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Follistatin 344
Research Use
Also known as FST-344
Function
Primary
Muscle growth · Anti-fibrotic
Secondary
Fertility (research)
Mechanism
Activin/myostatin antagonist — binds and neutralizes myostatin and activin A; promotes satellite-cell activation and muscle hypertrophy; reduces fibrosis.
Evidence
Pre-clinical / Observational
Research
Gene therapy trials ongoing; limited protein-form human data
Dosing
Range
100 mcg/dose (experimental)
Frequency
Variable (research protocols only)
Route
Intramuscular · Subcutaneous
Administration & Technique
Intramuscular (IM)
Used for depot formulations, some GH secretagogues (localized delivery), and clinical protocols requiring faster systemic uptake.
Device23–25G × 1–1.5" needle. 1–3 mL syringe.
TechniqueVentrogluteal, vastus lateralis, or deltoid. Insert 90°, aspirate (optional), inject slowly. Rotate sites weekly.
Subcutaneous (SubQ)
Default route for most research and therapeutic peptides — best absorption for reconstituted powder.
Device31G × 5/16" insulin syringe (U-100). 100 units = 1 mL.
TechniquePinch skin at abdomen (2" from navel), outer thigh, or love handle. Insert at 45–90°. Rotate sites daily to prevent lipohypertrophy. Alcohol-swab site, air-dry, inject slow, hold 5 sec.
Injection & Application Sites
Front
Back
Intramuscular (IM)
- Ventrogluteal — Palm on greater trochanter, index to ASIS — inject in the V. Safest IM site.
- Dorsogluteal (upper outer) — Upper outer quadrant of the buttock. Used for depot IM; alternate sides each cycle.
- Upper arm / deltoid — Back of the upper arm for SubQ; 2 in below the shoulder bone for IM.
- Anterior thigh (vastus lateralis) — Middle third of the outer front thigh. Preferred IM site for self-injection.
Subcutaneous (SubQ)
- Abdomen — 2 in (5 cm) away from the navel, either side. Fastest, most consistent SubQ absorption.
- Flank / love handle — Lateral fat pad above the hip. Good rotation site when the abdomen is tender.
- Outer thigh — Upper outer quadrant, a hand-width below the hip. SubQ pinch at 45°.
Diagram is a general illustration, not a medical instruction. Rotate sites every injection, keep 1 in (2.5 cm) between recent sites, and avoid scars, moles, bruises and the navel area.
Cycling
Research protocols only — not for routine use.
Timing & Interactions
When to take
Once daily short cycles (10–30 days). Timing of day is not critical.
Do not combine with
- ·Active malignancy
- ·Concurrent anabolic hormone therapy without oversight
Complements
- ·GH secretagogue stacks for lean mass cycles
Storage & Reconstitution
Powder (Pre-Reconstitution)
Lyophilized powder: refrigerate 2–8°C for up to 24 months, or freeze at –20°C for extended storage. Keep sealed, desiccated, and protected from light.
After Reconstitution
After reconstitution with bacteriostatic water, refrigerate at 2–8°C and use within 28 days. Discard if cloudy, discolored, or precipitated.
Notes
Do not freeze after reconstitution — freeze/thaw cycles degrade most peptides.
Reconstitution Calculator
Concentration
2.50 mg/mL
Volume per dose
0.100 mL
Insulin syringe
10.0 units (U-100)
1 mL = 100 units on a standard U-100 insulin syringe. Draw to the nearest 0.5 unit and confirm dosing with a clinician before injection.
Your Notes
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Benefits
- ·Muscle hypertrophy in models
- ·Anti-fibrotic
- ·Potential for sarcopenia (theoretical)
Risks
- ·Oncogenicity concern (myostatin suppression)
- ·Gene-therapy safety unknowns
- ·No approved human dosing
Contraindications
- ·Active malignancy
- ·Pregnancy
- ·Pediatric
Regulatory
Not FDA-approved; research use only
Veterinary Use (Pets)
No established veterinary protocol for Follistatin 344. Consult a licensed veterinarian before considering off-label use in any species.
Full veterinary reference →Functional Groups
Cited Works
- Lee SJ. Quadrupling muscle mass in mice by targeting myostatin & follistatin. PLoS ONE. 2007;2:e789.source