Follistatin 344
Also known as: FS-344
Follistatin 344 is a recombinant form of the naturally-occurring glycoprotein (344-residue splice variant) that inhibits activin and myostatin signaling. Clinical validation exists ONLY through small AAV gene-therapy phase 1/2 trials in Becker muscular dystrophy; recombinant injectable protein sold on the grey market has no clinical evidence. NOT FDA-approved. WADA-prohibited (myostatin inhibitor) and banned in competitive sport.
Who's worth your money for Follistatin 344
Every current seller, ranked by independent evidence — Merit Score, latest COA purity, and live $/mg (size-normalized). Prices refresh daily. Rankings are never paid.
Top Merit pick
Highest Merit Score (89) of 3 scored sellers
$162 · 1mg · 99.5% purity
Best value
Lowest $/mg among scored sellers
$321 · 10mg
Average price
$123.73/mg
Sellers
9
45-day trend
+14.8%
8 of 9 sellers have a current price· 1 stale hidden· 4 unverified hidden
Top Merit pick
🇺🇸 Peptidology89✓ verified at source · 3d ago · stale
$161.99/mg +30.9% vs avg$162
1mg
- 🇺🇸 Ruo Bio88
✓ verified at source · 9h ago
$38.00/mg -69.3% vs avg$38.00
1mg
no purity - 🇭🇰 zztai Peptide Ltd42
via Disclosed Labs · 10h ago
$32.10/mg -74.1% vs avg$321
10mg
no purity
Prices observed from public storefronts (last 24h), normalized to $/mg. "Evidence" is Merit's 0–100 Merit Score, derived only from observable verification evidence (methodology on /about); "Purity" is the latest independent COA. Some buy links are affiliate links — Merit may earn a commission at no extra cost to you, and where a vendor offers one, the code shown gets you a discount at their checkout. Affiliate status never affects price data, ranking, or the Merit Score (full policy on /disclosure). Research use only.
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About Follistatin 344
CAS
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Molecular formula
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Sequence
MVRARHQPGGLCLLLLLLCQFMEDRSAQAGNCWLRQAKNGRCQVLYKTELSKEECCSTGRLSTSWTEEDVNDNTLFKWMIFNGGAPNCIPCKETCENVDCGPGKKCRMNKKNKPRCVCAPDCSNITWKGPVCGLDGKTYRNECALLKARCKEQPELEVQYQGRCKKTCRDVFCPGSSTCVVDQTNNAYCVTCNRICPEPASSEQYLCGNDGVTYSSACHLRKATCLLGRSIGLAYEGKCIKAKSCEDIQCTGGKKCLWDFKVGRGRCSLCDELCPDSKSDEPVCASDNATYASECAMKEAACSSGVLLEVKHSGSCNSISEDTEEEEEDEDQDYSFPISSILEW
Typical dose range
100–200 mcg/day subcutaneous (research use; cycles of 10–30 days on, 3–4 weeks off)
Half-life
~90 minutes (recombinant injectable form); endogenous FST-315 isoform estimated ~10–15 hours
COAs for Follistatin 344
2 third-party tests across 2 vendors. Each card links to the full report.
12 citations indexed for Follistatin 344
review · 2026
Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance
Peptides are short chains of amino acids with a unique pharmacological niche between small-molecule drugs and large proteins. Their use in sports medicine is rapidly expanding, driven by patient demand for accelerated injury recovery and performance enhancement.
review · 2026
Therapeutic Peptides in Aesthetic, Metabolic and Endocrine Conditions: Effects, Safety, Clinical Applications, and Future Perspectives
Therapeutic peptides are short chains of amino acids used to treat metabolic and endocrine conditions such as obesity and type 2 diabetes.
Study · 2026
Grip strength as a systems biomarker of aging: neuromuscular junction constraints and biomarker decoupling in gene therapy
Grip strength has emerged as one of the most robust predictors of mortality, disability and healthspan across populations.
review · 2026
Myostatin Research: From Molecular Understanding to Clinical Translation for Musculoskeletal and Metabolic Disorders
Myostatin (Mstn), a well-characterized member of the transforming growth factor-β (TGF-β) superfamily, serves as a key negative regulator of skeletal muscle mass. Its overactivation is closely associated with the pathogenesis of various musculoskeletal and metabolic disorders.
Study · 2025
Gel Electrophoretic Detection of Black Market ACE-031
The usage of ACE-031 (Ramatercept), a dimeric fusion protein consisting of a human activin receptor IIB (ACVR2B) fragment linked to an Fc-part of human IgG1, is banned according to chapter S4.3 of the "WADA 2024 List of Prohibited Substances and Methods" due to its potential performance enhancing properties.
review · 2023
The elusive role of myostatin signaling for muscle regeneration and maintenance of muscle and bone homeostasis
Skeletal muscle is one of the leading frameworks of the musculo-skeletal system, which works in synergy with the bones. Long skeletal muscles provide stability and mobility to the human body and are primarily composed of proteins.