Follistatin 344 Protocol Guide
Follistatin 344 is a naturally occurring glycoprotein that binds and neutralizes myostatin (GDF-8) and activin A, two TGF-beta superfamily members that act as endogenous brakes on skeletal muscle growth. By antagonizing myostatin signaling, Follistatin 344 removes the primary biological limiter of muscle hypertrophy, enabling increased satellite cell activation, muscle protein synthesis, and lean mass accretion. The 344 isoform is the full-length variant with broadest tissue distribution and most potent systemic myostatin binding. This protocol covers subcutaneous dosing at 100mcg daily for short 10-30 day cycles, reproductive hormone monitoring, reconstitution, and hypertrophy stacking strategies.
Protocol Overview
- Compound
- Follistatin 344 (FS344)
- Category
- Myostatin Inhibitor / Muscle Growth
- Mechanism
- Binds and neutralizes myostatin (GDF-8) and activin A; removes endogenous muscle growth inhibition
- Molecular Weight
- ~36 kDa (glycoprotein)
- Half-Life
- ~2-3 hours (estimated)
- Form
- Lyophilized powder (1mg vials)
- Route
- Subcutaneous
- Frequency
- 1-2x daily
- Cycle Length
- 10-30 days on, 60+ days off
Dosing Protocol
| Protocol | Dose | Frequency | Route | Duration |
|---|---|---|---|---|
| Loading Phase | 100 mcg | 2x daily | SubQ | 3-5 days |
| Standard | 100 mcg | 1x daily | SubQ | 10-30 days |
| Conservative | 50 mcg | 1x daily | SubQ | 10-20 days |
Key principle: Short cycles are critical. Follistatin 344 also binds activin A, which plays roles in FSH regulation and reproductive function. Extended cycles may suppress FSH levels. Keep cycles under 30 days with extended 60+ day recovery periods. Monitor reproductive hormones.
Reconstitution Guide
Standard Reconstitution
- Vial: 1mg Follistatin 344
- Diluent: 1mL bacteriostatic water
- Concentration: 1mg/mL (1,000mcg/mL)
- 100mcg dose: 10 units on insulin syringe
- Vial yield: 10 doses at 100mcg
Storage & Handling
- Pre-reconstitution: Freeze at -20°C (protein)
- Post-reconstitution: Refrigerate at 2-8°C
- Stability: Use within 14 days (protein is fragile)
- Handle carefully: Do not shake; swirl gently
Expected Timeline
Side Effects & Monitoring
Common Side Effects
- Injection site reactions (mild)
- Joint discomfort during rapid strength gains
- Potential FSH suppression (activin A binding)
- Mild muscle cramping
Follistatin is a naturally occurring protein, but exogenous administration at supraphysiological levels may affect reproductive hormones.
Precautions
- Monitor FSH, LH, and reproductive hormones
- Keep cycles short (10-30 days max)
- Extended rest periods required (60+ days)
- May affect fertility temporarily
- Not recommended for women trying to conceive
- Contraindicated with active cancer
Stacking Recommendations
Compatible Compounds
- PEG-MGF: Satellite cell activation synergy
- CJC-1295/Ipamorelin: GH support for muscle growth
- BPC-157: Tissue repair and joint protection
- Epicatechin: Natural myostatin reduction complement
Popular Stacks
- Hypertrophy: FS344 100mcg/day + PEG-MGF post-WO
- Recomp: FS344 100mcg/day + CJC/Ipa 2x/day
- Recovery: FS344 100mcg/day + BPC-157 250mcg
Blood Work Recommendations
| Panel | Markers | Timing |
|---|---|---|
| Reproductive | FSH, LH, testosterone/estradiol | Baseline, Day 15, Day 30, 30 days post |
| Myostatin | Serum myostatin (if available) | Baseline, Day 15 |
| Metabolic | IGF-1, fasting glucose, insulin | Baseline, Day 30 |
| Body Composition | DEXA scan, strength testing | Baseline, Day 30, 60 days post |
FSH monitoring is the most critical marker. Follistatin 344 binds activin A which regulates FSH secretion. Temporary FSH suppression is possible with extended cycles.
Related Tools & Resources
