Head to head
GDF11 against Myostatin
Two closely related members of the same protein family, one famous for rejuvenation claims and one for muscle. Their similarity is not incidental: assay cross-reactivity between them is part of why the early GDF11 results did not hold up.
Column A
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.
Column B
MyostatinMyostatin (growth/differentiation factor 8)
The brake on muscle growth. Knock it out in a mouse and you get a mouse twice as muscular, which launched a field. In primates the dominant brake turns out to be a different protein.
Side by side, on the facts we can check
| Attribute | GDF11 | Myostatin |
|---|---|---|
| Category | Anti-aging | Muscle & Performance |
| FDA status | Not an approved drug. No human trial of GDF11 administration has ever been run. | Myostatin is an endogenous protein, not a drug. Drugs targeting the pathway are investigational; apitegromab has phase 3 data in spinal muscular atrophy. |
| Half-life | Circulates as a latent complex. No verified circulating half-life is asserted here. | Circulates as a latent complex; no single agreed circulating half-life is asserted here. |
| Molecular weight | 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). | Precursor 375 amino acids, 42,750 Da. Mature signalling domain is residues 267 to 375, 109 amino acids, circulating as a dimer (UniProt O14793). |
| Mechanism | 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. | Circulates as a latent disulfide-linked dimer held inactive by its own propeptide. Once activated it signals through activin type II receptors, principally ActRIIB, with type I receptors ALK4 and ALK5, through SMAD2 and SMAD3, to suppress muscle protein synthesis and satellite cell activity. Activin A signals through the same type II receptors, which is the whole reason receptor-level blockade and ligand-level blockade behave so differently. |
| Human studies cited | 1 | 4 |
| Legal status, US | Not a drug; endogenous hormone and research infusion peptide | Not a drug; endogenous hormone and research infusion peptide |
Frequently asked questions
What is the difference between GDF11 and Myostatin?
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. Myostatin: The brake on muscle growth. Knock it out in a mouse and you get a mouse twice as muscular, which launched a field. In primates the dominant brake turns out to be a different protein.
Which has stronger research evidence, GDF11 or Myostatin?
This database does not grade compounds. It counts what was run in people: 1 of the 6 studies cited on the GDF11 profile were human work, against 4 of 6 for Myostatin. Those counts are of our own citation lists and understate any larger literature, and neither is a recommendation.
Are GDF11 and Myostatin FDA-approved?
GDF11: Not an approved drug. No human trial of GDF11 administration has ever been run.. Myostatin: Myostatin is an endogenous protein, not a drug. Drugs targeting the pathway are investigational; apitegromab has phase 3 data in spinal muscular atrophy..
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.