Technical Data Sheet
Follistatin
Also Known As: FST, Follistatin 344, FS-344, Follistatin-344, FST344, Activin-binding protein, Myostatin inhibitor protein, Follistatin 288, FS-288, Follistatin peptide, Anti-myostatin, Muscle growth factor, Follistatin recombinant, FST-344 peptide, FST-344, myostatin inhibitor
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| Evidence Tier | Preclinical |
|---|---|
| Category | Muscle Growth & Performance |
| Class | Endogenous glycoprotein / activin-binding protein (recombinant) |
| Molecular Target | Myostatin (GDF-8) and activin A neutralization; prevents TGF-beta superfamily inhibition of muscle growth |
| Sequence | 344-residue glycoprotein |
| Molecular Weight | ~38 kDa |
| CAS | not standardized |
| Parent | Human FST gene |
| Mechanism | It permanently binds to and traps a protein called myostatin. Since myostatin is the exact chemical signal that tells muscles to stop growing, trapping it allows muscles to grow unrestricted. |
| Studied For | Muscle hypertrophy, Myostatin inhibition, Female fertility, Lean muscle mass increase, Anti-myostatin therapy, Duchenne muscular dystrophy models, Muscle wasting / sarcopenia research, Strength gain research, Body recomposition, Ovarian follicle development, Reproductive hormone regulation, FSH inhibition, Activin neutralization, Anabolic signaling amplification, Muscle fiber growth, Fat mass reduction via muscle increase, Athletic performance research, muscle growth, hypertrophy, bodybuilding, muscle wasting, sarcopenia |
| Administration Route | Injection Only |
| Form | lyophilized |
| Diluent | sterile or bacteriostatic water; gentle, avoid foaming |
| Storage Temperature | -4°F, dark |
| Light Sensitive | Yes |
| Freeze / Thaw | avoid |
| Reconstituted Shelf Life | 14 Days |
| Handling Notes | Large glycoprotein; rapidly cleared when injected. |
| Regulatory | Not FDA-approved; experimental. Named on the WADA 2026 Prohibited List under S4.3 as a myostatin-binding protein; prohibited at all times and a non-Specified substance. |
| Sources |