Follistatin 344
Follistatin 344 is an overwhelmingly powerful, endogenously occurring autocrine glycoprotein that reigns as the absolute apex predator of myostatin inhibition. Because the human body inherently restricts muscle growth to conserve energy via the myostatin pathway, athletes and those suffering from severe muscle-wasting pathologies utilize Follistatin 344 to violently remove these biological limits. Delivered via isolated, localized injections, it provokes rampant, unchecked muscle hyperplasia (new fiber creation) and explosive localized hypertrophy that transcends normal generic limits.
Quick Stats
Scientific Data
Mechanism of Action
Follistatin 344 is a monomeric glycoprotein that binds and neutralizes myostatin (GDF-8) and activins with high affinity. Myostatin is the primary negative regulator of muscle growth — it acts as a biological brake that limits skeletal muscle size.
By binding and inactivating myostatin, Follistatin 344 removes this brake, allowing increased muscle protein synthesis and hypertrophy beyond normal genetic limits. The 344 designation refers to the specific isoform (344 amino acids) that provides the broadest myostatin/activin neutralization spectrum. Animals with natural myostatin gene knockouts (Belgian Blue cattle, Mighty Mouse) display extreme musculature — demonstrating what myostatin inhibition achieves. Follistatin is also involved in FSH regulation, adding a hormonal dimension to its use.
Source: PMID: 17108139
Background & History
Follistatin-344 is an isoform of follistatin — a glycoprotein first purified from ovarian follicular fluid in 1987 by four independent research groups. Follistatin's primary mechanism is sequestration of myostatin (GDF-8), the master inhibitor of muscle growth. By binding and neutralizing myostatin, follistatin removes the physiological brake on muscle hypertrophy. The -344 isoform has high heparan sulfate binding affinity, concentrating it in muscle tissue. A single intramuscular gene therapy injection of follistatin in animal models produced up to 2× muscle mass increase.
Research Use Cases
- ✓Muscle wasting diseases: muscular dystrophy, sarcopenia
- ✓Muscle hypertrophy research with myostatin inhibition
- ✓Cancer cachexia management
- ✓Athletic performance research (banned in sport)
Dosing Protocol
| Typical Dose | 100-300 mcg/day |
| Frequency | 1× daily for 10-30 days |
| Half-Life | ~3-6 hours (estimated) |
| Common Vial Sizes | 1 mg |
Dosing Protocols
Research Protocol
Body-Weight Dosing Reference
Estimated doses extrapolated from the published research range of 100–300 mcg/day (referenced to 70 kg / 154 lb). These are approximations — consult a qualified healthcare provider for personalised guidance.
| Weight | Low Dose | Target Dose | High Dose |
|---|---|---|---|
| 120 lb(54 kg) | 77 mcg | 154 mcg | 231 mcg |
| 140 lb(63 kg) | 90 mcg | 180 mcg | 270 mcg |
| 160 lb(73 kg) | 104 mcg | 209 mcg | 313 mcg |
| 180 lb(82 kg) | 117 mcg | 234 mcg | 351 mcg |
| 200 lb(91 kg) | 130 mcg | 260 mcg | 390 mcg |
| 220 lb(100 kg) | 143 mcg | 286 mcg | 429 mcg |
| 250 lb(113 kg) | 161 mcg | 323 mcg | 484 mcg |
💉 For exact syringe units based on your vial concentration, use the Follistatin 344 Reconstitution Calculator →
Administration
Expected Timeline
Who Is It For?
Muscle Hypertrophy
LowMost potent natural myostatin inhibitor. Animal data is compelling. Human evidence is very limited.
Hormone Regulation
LowCaution: Follistatin also binds activin, affecting FSH levels. May impact reproductive hormones.
Reconstitution Example
Safety & Considerations
Research peptide with very limited human safety data. Also binds activin — may impact FSH and reproductive function. Monitor FSH, LH, and testosterone during use. Not recommended for individuals trying to conceive. Very experimental.
Regulatory & Legal Status
Not currently on the WADA 2026 Prohibited List. Policies may change — verify before competition.
Research Chemical
US Compounding: Not eligible / not available
⚠️ This information is for educational purposes only and may not reflect the most current regulatory updates. Always verify with official FDA, WADA, and jurisdiction-specific sources before use.
Interactions & Contraindications
Ban: WADA anti-doping — prohibited in competitive sport. Long-acting: effects may last weeks to months per injection. Potential interaction with reproductive hormone axis (FSH inhibition) — monitor in women. Improperly sourced follistatin carries bacterial contamination risk; source quality is critical.
Synergies & Common Stacks
Follistatin removes the myostatin brake on muscle growth; IGF-1 LR3 simultaneously drives the anabolic signaling. Additive muscle hypertrophy potential.
GH/IGF-1 elevation (Ipamorelin) provides anabolic substrate while follistatin maximizes the muscle's capacity to respond by inhibiting myostatin.
Dosing Quick Reference
Frequently Asked Questions
Can Follistatin really inhibit myostatin?▼
Does Follistatin affect fertility?▼
References
- Nakamura T et al. “"Follistatin, an inhibitor of activin".” Science (1990). PMID: 2173733
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