Head to head
Klotho against GDF11
Two proteins that became longevity headlines and then met better measurement. Nobody has given klotho to a human in a published trial, and the human assay built to measure GDF11 properly found it does not decline with age and that higher levels track with frailty.
Column A
KlothoAlpha-Klotho (secreted s-KL) and klotho-based therapies
Nobody has given klotho to a human in a published trial. Blood levels track with longevity and cognition; a gene therapy (KLTO-202) is heading toward human trials, while products sold online as 'klotho peptide' are not the protein studied.
Column B
GDF11Growth/differentiation factor 11
The young blood factor. Two famous 2013 and 2014 papers said it declines with age and rejuvenates. The human assay built to measure it properly found it does not decline, and that higher levels track with frailty.
Side by side, on the facts we can check
| Attribute | Klotho | GDF11 |
|---|---|---|
| Category | Longevity | Anti-aging |
| FDA status | No approved product; gene therapy pre-IND | Not an approved drug. No human trial of GDF11 administration has ever been run. |
| Half-life | Endogenous protein; therapeutic forms not yet defined in humans | Circulates as a latent complex. No verified circulating half-life is asserted here. |
| Molecular weight | 116,181 Da for the 1,012 amino acid alpha-klotho protein (UniProt Q9UEF7); products sold as 'klotho peptide' are short fragments, not this protein | Precursor 407 amino acids, 45,091 Da. Mature signalling domain is residues 299 to 407, 109 amino acids, the same length as myostatin's (UniProt O95390). |
| Mechanism | Soluble klotho acts as a co-receptor for FGF23 and modulates insulin/IGF-1, Wnt and oxidative-stress signaling; its decline with age is linked to kidney, vascular and cognitive aging. | Signals through activin type II receptors and SMAD2/3, the same axis as myostatin, and is more potent than myostatin at inducing SMAD2 phosphorylation in myocardium. That receptor sharing plus the near-identical mature domain is not a curiosity: it is the direct cause of the measurement dispute, because reagents and assays struggle to tell the two apart. |
| Human studies cited | 2 | 1 |
| Legal status, US | Not approved; research use only | Not a drug; endogenous hormone and research infusion peptide |
Frequently asked questions
What is the difference between Klotho and GDF11?
Klotho: Nobody has given klotho to a human in a published trial. Blood levels track with longevity and cognition; a gene therapy (KLTO-202) is heading toward human trials, while products sold online as 'klotho peptide' are not the protein studied. GDF11: The young blood factor. Two famous 2013 and 2014 papers said it declines with age and rejuvenates. The human assay built to measure it properly found it does not decline, and that higher levels track with frailty.
Which has stronger research evidence, Klotho or GDF11?
This database does not grade compounds. It counts what was run in people: 2 of the 6 studies cited on the Klotho profile were human work, against 1 of 6 for GDF11. Those counts are of our own citation lists and understate any larger literature, and neither is a recommendation.
Are Klotho and GDF11 FDA-approved?
Klotho: No approved product; gene therapy pre-IND. GDF11: Not an approved drug. No human trial of GDF11 administration has ever been run..
Related posts
Blog articles that cover Klotho or GDF11, newest first.
- Longevity / Sep 8, 2026 / 12 minPeptides for Longevity: What the Evidence Actually Shows in 2026
- Research / Sep 8, 2026 / 11 minNew Peptides and Longevity Compounds in 2026: What Is Actually New, What Is Newly Legal, and What Is Just New to Vendors
- Longevity / Sep 8, 2026 / 8 minKlotho Explained: Protein, Peptide, Gene Therapy or Supplement?
Reviewed Sep 2026. This page sets two published records side by side. It is educational, it is not medical advice, and it contains no dosing protocols or recommendations for personal use.