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Follistatin 344 Guide: Available Now
Educational use only — not medical advice. This guide summarizes information reported in published research and community practice for educational purposes. It is not medical advice and not a recommendation to use any compound. Any doses, schedules, or combinations shown are examples of what has been reported, not instructions for you. Many peptides described here are research compounds that are not FDA-approved for the uses discussed and may be investigational or restricted. Effects, risks, and legal status vary; individual needs and results vary. Consult a qualified, licensed healthcare professional before making any decision. Do not use this content to diagnose, treat, or dose yourself.
Follistatin 344 at a glance
What it is
A 344-amino-acid recombinant form of the follistatin glycoprotein that binds and neutralizes myostatin and activin
Researched for
Muscle wasting, myostatin inhibition and muscle hypertrophy in preclinical and gene-therapy research contexts
Commonly reported range
Community-reported examples of ~100-300 mcg per administration (not a recommendation)
Route reported
Subcutaneous injection reported in research contexts
Reported frequency
Daily or several times weekly reported, owing to a short circulating half-life
Reported cycle
Short cycles of ~10-30 days followed by time off are commonly described
Plasma half-life
Short; roughly 90 minutes to a few hours reported for the circulating peptide in animal models
Regulatory status
Not FDA-approved; research-use only; WADA-prohibited (S4, hormone and metabolic modulators)
Reported ranges from research/community — examples, not recommendations.
What it is / mechanism
Follistatin 344 (FS-344) is a recombinant form of the naturally occurring follistatin glycoprotein. It acts primarily as a high-affinity binding protein that neutralizes members of the TGF-beta superfamily, most notably myostatin (GDF-8) and activin A. Myostatin normally limits skeletal muscle growth by signaling through activin type II receptors (ActRIIB), so by sequestering myostatin, follistatin is reported in research to release this natural brake on muscle development. After administration, FS-344 is described in the literature as being processed in vivo into shorter isoforms, including the circulating FS-315 form (which binds myostatin systemically) and the more tissue-bound FS-288 form (which has higher affinity for activin). These are reported research mechanisms observed largely in cell and animal models, not established effects in humans.
Researched effects
In preclinical and gene-therapy research, follistatin has been associated with increased skeletal muscle mass, greater muscle fiber size and reported strength gains in animal models, along with interest in counteracting muscle wasting. These are research findings, not guaranteed outcomes, and results reported for gene-delivery studies do not necessarily translate to injectable peptide use, where human data are very limited.
Evidence & regulatory status
Evidence: Most supportive data come from animal studies and gene-therapy research (e.g., primate and muscular-dystrophy models) showing muscle hypertrophy; direct evidence for injectable FS-344 peptide in humans is very limited.
Regulatory: Follistatin 344 is not approved by the FDA for any use and is not a medicine; it is handled as a research chemical. It is prohibited by WADA under class S4 (hormone and metabolic modulators) for competitive athletes.
Research-use: All information here describes what is reported in studies and the research community as examples for educational purposes, not personalized recommendations or evidence of efficacy or safety.
Dosage — reported ranges (overview)
The following are examples of what is reported in the research community, not a recommendation and not a personal dose. Reported protocols commonly describe subcutaneous administration in the range of roughly 100-300 mcg, given daily or several times per week because the circulating peptide has a short half-life. Short cycles of about 10-30 days followed by time off are frequently described. Because human safety and dosing data are minimal, these figures are illustrative only and should not be interpreted as guidance for use.
The full step-by-step protocol examples, titration, and printable protocol sheet are planned for a future paid Protocol Playbook module.
Reconstitution — bac-water math
Follistatin 344 is dosed in micrograms (mcg), so reconstitution is a concentration calculation. Using a U-100 insulin syringe (100 units = 1 mL), concentration in mcg/mL equals the total peptide in the vial divided by the milliliters of bacteriostatic water added, and the units to draw equal the desired dose divided by that concentration, times 100. Worked example: a 1 mg (1,000 mcg) vial reconstituted with 2 mL of bacteriostatic water gives 1,000 / 2 = 500 mcg/mL. A 100 mcg example dose is then 100 / 500 x 100 = 20 units on a U-100 syringe. This is concentration math only, not a personal dose.
Bac water added
Concentration
100 mcg
200 mcg
1 mL
1,000 mcg/mL
10 units (0.10 mL)
20 units (0.20 mL)
2 mL
500 mcg/mL
20 units (0.20 mL)
40 units (0.40 mL)
3 mL
333 mcg/mL
30 units (0.30 mL)
60 units (0.60 mL)
This is concentration math, not a dose recommendation.
Pre-fills example values. Every field remains editable.
The amount printed on the vial or listed on a product page.
mL
Liquid volume used for the concentration calculation.
The mass amount to convert into liquid volume for this math example.
4. Insulin syringe size
Your result
Syringe-unit reading
10 units
= 0.1 mL · 250 mcg target amount
Concentration
2.5mg/mL
Per insulin unit
25mcg
Portions per vial
20
Volume
0.1mL
This calculator is an educational tool for laboratory and research math only. The peptides referenced are research compounds not intended for human or veterinary use, and example values are not medical advice or personal-use instructions. Follow applicable research protocols and regulations.
How the calculator works
Concentration
peptide ÷ liquid
Total peptide divided by liquid volume gives the concentration per mL.
Volume
target ÷ concentration
The target mass divided by concentration gives the liquid volume.
Syringe units
volume × 100
For insulin units, 100 units equals 1 mL, so mL is multiplied by 100.
Worked example: A 5 mg vial plus 2 mL liquid creates a 2.5 mg/mL concentration. A 250 mcg target amount equals 0.1 mL, or 10 insulin units. The vial contains 20 such portions.
Frequently asked questions
How much bacteriostatic water should I enter?+
There is no single calculator-default amount. The liquid volume controls concentration: more liquid creates a less concentrated solution and a larger volume reading for the same target amount; less liquid creates a more concentrated solution and a smaller volume reading.
How do insulin syringe units relate to mL?+
For this math tool, 100 insulin units equals 1 mL, and 1 unit equals 0.01 mL. The 0.3 mL, 0.5 mL, and 1.0 mL options change capacity, not the unit-to-mL relationship.
What is the difference between mg, mcg, and units?+
Milligrams and micrograms measure peptide mass: 1 mg = 1,000 mcg. Syringe units measure liquid volume. Reconstitution math connects mass and volume by using concentration.
Does changing the liquid volume change the total peptide in the vial?+
No. The total peptide amount entered for the vial remains fixed. Changing the liquid volume only changes concentration and the resulting volume shown by the calculator.
Injection / administration basics
In research contexts, follistatin 344 is reported to be administered by subcutaneous injection using a small-gauge insulin syringe, drawing the calculated number of units after reconstitution. Bacteriostatic water is typically used to reconstitute the lyophilized powder, adding it slowly against the vial wall and gently swirling rather than shaking. General aseptic handling (cleaning the vial stopper and injection site) is described in the research literature. None of this constitutes medical instruction for human use.
Half-life & frequency rationale
The circulating follistatin 344 peptide is reported to have a short half-life, with animal-model estimates ranging from roughly 90 minutes to a few hours. Tissue binding, particularly in skeletal muscle, is described as extending the biological effect window somewhat, but the short plasma half-life is the reason frequent (often daily) dosing appears in reported protocols.
Side effects, safety & contraindications
Human safety data for injectable follistatin 344 are very limited, so its side-effect profile is not well characterized. Community-reported effects include injection-site irritation, mild fatigue and transient joint stiffness. Because follistatin also binds activin, which has roles beyond muscle (including in reproductive and other tissues), there is theoretical concern about broader systemic effects and unstudied long-term risks. The absence of controlled human studies means potential adverse effects may be underreported.
Stacking — overview
In the research community, follistatin 344 is often described alongside anabolic and growth-signaling peptides, on the rationale that myostatin inhibition removes a growth ceiling while other compounds stimulate growth directly. These are reported pairings for educational context, not recommendations, and stacking is described as increasing the potential for compounded, poorly characterized effects.
Growth factor stack
Follistatin 344 + IGF-1 LR3 + MGF
GH secretagogue pairing
Follistatin 344 + CJC-1295 + Ipamorelin
Recovery and repair
Follistatin 344 + BPC-157 + TB-500
Muscle-signaling combo
Follistatin 344 + GHRP-2
Storage & handling
Lyophilized (unreconstituted) powder is reported to be stable refrigerated and can be kept frozen for longer-term storage; keep it away from light and moisture.
Once reconstituted with bacteriostatic water, it is typically stored refrigerated (about 2-8 C) and used within a few weeks, avoiding freezing and repeated temperature swings.
References
Information is compiled from published preclinical and gene-therapy literature on follistatin and myostatin inhibition, WADA Prohibited List documentation, and peptide research-community sources, and is provided for educational purposes only.
Related peptide guides
Continue exploring related educational guide topics in the Medibact library.
Quick answers about guide scope, access, and educational use context.
What is the difference between Follistatin 344 and FS-315?
Follistatin 344 (FS-344) is the 344-amino-acid form often used in research; it is described as being processed in the body into shorter isoforms including the circulating FS-315 form, which binds myostatin systemically, and the tissue-bound FS-288 form. This is reported research context, not medical advice.
Is Follistatin 344 approved or legal to use?
No. It is not FDA-approved for any use and is handled as a research chemical. It is also prohibited by WADA for competitive athletes. This guide is educational only and does not endorse human use.
Why is it dosed so frequently in reported protocols?
The circulating peptide has a short half-life (reported as roughly 90 minutes to a few hours in animal models), which is why reported research protocols often describe daily or several-times-weekly administration. This is a description of reported practice, not a recommendation.
How is a research dose calculated after reconstitution?
Concentration in mcg/mL equals the vial's total mcg divided by the mL of bacteriostatic water added. Units to draw on a U-100 syringe equal the target mcg divided by that concentration, times 100. For example, a 1 mg vial in 2 mL gives 500 mcg/mL, so 100 mcg is 20 units. This is concentration math, not a personal dose.
Does follistatin 344 build muscle in humans?
Most supportive evidence comes from animal and gene-therapy studies, not injectable peptide use in humans, where data are very limited. Reported muscle effects are research findings, not guaranteed or proven outcomes in people.
Compliance and trust notes
Educational content only; no personalized health or outcome claims.
No personalized use recommendation outputs.
Use this material for general learning and research-context literacy.
Educational use only — not medical advice. This guide summarizes information reported in published research and community practice for educational purposes. It is not medical advice and not a recommendation to use any compound. Any doses, schedules, or combinations shown are examples of what has been reported, not instructions for you. Many peptides described here are research compounds that are not FDA-approved for the uses discussed and may be investigational or restricted. Effects, risks, and legal status vary; individual needs and results vary. Consult a qualified, licensed healthcare professional before making any decision. Do not use this content to diagnose, treat, or dose yourself.
