Follistatin 344
✅ 344-aa recombinant glycoprotein
✅ Myostatin & activin pathway antagonist
✅ Muscle hypertrophy research compound
✅ Muscular dystrophy preclinical models
✅ ≥95% HPLC purity, COA on request
Follistatin 344 is a recombinant protein.
✓ Medisch beoordeeld door Morgan Ellis — Apotheekonderzoeker · 8 jaar ervaring · Laatst beoordeeld: mei 2026
Quick Answer — What is Follistatin 344?
Follistatin 344 (FST-344) is a 344-amino-acid recombinant glycoprotein and the longer of the two principal splice isoforms of human follistatin. It is the canonical endogenous antagonist of myostatin (GDF-8) and activin, used in published research investigating muscle hypertrophy, sarcopenia, muscular dystrophy preclinical models, and the activin/myostatin signalling axis. Supplied in 1 mg lyophilized vials for laboratory research use only.
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| Specificatie | Detail |
|---|---|
| CAS-nummer | 80449-31-6 (follistatin) |
| Type | Recombinant glycoprotein (344-amino-acid FST-344 splice isoform of human follistatin) |
| Moleculair gewicht | ~37 kDa (mature glycosylated form; ~38–42 kDa observed range on SDS-PAGE depending on glycosylation state) |
| Structure | N-terminal heparin-binding domain followed by three follistatin domains (FSD1, FSD2, FSD3) each containing an EGF-like and a Kazal-like subdomain; cysteine-rich, multiple intramolecular disulfide bonds |
| Form | Lyophilized recombinant protein (white to off-white) |
| Zuiverheid | ≥95% (HPLC verified, COA on request) |
| Opslag | Lyophilized: 2–8 °C (refrigerator) for working stock; −20 °C for long-term storage of unopened vials. Reconstituted: 2–8 °C, use within ~30 days. Protect from light. Do not freeze–thaw the reconstituted solution — recombinant proteins are particularly sensitive to freeze-thaw denaturation. |
| Oplosbaarheid | Bacteriostatic water (recommended) or sterile water for shorter use windows. Carrier protein (BSA, 0.1%) optional for working dilutions to minimise adsorption losses. |
| Onderzoeksgebruik | Alleen voor laboratoriumonderzoek. Niet voor humaan of veterinair diagnostisch of therapeutisch gebruik. |
What Is Follistatin 344?
Follistatin 344 (often abbreviated FST-344) is a recombinant 344-amino-acid glycoprotein and the longer of the two principal physiological splice isoforms of human follistatin — the other being FST-288, a shorter 288-amino-acid membrane-bound form. Endogenous follistatin was first isolated in 1987 from porcine ovarian follicular fluid by Esch et al. (PNAS) and Robertson et al. (Biochem Biophys Res Commun) as a factor that selectively inhibits follicle-stimulating hormone (FSH) secretion, which gave the protein its name. The mechanistic role — high-affinity binding and neutralisation of activin and myostatin — was characterised over the subsequent decade.
FST-344 is a circulating, secreted isoform with a heparin-binding N-terminal domain followed by three cysteine-rich follistatin domains (FSD1, FSD2, FSD3) that together form the activin- and myostatin-binding surface. The recombinant 344-residue chain has a mature mass of approximately 37 kDa, with apparent molecular weight on SDS-PAGE varying between 38 and 42 kDa depending on the glycosylation state of the recombinant expression system. CAS number 80449-31-6. The protein is supplied as a high-purity lyophilized powder for reconstitution with bacteriostatic water. Follistatin is not approved by the FDA, EMA, MHRA, or any other major regulator for human therapeutic use. The research-grade follistatin 344 sold here is supplied uitsluitend voor laboratoriumonderzoek and is not intended for human or veterinary administration. For related anabolic and growth-axis research, see our IGF-1 LR3 product page.
Mechanism of Action — Myostatin and Activin Pathway Antagonism
What makes follistatin 344 mechanistically unique among muscle-research proteins is its multi-target binding profile across the TGF-β superfamily — each ligand-binding event contributing to the observed hypertrophic and growth-modulatory phenotype in published research:
- Myostatin (GDF-8) sequestration — muscle hypertrophy axis — Follistatin binds myostatin (also called GDF-8) with high affinity, sterically blocking its interaction with the activin type II receptor (ActRIIB). Myostatin is the canonical endogenous negative regulator of muscle growth: knockout mice develop dramatic muscle hypertrophy (the “double-muscling” phenotype), and naturally myostatin-deficient cattle breeds (Belgian Blue, Piedmontese) show the same effect. By neutralising myostatin, follistatin removes the brake on muscle protein synthesis, producing hypertrophy in research models. This is the most-cited mechanism in the muscle-research literature.
- Activin A and B sequestration — reproductive, ovarian, and pituitary signalling — Follistatin’s original characterised function was binding and neutralising activin, a related TGF-β superfamily member that stimulates FSH secretion from the pituitary, drives ovarian follicle development, and acts as a regulator of many cell types. By binding activin A, B, and AB heterodimers, follistatin shifts the activin/inhibin balance in research models and modulates downstream Smad2/Smad3 signalling.
- GDF-11 and broader TGF-β superfamily modulation — Follistatin also binds GDF-11 (closely related to myostatin) with somewhat lower affinity, alongside other TGF-β superfamily members. GDF-11 is increasingly studied in aging research because its endogenous levels decline with age and its modulation is implicated in age-related cardiac and CNS phenotypes. Follistatin 344 is one of the principal research tools for investigating this axis.
The three follistatin domains (FSD1, FSD2, FSD3) each contribute to the binding profile: FSD1 contains the principal myostatin-binding surface, FSD2 the principal activin-binding surface, and FSD3 contributes both binding affinity and structural stability. The heparin-binding N-terminal domain distinguishes the splice variants — FST-288 binds heparan sulfate strongly and is largely membrane-anchored, while FST-344 (this isoform) circulates more freely. This distinction is mechanistically relevant in research models studying systemic vs local follistatin effects.
Published Research Applications
Follistatin 344 is used in laboratory research contexts that investigate:
- Muscle hypertrophy and protein synthesis research — mouse and rat hypertrophy models including AAV-follistatin gene-delivery studies (Kota et al., Sci Transl Med 2009); fibre-type-specific cross-sectional area, muscle wet weight, force-generation
- Muscular dystrophy preclinical models — mdx mouse model of Duchenne muscular dystrophy; functional capacity, fibre regeneration, dystrophin-independent muscle preservation
- Sarcopenia and age-related muscle loss — aged-mouse muscle phenotypes, anabolic resistance, fibre-type-shift research
- Cancer cachexia research — cachexia models in tumour-bearing mice, body composition preservation, lean mass / fat mass ratio
- Reproductive endocrinology research — FSH suppression, ovarian follicle development, granulosa-cell biology, pituitary-gonadal-axis research
- Activin pathway research — Smad2/Smad3 signalling, EMT in cancer models, fibrosis research, hepatic regeneration
- Aging and GDF-11 axis research — cardiac and CNS aging phenotypes, parabiosis-related research, GDF-11/myostatin balance with aging
- Comparative anabolic research — head-to-head with IGF-1 LR3 (parallel anabolic pathway via IGF-1 receptor) for combined or comparative hypertrophy research.
For broader context on where follistatin 344 fits within the anabolic and growth-axis research landscape, see IGF-1 LR3 as the canonical IGF-axis comparator, CJC-1295 met DAC for GHRH-axis growth research, and Sermorelin for shorter-acting GHRH research. Browse the full onderzoekspeptiden catalogus voor gerelateerde verbindingen.
Beschikbare sterktes en concentraties
MedsBase stocks Follistatin 344 in 1 mg lyophilized vials. The vial is available in 10-vial or 20-vial pack formats with full reconstitution guidance:
| Vulsterkte | Typical Research Use Case | Verpakkingsgroottes |
|---|---|---|
| 1 mg | Standard research strength — muscle hypertrophy and activin/myostatin axis research | 10 of 20 flesjes |
Follistatin 344 is a 37 kDa recombinant glycoprotein supplied at ≥95% HPLC purity. The 1 mg vial format is the standard research strength for in vivo and in vitro work — one vial reconstituted with 1.0 mL bacteriostatic water yields a 1 mg/mL working concentration sufficient for many weeks of cell-culture protocols or several rodent-protocol injections.
How It Compares — Follistatin 344 vs IGF-1 LR3
Follistatin 344 and IGF-1 LR3 are the two most-cited recombinant anabolic proteins in current hypertrophy research. They act on entirely different pathways — follistatin by removing the myostatin brake on muscle growth, IGF-1 LR3 by directly stimulating the IGF-1 receptor and downstream Akt/mTOR protein synthesis — which makes them mechanistically complementary in research protocols.
| Criterium | Follistatin 344 | IGF-1 LR3 |
|---|---|---|
| Length | 344 amino acids (recombinant glycoprotein) | 83 amino acids (modified IGF-1) |
| Molecular weight | ~37 kDa | ~9 kDa |
| Primary mechanism | Myostatin / activin sequestration | IGF-1 receptor agonism → Akt/mTOR |
| Effect mode | Disinhibition (removes growth brake) | Direct anabolic stimulation |
| Typical research dose | 10–100 mcg, 1–3x weekly | 20–60 mcg, daily |
| Strongest research signal | Whole-muscle hypertrophy, dystrophy models | Local hypertrophy, regenerative anabolic research |
| Stacking | Commonly co-administered with IGF-1 LR3 in hypertrophy research | Commonly co-administered with follistatin 344 |
Because the two proteins act on fundamentally different anabolic axes — follistatin removes the myostatin brake while IGF-1 LR3 directly stimulates protein synthesis — combined administration is commonly used in research models exploring maximal hypertrophic response. For research interested in the myostatin pathway specifically, follistatin 344 is the canonical first choice; for IGF/Akt/mTOR anabolic research, IGF-1 LR3 is the canonical research tool.
Opslag en Reconstituering
Voor reconstituering: store lyophilized vials refrigerated at 2–8 °C in original packaging for short-term working stock. For unopened long-term storage, freeze at −20 °C. Lyophilized follistatin 344 is stable under refrigeration for up to 12 months and at −20 °C for up to 24 months — somewhat shorter than small synthetic peptides because the larger recombinant glycoprotein is more susceptible to deamidation and oxidation over time. Avoid freeze-thaw cycles on the lyophilized powder.
Reconstitueringsprocedure: inject bacteriostatic water down the side wall of the peptide vial (not directly onto the lyophilized cake). For a 1 mg vial, 1.0 mL of bacteriostatic water yields a 1 mg/mL working concentration. Swirl gently — do niet shake — and allow 5–10 minutes for full dissolution. Recombinant proteins dissolve more slowly than small peptides; do not rush the dissolution step. A correctly reconstituted solution should be clear and colourless with no visible particles. For working dilutions below 100 mcg/mL, the addition of carrier protein (BSA at 0.1% final concentration) minimises adsorption losses to plastic and glass.
Na reconstitutie: store refrigerated at 2–8 °C and use within 30 days for optimal stability. Do not freeze the reconstituted solution — recombinant glycoproteins are particularly sensitive to freeze-thaw denaturation, which produces aggregation and loss of activity. Discard any vial showing cloudiness, precipitate, or discolouration.
Veelgestelde vragen
What is Follistatin 344 used for in research?
Follistatin 344 is used in laboratory research investigating muscle hypertrophy, muscular dystrophy preclinical models, sarcopenia, cancer cachexia, the activin/myostatin/GDF-11 signalling axis, reproductive endocrinology (FSH suppression, ovarian follicle development), and aging-related phenotypes. It is the canonical research tool for myostatin pathway antagonism. The research-grade follistatin 344 sold here is niet FDA-approved and is supplied strictly for laboratory research use only.
What is the difference between Follistatin 344 and Follistatin 315?
FST-344 is the gene-product 344-amino-acid isoform including the signal peptide; FST-315 is the same protein after signal-peptide cleavage during secretion (so FST-315 is the mature circulating form of FST-344). Both nomenclature systems appear in the literature and refer to the same biological isoform. Both differ substantially from FST-288, which is a shorter alternatively-spliced isoform with stronger heparan-sulfate binding and largely membrane-bound localisation.
How is Follistatin 344 different from IGF-1 LR3?
Both are recombinant anabolic proteins used in muscle hypertrophy research, but they target different pathways. Follistatin 344 is a 344-amino-acid glycoprotein that binds and sequesters myostatin and activin — it works by removing the endogenous brake on muscle growth. IGF-1 LR3 is an 83-amino-acid modified IGF-1 analog that directly agonises the IGF-1 receptor and activates Akt/mTOR protein synthesis. The two are mechanistically complementary and frequently co-administered in research.
What is the typical Follistatin 344 research dose?
Published preclinical protocols typically use 10–100 mcg per administration in rodent models, given 1–3 times weekly for 4–12 week cycles. Gene-delivery research using AAV-follistatin produces tissue-localised concentrations that are difficult to compare directly to systemic-protein dosing. A 1 mg vial reconstituted with 1.0 mL bacteriostatic water yields 1 mg/mL — 0.01 mL equals 10 mcg, 0.1 mL equals 100 mcg.
Is Follistatin 344 FDA approved?
No. Follistatin 344 is not approved by the FDA, EMA, MHRA, or any other major regulator for human therapeutic use. AAV-follistatin gene therapy has been investigated in clinical trials for muscular dystrophy (e.g., Becker muscular dystrophy, inclusion body myositis) but is not FDA-approved. All follistatin 344 sold by research-use-only suppliers is for laboratory investigation and should not be administered to humans.
How should Follistatin 344 be stored?
Lyophilized vials: refrigerated at 2–8 °C for short-term working stock, or −20 °C for long-term storage of unopened vials. Reconstituted solution: refrigerated at 2–8 °C, use within 30 days. Do not freeze reconstituted solution — recombinant glycoproteins are particularly sensitive to freeze-thaw denaturation. Protect from direct light at all times. Carrier protein (BSA at 0.1%) is recommended for working dilutions below 100 mcg/mL.
How do I reconstitute Follistatin 344?
Follow the reconstitution procedure above. Add bacteriostatic water down the side wall of the vial (not onto the lyophilized cake), swirl gently, and allow 5–10 minutes for full dissolution. Do niet shake the vial — vigorous agitation can denature recombinant proteins and cause aggregation. A correctly reconstituted solution is clear and colourless. For a 1 mg vial + 1.0 mL diluent, the working concentration is 1 mg/mL.
Why is the purity specification 95% rather than 99%?
Recombinant glycoproteins like follistatin 344 cannot achieve the ≥99% HPLC purity standard typical of small synthetic peptides because of the inherent heterogeneity of glycosylation in any recombinant expression system — different glycoforms appear as related peaks on HPLC that are not impurities but isoforms of the target protein. ≥95% HPLC purity is the standard research-grade specification for follistatin 344 and similar recombinant glycoproteins. SDS-PAGE typically shows a single band with the expected 38–42 kDa apparent mass range.
Welke sterktes heeft MedsBase op voorraad?
MedsBase carries Follistatin 344 in 1 mg lyophilized vials. The vial is available in 10-vial or 20-vial pack sizes. All vials are supplied at ≥95% HPLC purity with a certificate of analysis available on request.
Can Follistatin 344 and IGF-1 LR3 be stacked in research?
Yes. Follistatin 344 and IGF-1 LR3 act on fundamentally different anabolic axes (myostatin antagonism vs IGF-1 receptor agonism) and are frequently co-administered in research models exploring maximal hypertrophic response. The two are mechanistically complementary rather than redundant, and combined-protocol literature describes additive or synergistic effects on muscle fibre cross-sectional area.
Does Follistatin 344 cause side effects in research?
Published preclinical research has documented tolerability at typical research doses, with the main on-target effect being muscle hypertrophy. Off-target findings include modulation of FSH and ovarian function (because activin signalling is suppressed) and potential effects on hepatic regeneration and pituitary regulation due to follistatin’s role in broader TGF-β superfamily signalling. Systemic follistatin-protein dosing has different exposure characteristics than tissue-localised AAV-gene-delivery approaches.
What is the half-life of Follistatin 344?
In preclinical research, recombinant follistatin 344 has a plasma half-life of approximately 1–3 hours following intravenous administration, reflecting its size (37 kDa, above the renal filtration cutoff) and binding to circulating ligands. Tissue half-life is considerably longer because follistatin remains bound to its captured myostatin and activin targets, sequestering them away from receptors. Gene-delivery approaches produce a far longer effective duration of action because tissue expression continues over weeks to months.
How long does Follistatin 344 take to show effects in preclinical research?
Muscle hypertrophy effects in mouse and rat protein-injection protocols typically become statistically significant after 2–4 weeks of weekly dosing and continue to accrue through 8–12 weeks. Activin / FSH-axis effects on reproductive endpoints can be detected within days of administration. Gene-delivery (AAV-follistatin) protocols show measurable muscle hypertrophy by 4–6 weeks post-injection and continue to develop over months.
Can I order Follistatin 344 for international shipping?
Yes. MedsBase ships Follistatin 344 worldwide from our dedicated peptide shipping network. Peptide-only orders qualify for our standalone peptide shipping service. All orders ship in temperature-controlled packaging with full tracking and are covered by our Reshipment Assurance Policy.
Other Peptides for Anabolic, Growth-Axis, and Muscle Research
- IGF-1 LR3 — Long-arginine recombinant IGF-1 analog — direct IGF-1R agonist for Akt/mTOR research
- CJC-1295 met DAC — Long-acting GHRH analog — growth hormone axis research
- Sermorelin — Shorter-acting GHRH(1-29) analog — natural GH-pulse research
- Ipamorelin — Selectieve ghreline-agonist — schone GH-puls zonder cortisol/prolactine
- TB-500 (Thymosin Beta-4) — Systemic healing fragment — muscle and cardiac recovery research
Verder lezen
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Bekijk het volledige onderzoekspeptiden catalogus, with related compounds including IGF-1 LR3 for direct IGF-receptor anabolic research, CJC-1295 met DAC for long-acting GHRH research, and TB-500 for systemic muscle and tissue recovery research.
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| Sterkte | 1 mg |
|---|---|
| Hoeveelheid | 10 flacons, 20 flacons, 30 flacons |
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