Follistatin-315
FST-315 · Follistatin isoform 315
Truncated isoform of follistatin that potently blocks myostatin and activin to maximize muscle hypertrophy.
Half-Life
~3–4 days (long-acting due to size and binding)
MW
N/A
Amino Acids
N/A
Evidence
Preclinical
Regulatory Status
Research compound
In Plain English
A freely circulating version of the myostatin blocker that works throughout the whole body rather than staying locally. Potentially more potent for systemic muscle growth than FST-344 because it spreads freely in blood rather than binding to local tissue.
Overview
Follistatin-315 is a shorter isoform of follistatin produced by alternative splicing. Unlike Follistatin-344 (which binds heparin and is more locally retained), FST-315 circulates more freely and has greater systemic myostatin-blocking activity. Research shows extraordinary muscle mass increases — in some animal models near-doubling of muscle mass. Highly discussed in elite performance research for myostatin inhibition and anti-aging muscle preservation.
Common Formats
- Injectable (intramuscular)
- Injectable (subcutaneous)
Storage Notes
Freeze at -20°C. Reconstituted: refrigerate, use within 14 days.
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Related Compounds
Follistatin-344
A naturally occurring glycoprotein that inhibits myostatin and activin, studied for its dramatic muscle growth and satellite cell activation properties.
IGF-1 LR3
A potent long-acting variant of IGF-1 with a 13-amino acid extension and substitution that dramatically extends its half-life and prevents protein binding.
TB-500
A synthetic version of the naturally occurring peptide Thymosin Beta-4, studied for tissue repair, inflammation reduction, and vascular remodeling.
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