Understand the source comparison
Myostatin Pathway: Follistatin vs Other Inhibitors
Follistatin 344 is not the only approach to myostatin inhibition. Several compounds target the same pathway through different mechanisms. Follistatin 344 Binds myostatin/activin directly SC injection Research only 15-36% fiber size increase (primates) Short ha
No winner is assigned.
This page preserves a source comparison for education. It does not add a rating, recommendation or clinical judgment.
- Follistatin 344 is not the only approach to myostatin inhibition. Several compounds target the same pathway through different mechanisms.
- Follistatin 344
- Binds myostatin/activin directly
- SC injection
- Research only
- 15-36% fiber size increase (primates)
- Short half-life, requires daily dosing
- ACE-031
- Soluble ActRIIB decoy receptor
- IV infusion
- Failed Phase II
- Significant lean mass gains
- Nosebleeds, telangiectasia in trials
- Bimagrumab
- Anti-ActRII antibody
- Phase III (sarcopenia)
- 5-7% lean mass increase
- Limited to clinical settings
- YK-11
- Upregulates follistatin expression
- Oral
- Indirect myostatin inhibition
- No human clinical trials, steroidal
- Decorin
- Binds myostatin, TGF-beta
- Preclinical
- Modest effect vs follistatin
- Very limited human data
- FS gene therapy
- Sustained follistatin expression
- Single injection
- Experimental (Minicircle)
- 2 lb lean mass at 3 months
- Expensive, limited access
- ACE-031 (developed by Acceleron Pharma) showed promising muscle-building results in Phase I trials but was discontinued after Phase II due to adverse events including nosebleeds and small dilated blood vessels. The problem: ACE-031 blocks activin broadly, affecting pathways beyond muscle (Campbell et al. 2017, PubMed 27779229).
- Follistatin's advantage is specificity. It binds myostatin with extremely high affinity while its isoform distribution (FS-315 to muscle, FS-288 to gonads) provides some tissue selectivity. The trade-off is a short circulating half-life requiring daily injection, versus gene therapy approaches that produce sustained expression from a single treatment.
- For a broader view of peptides for muscle growth, follistatin sits at the most direct end of the myostatin inhibition spectrum. Growth hormone secretagogues like ipamorelin, GHRP-2, or MK-677 work through entirely different pathways (GH/IGF-1 axis) and can be stacked with follistatin without overlapping mechanisms.