Principal investigators seeking to order follistatin for in vitro assays or preclinical animal models require verified analytical purity, low endotoxin levels, and full lot-specific traceability. PX1 Research provides USA-manufactured, RP-HPLC and mass spectrometry-certified Follistatin designed strictly for scientific research environments.
Principal investigators seeking to order follistatin for in vitro assays or preclinical animal models require verified analytical purity, low endotoxin levels, and full lot-specific traceability. PX1 Research provides USA-manufactured, RP-HPLC and mass spectrometry-certified Follistatin designed strictly for scientific research environments.
To order follistatin for qualified laboratory research, academic and institutional buyers must ensure that compounds meet rigorous biochemical benchmarks. Follistatin (FST) is a complex autocrine glycoprotein that functions primarily as an antagonist to members of the Transforming Growth Factor-beta (TGF-β) superfamily. Because recombinant protein production can introduce post-translational variability and bacterial endotoxins, acquiring research-grade material requires verified sourcing from facilities adhering to standard Good Manufacturing Practice (GMP) guidelines.
PX1 Research synthesizes and distributes USA-manufactured Follistatin variants specifically formatted for non-clinical analytical environments. Every lot undergoes independent analytical testing to confirm primary sequence identity, purity via reversed-phase high-performance liquid chromatography (RP-HPLC), and mass determination via electrospray ionization mass spectrometry (ESI-MS). Investigators looking to expand their laboratory inventory can review our complete catalog of research peptides to coordinate bulk compound acquisition alongside our verified Follistatin offerings.
Follistatin naturally exists in several distinct isoforms generated via alternative splicing and post-translational proteolysis of the single *FST* gene. The primary precursor molecule, Follistatin 344 (FST-344), contains 344 amino acids. Upon enzymatic cleavage, the C-terminal region is removed to yield the circulating isoform, Follistatin 315 (FST-315), or the highly heparin-reactive tissue-bound variant, Follistatin 288 (FST-288). Structural characterization shows that all isoforms contain three conserved domain repeats (FS1, FS2, and FS3) that physically encapsulate ligand molecules.
In experimental models, the functional differences between isoforms dictate tissue localization and systemic clearance rates. For example, Follistatin-344 peptide is widely referenced in preclinical gene-delivery and recombinant protein studies due to its broad expression profile, whereas Follistatin-315 exhibits longer systemic half-life in fluid assays owing to lower binding affinity for cell-surface heparin sulfate proteoglycans. Understanding these isoform-specific attributes is critical when establishing primary end-point criteria for downstream cellular assays.
The primary mechanism of action for Follistatin centers on its ability to bi-physically bind and neutralize specific TGF-β family ligands, most notably Myostatin (Growth Differentiation Factor 8 / GDF-8) and Activin A. Under baseline physiological conditions, Activin A and Myostatin engage the Activin Type IIB receptor (ActRIIB) complex on cell membranes, triggering downstream phosphorylation of Smad2 and Smad3 transcription factors. This signaling cascade upregulates genes responsible for protein degradation while inhibiting protein synthesis pathways governed by Akt/mTOR.
When introduced into cell cultures or animal models, Follistatin binds to Myostatin and Activin with nanomolar to picomolar affinity. This binding event physically buries the receptor-interacting epitopes of the growth factors, preventing them from docking onto ActRIIB. As a result, intracellular Smad2/3 phosphorylation is attenuated, providing researchers a robust tool to investigate baseline intracellular signaling, satellite cell activation mechanisms, and downstream transcription changes in target tissues. Researchers studying upstream cytokine signaling pathways can cross-reference these findings in our PX1 research repository.
In vitro data indicate that incubation of skeletal muscle myoblasts with recombinant Follistatin results in a dose-dependent reduction of Smad-responsive reporter gene activity. In C2C12 myotube cultures, exposure to Follistatin blunts the catabolic response induced by exogenous myostatin, promoting augmented myotube diameter and elevated protein retention markers. Furthermore, cellular assays demonstrate that Follistatin blunts Activin-mediated secretion of follicle-stimulating hormone (FSH) in pituitary cell lines, illustrating its multi-systemic regulatory roles.
In vivo rodent models further corroborate these cellular mechanisms. Preclinical trials utilizing vector-mediated gene transfer of Follistatin or continuous administration of recombinant peptide have demonstrated marked increases in lean muscle mass, cross-sectional muscle fiber area, and force production capabilities in both wild-type mice and models of muscular dystrophy. In non-human primate research, localized delivery of Follistatin constructs resulted in significant, sustained increases in muscle size without systemic organ toxicity, reinforcing its utility as a benchmark research tool for therapeutic vector development.
When designing protocols targeting the myostatin/activin pathway, researchers frequently evaluate Follistatin against alternative candidates within the broader class of myostatin inhibitor compounds. While Follistatin offers dual-antagonism against both Activin A and Myostatin, target-specific agents such as GDF-8 monoclonal antibodies selectively isolate myostatin without altering activin-mediated reproductive or inflammatory axis signaling. Selecting the ideal compound depends heavily on whether the protocol aims to evaluate global ActRIIB pathway suppression or target-isolated ligand neutralization.
Similarly, soluble receptor decoys such as ActRIIB-Fc fusion proteins bind a broader spectrum of TGF-β family members—including BMP-9 and BMP-10—which can alter vascular physiology in animal models. Follistatin exhibits a more restricted binding profile relative to soluble ActRIIB-Fc molecules, reducing unwanted cross-reactivity in multi-tissue organoid cultures. For comparative research involving broader anabolic signaling cascades, investigators often benchmark Follistatin alongside downstream cellular peptides detailed in our overview of TGF-beta pathway modulators.
Because structural integrity is fundamental to ligand-binding kinetics, sourcing laboratories must insist on rigorous quality control verification prior to running experimental series. Every batch of Follistatin supplied by PX1 Research undergoes rigorous analytical verification conducted in an ISO 17025 accredited testing facility located within the United States. We provide lot-specific Certificates of Analysis (COAs) detailing essential physical and biochemical metrics.
Our analytical verification protocols incorporate two core methodologies: High-Performance Liquid Chromatography (RP-HPLC) to establish chemical purity standards exceeding 98%, and Electrospray Ionization Mass Spectrometry (ESI-MS) to verify precise molecular weight and structural identity. Additionally, because bacterial lipopolysaccharides can alter cytokine profiles and skew baseline cell culture data, our Follistatin undergoes quantitative Limulus Amebocyte Lysate (LAL) testing to confirm endotoxin levels remain below strictly controlled thresholds (<0.1 EU/mg).
To maintain tertiary protein structure and biological potency, research-grade Follistatin lyophilized powder must be stored under controlled thermal conditions upon arrival. Unopened vials should be preserved at -20°C or -80°C for long-term storage, protected from exposure to direct light and ambient humidity. Allow vials to equilibrate to room temperature inside a desiccator chamber prior to reconstitution to prevent moisture condensation on the lyophilized cake.
Reconstitution should be performed using sterile, bacteriostatic water or sterile phosphate-buffered saline (PBS, pH 7.4), depending on the requirements of the downstream assay. Gently swirl or invert the vial until the lyophilized powder is completely dissolved; aggressive vortexing or high-shear agitation should be strictly avoided to prevent mechanical denaturation or peptide aggregation. Reconstituted stock solutions should be aliquoted into single-use polypropylene tubes and stored at -80°C to minimize freeze-thaw cycles. Dilute working solutions immediately prior to conducting in vitro assays or microinjections.
Navigating international peptide supply chains often exposes research institutions to risks associated with batch-to-batch variability, missing analytical documentation, or custom clearance delays. PX1 Research eliminates these vulnerabilities by maintaining full domestic operations. All research compounds are synthesized in state-of-the-art GMP-compliant facilities within the USA and fulfilled directly from our domestic distribution centers in California and Arizona.
By controlling every stage of production—from solid-phase peptide synthesis (SPPS) and chromatographic purification to final lyophilization and packaging—PX1 Research ensures consistent lot-to-lot reproducibility. Every order is dispatched with protective temperature-controlled insulation and full chain-of-custody documentation, ensuring that sensitive reagents arrive at your facility structurally intact and ready for immediate experimental deployment.
PX1 Research works directly with academic university departments, contract research organizations (CROs), and private biotechnology enterprises to streamline supply logistics. Institutional buyers requiring recurring orders or bulk quantities of high-purity Follistatin can set up a dedicated bulk lab procurement account to access custom lot reservations, volume pricing structures, and streamlined purchase order processing.
All products provided by PX1 Research are strictly designated for laboratory research, analytical testing, and in vitro or preclinical animal studies. They are not intended for human or veterinary administration, medical diagnostic procedures, or therapeutic use. By maintaining a rigorous focus on scientific purity and regulatory compliance, PX1 Research remains a trusted operational partner for high-impact biochemical investigation.
What is the purity specification for Follistatin ordered from PX1 Research?
Every lot of Follistatin supplied by PX1 Research is verified via RP-HPLC to meet or exceed 98% purity, with mass identity confirmed by ESI-MS and lot-specific Certificates of Analysis provided.
How is endotoxin content measured for research-grade Follistatin?
Endotoxin levels are quantified using an expanded Limulus Amebocyte Lysate (LAL) chromogenic assay to guarantee levels remain under 0.1 EU/mg, preventing lipopolysaccharide interference in cell cultures.
What is the difference between Follistatin-344 and Follistatin-315 in lab protocols?
Follistatin-344 is the precursor peptide commonly utilized in gene transfer studies, while Follistatin-315 represents the primary circulating isoform with lower heparin affinity, making it suitable for systemic liquid assays.
How should lyophilized Follistatin be stored upon delivery?
Lyophilized Follistatin should be stored at -20°C or -80°C in a dry environment protected from light. Upon reconstitution, aliquot into single-use vials and store at -80°C to prevent freeze-thaw degradation.
Can I obtain a lot-specific Certificate of Analysis before ordering?
Yes. PX1 Research provides downloadable, lot-specific COAs featuring complete RP-HPLC chromatograms and ESI-MS mass spectra directly on product pages or via customer support request.
Where is PX1 Research Follistatin manufactured and shipped from?
All PX1 Research peptides are manufactured in USA-based GMP-compliant facilities and shipped directly from fulfillment nodes in California and Arizona.
What solvent is recommended for reconstituting Follistatin for in vitro assays?
Reconstitution is typically performed using sterile bacteriostatic water or sterile PBS (pH 7.4). Avoid aggressive shaking or vortexing to prevent protein denaturation.
Are PX1 Research compounds approved for clinical or therapeutic use in humans?
No. All products offered by PX1 Research, including Follistatin, are intended strictly for laboratory research, in vitro studies, and preclinical animal models. They are never for human or veterinary use.
All products are sold strictly for laboratory and research use only. Not for human or veterinary use, diagnosis, treatment or consumption. Statements have not been evaluated by the FDA.