Myostatin / TGF-β Signaling Research / Muscle Biology Research Compounds
Myostatin Inhibitor Peptides Research — Follistatin 344 & GDF-8 Signaling
Myostatin (growth differentiation factor 8, GDF-8) is a TGF-β superfamily cytokine that acts as the primary endogenous inhibitor of skeletal muscle growth. It is secreted by skeletal muscle cells, signals through the activin receptor IIB (ActRIIB) / ALK4-ALK5 complex, and activates SMAD2/3 transcriptional programs that suppress satellite cell activation and protein synthesis. Loss-of-function mutations in MSTN produce extraordinary muscle mass in cattle (Belgian Blue), dogs, sheep, and a small number of documented human cases. Follistatin 344 (FST344; a 344-residue glycoprotein isoform of the follistatin gene) is the primary endogenous myostatin antagonist — a secreted glycoprotein that binds myostatin (and activins) with high affinity, neutralizing ActRIIB signaling. FST344 and its shorter isoform FST288 are studied as pharmacological tools to characterize myostatin-pathway biology in muscle wasting, sarcopenia, and hypertrophy models. Research use only.
Compound identity
- Name
- Myostatin Inhibitor Peptides — Follistatin & Muscle Research Hub
- Class
- Myostatin / TGF-β Signaling Research / Muscle Biology Research Compounds
- Also known as
- myostatin inhibitor peptide, follistatin myostatin research, myostatin research compound, follistatin 344 myostatin, GDF-8 inhibitor research, muscle growth peptide research, myostatin blocker research, anti-myostatin peptide, follistatin muscle research, myostatin GDF8, TGF-beta muscle peptide, myostatin peptide research
Research context
The myostatin pathway has been one of the most actively studied targets in muscle biology research since Lee and McPherron's foundational 1997 publication in Nature identifying MSTN as the muscle-mass negative regulator. In the two decades since, preclinical research using genetic knockouts, anti-myostatin antibodies, dominant-negative receptor constructs, and follistatin overexpression has consistently demonstrated that myostatin inhibition increases skeletal muscle mass and reduces fat mass in rodent models. Translation to therapeutic contexts has been explored for Duchenne muscular dystrophy, spinal muscular atrophy, cachexia, and sarcopenia; several anti-myostatin antibody programs (stamulumab, domagrozumab, landogrozumab) have reached clinical trials, with mixed results. Follistatin 344 gene therapy (AAV-mediated FST344 overexpression) has been studied in clinical trials for Becker muscular dystrophy and FSHD with published open-label Phase I data.
Follistatin 344 protein as a research compound occupies a distinct niche from AAV gene therapy: it is used in vitro as a recombinant protein to antagonize myostatin (and other TGF-β family members, including activin A and BMP-9) in cell culture, enabling researchers to dissect pathway-specific effects on myoblast differentiation, satellite cell proliferation, and protein synthesis rates. In myotube models, FST344 treatment typically increases myotube diameter (hypertrophy index) and upregulates MyoD and myogenin — master transcription factors for myogenic differentiation. Researchers using FST344 should note its pleiotropic activity: follistatin binds multiple TGF-β family members, so specificity controls (anti-myostatin antibody vs. FST344) are important for attributing effects specifically to myostatin inhibition vs. activin/BMP pathway effects.
For researchers entering the myostatin-inhibitor space: the field distinguishes between myostatin propeptide (the N-terminal fragment that naturally latency-binds myostatin after cleavage), follistatin isoforms (FST288 higher-affinity but cell-surface-bound; FST344 diffusible, the primary circulating form), and pharmacological anti-myostatin antibodies (clinical candidates). DMV Research supplies Follistatin 344 as a recombinant glycoprotein for in-vitro research — purity ≥95% by SDS-PAGE, activity verified in myoblast differentiation assay, COA included. Myostatin itself (GDF-8) is also available as a recombinant protein for assay development and pathway studies. All compounds are research use only with no approved therapeutic claim.
Frequently asked questions
What is myostatin and why is it a research target?+
Myostatin (GDF-8) is a TGF-β superfamily cytokine secreted by skeletal muscle that inhibits muscle growth by suppressing satellite cell activation and protein synthesis via ActRIIB/SMAD2-3 signaling. It is studied because loss-of-function mutations produce extraordinary muscle mass in multiple species (Belgian Blue cattle, whippets, some humans), and inhibiting the pathway is explored in models of muscular dystrophy, cachexia, and sarcopenia. Research use only.
How does Follistatin 344 inhibit myostatin?+
Follistatin 344 (FST344) is a secreted glycoprotein that binds myostatin with high affinity (Kd ~0.5 nM), sterically blocking myostatin's interaction with the ActRIIB receptor. It also binds activin A and certain BMPs, so FST344 inhibition is not myostatin-specific. In myotube cultures, FST344 treatment increases myotube diameter and upregulates MyoD/myogenin expression. Research use only.
What is the difference between Follistatin 344 and Follistatin 288?+
Follistatin 288 (FST288, 288 amino acids) has higher binding affinity for heparan sulfate proteoglycans and tends to be cell-surface-anchored, with expression concentrated in Sertoli cells. Follistatin 344 (FST344, 344 amino acids; the additional 56 residues encode an acidic C-terminal tail that prevents proteoglycan binding) is the diffusible, systemic isoform and the primary circulating form. For muscle biology research, FST344 is the more commonly used isoform as it acts in a paracrine/endocrine manner. Research use only.
What research has studied myostatin inhibition in muscle wasting diseases?+
Multiple clinical programs have tested anti-myostatin strategies: AAV-mediated FST344 gene therapy has Phase I published data in Becker MD and FSHD. Anti-myostatin antibodies (stamulumab, domagrozumab, landogrozumab) have completed Phase I/II trials in DMD, sarcopenia, and cachexia with variable efficacy outcomes. The field consensus is that myostatin inhibition alone produces meaningful muscle mass increases but modest functional gains in disease states, suggesting combination approaches may be needed. Research use only.
Research use only
All products are intended for laboratory and research use only (RUO) and are not for human consumption, ingestion, or any in-vivo use.
The statements on this page have not been evaluated by the FDA. Myostatin Inhibitor Peptides — Follistatin & Muscle Research Hub is not intended to diagnose, treat, cure, or prevent any disease. Content is provided for laboratory research reference only.