Muscle & Recovery
Follistatin 344 Dosing & Reconstitution Calculator
Follistatin 344 — a 344-amino-acid isoform of Follistatin that binds and neutralizes myostatin (GDF-8), inhibiting muscle growth suppression. Research dose: 100 mcg. 1 mg vial.
TL;DR — Follistatin 344 is the predominant circulating isoform of Follistatin, acting as a potent myostatin antagonist. Standard vial: 1 mg in 1 mL sterile BAC water (1,000 mcg/mL). Typical research dose: 100 mcg. Must be stored at -20°C lyophilized.
⚠ Note — ⚠ Large protein — store lyophilized at -20°C. Minimize freeze-thaw cycles. Add carrier protein (BSA) if storing dilute solutions.
100 mcg
Start Dose
1 mg
Vial
1 mL
BAC Water
1,000
mcg/mL
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Frequently Asked
How do I reconstitute Follistatin 344?
Add 1 mL of sterile Bacteriostatic Water to a 1 mg Follistatin 344 vial, injecting slowly down the glass wall. This yields 1,000 mcg/mL. For a 100 mcg dose, draw to the 10 line on a 100-unit insulin syringe. Do not vortex — the large protein structure is shear-sensitive.
What is Follistatin 344 and how does it inhibit myostatin?
Follistatin 344 is an isoform of Follistatin, a glycoprotein that binds and neutralizes TGF-β superfamily members including myostatin (GDF-8) and activin A. By sequestering myostatin, it removes its inhibitory signal on satellite cell proliferation and muscle fiber hypertrophy.
How does Follistatin 344 differ from Follistatin 315?
Follistatin 315 lacks the heparan-sulfate-binding C-terminal domain present in FS-344. FS-315 circulates freely in plasma; FS-344 is cell-associated due to heparan sulfate binding. For systemic muscle research, FS-344 may have different tissue distribution than FS-315.
What storage conditions does Follistatin 344 require?
Store lyophilized Follistatin 344 at -20°C or -80°C, protected from light. Once reconstituted, aliquot into single-use volumes and store at -80°C. Avoid more than two freeze-thaw cycles. For working solutions below 10 mcg/mL, add 0.1% BSA to prevent adsorption to plasticware.
Peptide Intelligence
What is the molecular weight of Follistatin 344?
Follistatin 344 has an apparent molecular weight of approximately 35–45 kDa by SDS-PAGE (higher than predicted 37.4 kDa due to glycosylation). The core polypeptide of 344 amino acids has a predicted MW of 37.4 kDa; N-linked glycosylation at three sites adds significant mass and influences bioavailability.
Is Follistatin 344 more effective than Follistatin 315?
Comparative efficacy depends on research context. In systemic circulation, FS-315 has longer half-life due to reduced heparan sulfate sequestration. For local tissue effects (e.g. intramuscular gene delivery studies), FS-344 shows greater local retention and prolonged myostatin inhibition within target tissue.
Also Explore
Primary Sources
Lee & McPherron — Myostatin Inhibition (2001)
Rodino-Klapac et al. — Follistatin Gene Delivery (2009)
Data last reviewed 2026-04-20 · Methodology →
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