For research and educational purposes only. Not intended for human consumption.
Follistatin 344
Limited Research- •Gene therapy trials for muscular dystrophy ongoing
- •WADA prohibited status since 2019
- •FS-315 isoform characterization studies
Myostatin Inhibitor | TGF-β Antagonist for Muscle Research
Overview
What is Follistatin 344?
Follistatin 344 (FS-344) is a naturally occurring glycoprotein that inhibits myostatin and activin A, members of the TGF-β superfamily that suppress muscle growth. The FS-344 gene encodes a 344-amino acid precursor that is cleaved to produce the circulating FS-315 isoform. Gene therapy studies in primates and human clinical trials for muscular dystrophy have demonstrated significant muscle hypertrophy and strength gains. WADA banned since 2019. Banned by WADA
Key Benefits
Myostatin and activin A inhibition, potential muscle growth enhancement, studied for muscular dystrophy therapy.
Mechanism of Action
Binds and neutralizes myostatin and activin A, preventing their interaction with ActRIIB receptors on muscle cells. This blocks TGF-β signaling that normally suppresses muscle growth, allowing enhanced hypertrophy.
Molecular Information
Pharmacokinetics
Research Indications
Myostatin Inhibition
Blocks myostatin from binding to muscle cell receptors, removing natural growth suppression.
Activin A Blockade
Also inhibits activin A, providing dual-action anti-catabolic effect greater than myostatin-only inhibitors.
Satellite Cell Activation
Research suggests follistatin may directly promote satellite cell proliferation for muscle regeneration.
Research Protocols
Disclaimer: Most follistatin research involves gene therapy (AAV vector delivery) providing sustained expression. Injectable peptide has ~90-minute half-life and very limited human data. Results from gene therapy studies should not be extrapolated to injectable peptide use.
| Goal | Dose | Frequency | Route |
|---|---|---|---|
| Research Protocol (Anecdotal) | 100mcg | Once daily | SubQ |
| Higher Dose Protocol (Anecdotal) | 200mcg | Once daily (max recommended) | SubQ |
Timing: No established optimal timing. Short half-life (~90 min) means effects may not persist between daily doses.
Peptide Interactions
How to Reconstitute
Important: Always use bacteriostatic water (BAC). Sterile technique is essential.
Store lyophilized powder at -20°C until use
Add sterile/bacteriostatic water slowly down vial side
Gently swirl - do not shake vigorously as protein may denature
Solution should be clear - discard if cloudy
Use reconstituted solution within 7 days
Store reconstituted solution at 2-8°C, never freeze
Dosing Calculator
Calculate your injection volume with visual dosing guide
To obtain 250 mcg from this solution:
Draw 0.10 mL=10 units
(1 mL = 100 units on any insulin syringe)
Draw to this mark for 250 mcg
This calculator is for research purposes only. Always verify calculations and consult protocols.
Quality Indicators
Extremely Limited Human Peptide Data
Most research involves gene therapy, not injectable peptide. Efficacy and safety of subcutaneous peptide poorly established.
Very Short Half-Life (~90 minutes)
Native follistatin is rapidly cleared. Systemic muscle effects from daily injection are questionable.
WADA Banned Substance
Prohibited in sports since 2019. Subject to doping detection methods.
Excessive Dosing Risk
Case report of vision impairment at 1mg single dose (10x typical). Never exceed 200mcg/day.
Third-Party Testing Essential
Given limited regulation and high potential for counterfeit, COA verification is critical.
What to Expect
- •Week 1-2: No reliable timeline established for injectable peptide use
- •Week 2-4: Gene therapy studies showed measurable changes by week 8
- •Important: Most dramatic results (15% muscle increase) are from gene therapy providing sustained expression
- •Injectable peptide effects likely much more modest due to rapid clearance
Side Effects & Safety
Side Effects
- •CRITICAL: Most safety data is from gene therapy, not injectable peptide
- •Gene therapy trials showed no serious adverse events in BMD patients
- •Potential FSH suppression - may affect reproductive function
- •Minor LDL cholesterol increase reported (~8 mg/dL) in some subjects
- •Theoretical concerns: bone density reduction, organ fibrosis with chronic TGF-β inhibition
- •Case report of vision impairment at 10x dose - never exceed recommended amounts
- •Not recommended for those with active cancer
- •Contraindicated in pregnancy
When to Stop
- •Vision changes
- •Signs of reproductive dysfunction
- •Significant cholesterol changes
- •Any unexpected symptoms
- •As directed by healthcare provider
References
3 StudiesGene Delivery in Nonhuman Primates (2009)
Primate | AAV1-FS344 | 15 months | 15% circumference increase at 8 weeks
AAV1-FS344 injection into quadriceps produced 15% circumference increase at 8 weeks, persisting 15+ months. Muscle fiber diameter increased significantly.
Phase 1/2a Gene Therapy for BMD (2015)
Human | AAV1.CMV.FS344 | 6 BMD patients | 1 year | 6-minute walk test improvements up to +125 meters
First human gene therapy trial. Patients showed muscle fiber diameter increase and 35-43% reduction in fibrosis.
Long-term Muscle Mass Enhancement (2008)
Mouse | Multiple vectors | Long-term follow-up | 194-327% muscle mass increase
Transgenic mice expressing high follistatin levels showed 194-327% muscle mass increase. Effects persisted over 2 years.
Quick Start Guide
Research Disclaimer
Follistatin 344 is sold for laboratory research purposes only and is not intended for human or animal consumption. The information provided on this page is compiled from published research, veterinary studies, and anecdotal reports for educational purposes. This content does not constitute medical advice, diagnosis, or treatment recommendations. Any research involving Follistatin 344 must comply with all applicable local, state, and federal regulations. BioInfinity Lab makes no claims regarding the safety or efficacy of Follistatin 344 for any purpose. Consult qualified professionals for any research applications.