 — the gene variant

Observational study in 718 people from three cohorts on the KL-VS variant. Carriers of one copy performed better in cognitive tests. Carriers of two copies, about 3 percent, did not have the advantage and were excluded. A Scottish birth cohort and a Danish study of 1,480 very old people found worse outcomes for carriers.

InCHIANTI, Tuscany 2011 — the blood level

Observational study in 804 people aged 65 and over over 6 years. The lowest third of Klotho levels had a risk of death about 78 percent higher than the highest third. Association, not cause: Klotho in the blood comes mainly from the kidney, and illness lowers the level.

Dubal et al., Nature Aging 2023 — the monkeys

Animal experiment in 18 rhesus monkeys aged 15 to 28 years, on average roughly a 65-year-old human. A single injection under the skin at three dose levels; at the lowest, the memory effect lasted at least 2 weeks, the two higher levels showed no effect.

Where the data stop

The gap is easy to name: to this day there are no results from a regular study with Klotho as a medicine; the first blinded, placebo-controlled study has been running since February 2026. Everything available is observation — a gene variant that one does not choose, and a blood level that no one has deliberately changed. In addition, the genetics contradict each other: one copy of KL-VS positive, two copies negative, carriers worse overall in both the Scottish and the Danish follow-up. An age-dependent effect would be a possible explanation; it has not been proven.

Status, approval and legal

There is no approved Klotho product, neither in Germany nor in the EU nor in the US, and therefore no legal way to obtain it. The first blinded, placebo-controlled study in humans has been running in Honduras since February 2026, with 21 participants; primary completion is planned for November 30, 2026. The successor company of the monkey work, Jocasta Neuroscience, raised 35 million US dollars in August 2025 and expanded its license from the University of California San Francisco in August 2026; it plans to submit the application for a first human study in the fourth quarter of 2026, with a start in early 2027. Outside any approval, Klotho is used in Roatán, Honduras, as plasmid gene therapy in 2 pilot studies with 14 people each. Klotho boosters sold as food supplements contain no Klotho; they are subject to food law and may not carry healing claims.

Safety

Almost nothing is known about safety in humans, because there has been almost no use. There are no controlled tolerability data, no long-term follow-up, no systematic recording of side effects. From the monkey experiment there is a single dose over 2 weeks, which says nothing about repeated use. The gene therapy variant in Honduras additionally brings all the questions of plasmid administration, without published results. Missing data are not an indication of harmlessness but of missing research.

BK-Score Hype far ahead of evidence

Human evidence2
Mechanism5
Safety data1
Hype gap2
Track record of use2

evidence 2: in humans there is no interventional study with results — everything is observation (718 people on the gene variant KL-VS in 2014, 804 people in InCHIANTI in 2011), and the genetics contradict each other between the Scottish, the Danish and the US analysis. mechanism 5: the pathway via insulin and IGF-1 dampening is documented in mice and monkeys and at least hinted at in humans through the gene variant and blood level, but never tested in humans. safety 1: there has been almost no use, and accordingly no systematically collected tolerability data; the monkey experiment provides a single dose with 2 weeks of observation. hype 2: the 20 to 30 percent life extension is stated everywhere, the condition — the gene was turned up from conception — nowhere, and capsules are sold as Klotho boosters even though a protein of more than 1,000 amino acids is digested. use 2: Klotho is used only in studies and on the gray market, for example in 2 pilot studies with 14 people each in Honduras; since February 2026, the first blinded, placebo-controlled study with 21 participants has also been running there, and results are pending.

The score rates the state of knowledge, not the substance. “Safety data 9” means well studied – not harmless.
Subjective assessment by Biohacking Kompakt based on published scoring rules – not a scientific rating and not a medical recommendation. Rules and all ratings (German)

Frequently asked questions about Klotho

Does Klotho extend life in humans?

That has not been studied. The life extension of 19 to just over 30 percent comes from mice in which the gene was turned up from conception. In humans there are only observational data on gene variants and blood levels, and these partly contradict each other.

Why are Klotho capsules useless?

Klotho is a protein of more than 1,000 amino acids. A protein of this size is broken down in the digestive tract and does not reach the blood intact. Klotho boosters sold as capsules therefore contain no Klotho, but substances that are supposed to raise the body’s own level. Whether this benefits anyone has not been tested.

What does a low Klotho blood level mean?

In the InCHIANTI cohort, the lowest third of levels had a risk of death about 78 percent higher than the highest third. That is an association and not a cause. Klotho in the blood comes mainly from the kidney, and people who are ill have lower levels — the level may therefore indicate the disease rather than produce it.

Is the gene variant KL-VS good or bad?

Both have been reported. In the 2014 study of 718 people, carriers of one copy performed better in cognitive tests, carriers of two copies did not. In a Scottish birth cohort and in a Danish study of 1,480 very old people, carriers had worse outcomes. The literature is not consistent on this point.

Can I get Klotho anywhere?

It is not approved anywhere. It is offered outside any approval, for example in Honduras as plasmid gene therapy in two pilot studies without placebo and without published results. Since February 2026, a blinded, placebo-controlled study has also been running there; the successor company of the monkey work plans to start its first human study in early 2027.

Why did the higher doses not work in the monkey experiment?

That is open. The 2023 paper found a memory effect only at the lowest of three dose levels tested, none at the two higher ones. A dose curve without an upward trend weakens the claim that there is a genuine drug effect here. That the authors report it anyway, however, speaks for the integrity of the work.

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Sources

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Information only, not medical advice and not a usage or dosage recommendation. Prescription-only and unapproved substances belong in the hands of a physician. Last updated: 2026-09-19.