Follistatin 344
Also known as: FST-344 · Follistatin · FS-344
Follistatin 344 binds and neutralizes myostatin (GDF-8) with high affinity, preventing myostatin from binding its receptor (ActRIIB). Since myostatin is the primary inhibitor of skeletal muscle growth, neutralizing it removes this brake on muscle hypertrophy. It also inhibits activin A...
What It Is
Follistatin 344 binds and neutralizes myostatin (GDF-8) with high affinity, preventing myostatin from binding its receptor (ActRIIB). Since myostatin is the primary inhibitor of skeletal muscle growth, neutralizing it removes this brake on muscle hypertrophy. It also inhibits activin A (another TGF-beta family member that limits muscle growth). This produces dramatic increases in satellite cell activation, protein synthesis, and muscle fiber hypertrophy - effects seen in animal studies include 200-300% increase in muscle mass. Follistatin 344 also inhibits FSH, making it a concern in reproductive axis management.
Supplies Needed
Reconstitution solvent - small volume for high-concentration
Intramuscular injection
Sterilization
Storage
Store at -20C. Extremely sensitive protein - do not leave at room temperature. Avoid repeated freeze-thaw cycles.
Refrigerate at 2-8C; use within 14-30 days. Handle very gently - do not agitate.
This information is provided for educational and research purposes only. Not approved for human consumption by the FDA or any regulatory body. Always consult a qualified medical professional.
Dosing Protocols
Timing: Post-workout or morning. Extreme protocol - short bursts prevent FSH suppression complications. Start at lowest dose.
↓ Apply these values to the reconstitution calculatorTiming: Post-workout. Most common research protocol; significant FSH suppression expected; PCT monitoring recommended
↓ Apply these values to the reconstitution calculatorTiming: Post-workout split across multiple injection sites. Extreme hypertrophy protocol; reproductive hormone monitoring essential; some researchers combine with gene therapy vectors (not recommended for human use)
↓ Apply these values to the reconstitution calculatorWeekly Timeline
| Week | Expected Effects |
|---|---|
| Week 1 | Rapid increase in muscle fullness and size; enhanced pump during training; noticeable hypertrophy beginning |
| Week 2 | Significant lean mass gains (5-10 lbs); increased strength; muscle hardness |
| Week 4 | (2 weeks post-cycle) Retained gains with new muscle fibers established; FSH levels beginning to recover |
| Week 12 | Full reproductive axis recovery; retained muscle gains; ready for next cycle |
Reconstitution Calculator
1 unit on U-100 syringe = 0.01 mL · Always label your vial after reconstitution
Injection Technique & Reconstitution
- Remove flip-top cap from the vial
- Swab rubber stopper with alcohol swab
- Draw 1 mL bacteriostatic water into syringe
- Inject slowly and gently down the vial wall
- Gently swirl until dissolved - follistatin is a large glycoprotein and dissolves slowly
- Label with date; refrigerate at 2-8C immediately
- Very sensitive to temperature and agitation - handle with extreme care
Use our free Follistatin 344 calculator to get the exact syringe units for your vial size and dose.
Mechanism of Action
Follistatin 344 binds and neutralizes myostatin (GDF-8) with high affinity, preventing myostatin from binding its receptor (ActRIIB). Since myostatin is the primary inhibitor of skeletal muscle growth, neutralizing it removes this brake on muscle hypertrophy. It also inhibits activin A (another TGF-beta family member that limits muscle growth). This produces dramatic increases in satellite cell activation, protein synthesis, and muscle fiber hypertrophy - effects seen in animal studies include 200-300% increase in muscle mass. Follistatin 344 also inhibits FSH, making it a concern in reproductive axis management.
Key Research Papers
Demonstrated that follistatin overexpression produced 200-300% increase in muscle mass in animal models via myostatin inhibition and satellite cell activation.
View on PubMed →Stacks Well With
Follistatin 344 removes myostatin brake on muscle growth while IGF-1 LR3 activates mTOR/protein synthesis. Combined they produce synergistic extreme hypertrophy.
PEG-MGF activates satellite cells while Follistatin 344 ensures myostatin does not inhibit their differentiation into new muscle fibers. Highly synergistic for new fiber formation.
Frequently Asked Questions
Follistatin 344 is used for extreme muscle hypertrophy via myostatin inhibition. By neutralizing myostatin - the primary protein that limits muscle growth - follistatin 344 removes the natural brake on muscle size, producing significant lean mass gains.
Animal studies show 200-300% muscle mass increases with complete myostatin inhibition. In humans, realistic gains from a 10-day cycle are 5-15 lbs of lean mass, retained long-term due to new muscle fiber formation.
Yes - Follistatin significantly suppresses FSH (follicle-stimulating hormone) because it neutralizes activin A (which normally stimulates FSH). This can reduce sperm production in men and affect fertility. Effects are typically reversible after the cycle.
Legal Status by Region
This information is provided for educational and research purposes only. Not approved for human consumption by the FDA or any regulatory body. Always consult a qualified medical professional.