What it is
Klotho is not a peptide. It is a large protein made of 1,012 amino acids with sugar chains attached. It weighs about 130,000 daltons, which is far bigger than a typical research peptide. Klotho sits in cell membranes, mostly in the kidney. There it works with the hormone FGF23 to control phosphate and vitamin D. Part of the protein breaks off and travels in the blood, where it acts like a hormone. This part is called soluble klotho. Klotho has to be made in mammal cells. It cannot be made the way small peptides are made. Because of this, a vial sold as a "klotho peptide" cannot be confirmed to contain real klotho. Other names: Alpha-Klotho, KL, Soluble Klotho.
What researchers study it for
- Aging in mice
- Memory and learning in mice and monkeys
- Phosphate and vitamin D control
- Blood levels and death risk in older adults
- Kidney disease
What the studies found
1. Mice without klotho aged fast.
This 1997 study found a mouse line with a broken klotho gene. The mice had short lives, hardened arteries, weak bones, thin skin, and lung damage. These are changes that look like fast aging. This study named klotho as an aging-suppressor gene. Animal data.
2. Mice with extra klotho lived 20 to 30 percent longer.
This 2005 study bred mice that made extra klotho. They lived 20 to 30 percent longer than normal mice. Klotho lowered insulin and IGF-1 signaling, a pathway tied to lifespan in worms and flies. The mice also resisted oxidative stress better. Animal data.
3. Older adults with low klotho had a higher death risk.
This 2011 study measured klotho in the blood of 804 adults aged 65 and older in Italy. They were followed for 6 years. People in the lowest third of klotho levels had a 78 percent higher death risk than those in the highest third. This held after adjusting for age and disease. It shows a link, not a cause. Human observational data.
4. People with a gene variant that raises klotho scored higher on thinking tests.
This 2014 study looked at people with one copy of a gene variant called KL-VS. This variant raises klotho in the blood. They scored better on thinking tests in three separate groups of people. Mice with more klotho learned faster. The effect ran through NMDA receptors, which help brain cells strengthen their connections. Human observational and animal data.
5. A klotho piece given outside the brain improved mouse brain function.
This 2017 study gave young, old, and Parkinson's model mice a piece of klotho called KL1. It was injected into the body, not the brain. Thinking and movement improved. The klotho piece did not enter the brain. How it acts on the brain from outside is still unknown. Animal data.
6. One low dose improved memory in old monkeys.
This 2023 study gave old rhesus monkeys one shot of klotho under the skin. The low dose improved working memory. Higher doses did not. Researchers call this pattern an inverted U. Animal data.
How much research exists
Many mouse studies and one monkey study. Human studies only measured blood levels or looked at gene variants. No human has received klotho in a published trial.
Facts
- Formula: none. It is a large protein with sugar chains attached.
- Weight: about 130,000 daltons for the full protein. About 62,000 to 65,000 daltons for the KL1 piece.
- CAS number: none found
- Sequence: 1,012 amino acids. Full sequence not listed here.
- Time in the blood: no human data. In monkeys, it was measured in the blood up to 52 hours after one shot.
- Storage: keep in the fridge.
Legal status
Not approved by the FDA or any other agency. No human trial results have been published.
For research use only. Not for human use. Nothing here is medical advice.