Anti-aging Growth Factors Myostatin Inhibitors Under research

Follistatin 344

Also known as: FST-344, Folistatina

Follistatin is an autocrine glycoprotein that binds to TGF-β family peptides, inhibiting their activity. The 344 variant (FST-344) has been heavily investigated in bodybuilding and medicine for its extremely high affinity to bind and block myostatin, the primary negative regulator of muscle mass. By blocking myostatin, it triggers uncontrolled hypertrophic muscle growth in animal subjects.

Mechanism of action

Irreversibly binds to serum and tissue myostatin, preventing it from activating its receptor (ActRIIB).
Suppressing the myostatin inhibitory pathway allows anabolic signals (like IGF-1) to fully dominate, causing hyperplasia and hypertrophy.
The 344 isoform is the most studied for its primarily localized action in muscle tissue following injection, minimizing impact on other organs.

Uses & indications

Massive muscle development: Used off-label by professional athletes.
Muscular dystrophy research: Potential treatment for muscle-wasting conditions like Sarcopenia.

Effects

Drastic increases in fat-free muscle mass and strength in a short period. Secondary fat reduction due to increased basal metabolic rate.

Considerations & contraindications

High risk of systemic tissue alterations (unwanted growth of organs or connective tissues) if its action generalizes.
Very short cycle times (10-20 days).
Frequent compound degradation; difficult to find in pharmaceutical grade.

Regulatory approval

Not approved. Banned by WADA.

Dosage

In sports research protocols, it is usually used at 100mcg/day divided bilaterally for a maximum of 10-20 days.

Storage

Lyophilized at -20°C. Reconstituted it is fragile, keep refrigerated and use within 7 days.

Technical data

Regulatory status Under research

Molecular weight ~37.8 kDa (Glicoproteína entera)

Half-life Indeterminada, efecto local prolongado

Administration routes Intramuscular profunda