Follistatin molecular structure
Follistatin molecular structure
Experimental
💊Muscle Building

Follistatin

Also known as: Myostatin Inhibitor

MW

36000.00 Da

CAS

136470-78-5

Routes

2 routes

Follistatin is a naturally occurring glycoprotein that functions as a potent inhibitor of myostatin, activin, and other members of the TGF-β superfamily. Produced primarily in the liver, skin, and reproductive tissues, follistatin binds and neutralizes myostatin — the body's primary negative regulator of muscle growth — effectively removing the "brake" on muscle hypertrophy. The two main isoforms, FS315 (tissue-bound) and FS344 (circulating), have different tissue distributions and potencies. Gene therapy and recombinant follistatin have demonstrated dramatic muscle growth in animal models, including the famous "mighty mice" experiments showing 100-200% increases in muscle mass. Follistatin gene therapy has entered early clinical trials for muscular dystrophy.

Research Use OnlyFor educational and research purposes only

Research Applications

Muscular Dystrophy

Gene therapy using AAV-follistatin has entered Phase 1/2 clinical trials for Becker and Duchenne muscular dystrophy, showing improved muscle function and 6-minute walk test performance.

Muscle Wasting

Research for sarcopenia, cachexia, and disuse atrophy. Follistatin's myostatin-blocking mechanism promotes muscle growth even in catabolic conditions.

Fertility Research

Activin/follistatin balance regulates FSH secretion and follicular development, with implications for fertility treatment.

Metabolic Improvement

Follistatin-induced muscle mass increase enhances glucose disposal and insulin sensitivity through increased metabolic sink tissue.

Mechanism of Action

Follistatin binds myostatin and activin with high affinity, preventing their interaction with ActRIIB (activin receptor type IIB). Myostatin normally signals through ActRIIB→Smad2/3 to suppress muscle protein synthesis and satellite cell activation. By neutralizing myostatin, follistatin removes this inhibition, allowing mTOR-mediated protein synthesis and satellite cell proliferation to proceed unchecked, resulting in marked muscle hypertrophy and hyperplasia.

Biological Pathways

Myostatin/ActRIIB/Smad2/3 inhibition. Released mTOR/p70S6K for protein synthesis. Enhanced satellite cell proliferation through removed Smad-mediated cell cycle inhibition. Activin neutralization for reproductive and metabolic effects.

Dosage Information

Typical dosage ranges for research applications. Always verify with current literature.
Typical Dose
100 mcg
Dose Range
50 - 200 mcg
Frequency
Daily for 7-30 day cycles
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Dosage calculation parameters
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Calculation Results

Concentration
2.5 mg/ml
Dose Volume
0.1 ml0.100 ml
Insulin Syringe
10 units
Doses per Vial
2020 doses @ 250 mcg

Syringe Fill Level (100u syringe)

05010010.0uunits
0u10.0 / 100 units (10%)100u

Protocols

No protocols featuring this peptide yet.

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Stability & Storage

Follistatin is a large glycoprotein requiring careful handling. Store lyophilized form at -20°C or below. Reconstitute in sterile buffer with carrier protein (0.1% BSA). Use within 7 days at 2-8°C. Sensitive to freeze-thaw, agitation, and temperature extremes. Gene therapy approaches avoid protein stability challenges.

Side Effects & Precautions

Limited human safety data. Theoretical concerns include potential effects on reproductive hormones (activin/FSH regulation), liver function, and uncontrolled tissue growth. Gene therapy trials show acceptable safety profiles in muscular dystrophy patients. As a research compound, comprehensive side effect data is not available.

Research Use Only. This information is for educational and research purposes only. Not intended for medical advice or self-medication.

Regulatory Status

Experimental

Not FDA-approved as a therapeutic protein. Gene therapy vectors expressing follistatin (AAV1-FS344) are in clinical trials under IND status for muscular dystrophy. Research compound. WADA-prohibited under S4.2 (Myostatin Inhibitors).

Research Studies

Follistatin Gene Therapy for Muscular Dystrophy

Mendell JR, Sahenk Z, Malik V, et al.

Molecular Therapy
2015
View Source

Follistatin Inhibits Myostatin and Enhances Muscle Growth

Lee SJ, McPherron AC.

Proceedings of the National Academy of Sciences
2001
View Source

Myostatin/Activin Signaling in Muscle Regulation

Lee SJ.

Annual Review of Cell and Developmental Biology
2004
View Source
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