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Bioalmanac

Follistatin-344

FS-344 · Follistatin 344

Preclinical

Status reviewed 16 Aug 2026

Prohibited in sport

A myostatin-blocking protein with dramatic animal results, no human trials, and a serious question over whether what is sold is the real thing.

Storage

Freeze-dried powder
Refrigerated at 2–8 °C, protected from light.
After mixing
Refrigerated at 2–8 °C, and used quickly. A large glycoprotein is far less stable in solution than a short peptide, and it will not look any different once it has lost activity.
Long-term, frozen
Unopened powder at −20 °C or colder. Avoid freeze-thaw cycles entirely. Each one degrades a protein of this size.

Reconstitution — 1 mg vial, 200 mcg dose

On a 1 mL U-100 syringe. Check every figure against your own vial before drawing.

Water addedConcentrationVolume to drawUnitsDoses per vial
1 mL1 mg/mL0.2 mL20 units5
2 mL0.5 mg/mL0.4 mL40 units5
3 mL0.333 mg/mL0.6 mL60 units5
5 mL0.2 mg/mL1 mL100 units5

Dose ranges reported in sources

Descriptions of what sources report, not recommendations.

GoalRangeFrequencySource
Commonly described community protocol100–300 mcgDaily for a course of 10 to 30 daysCommunity practice

When to stop

  • Nosebleeds, or new visible small blood vessels in the skin. These are the specific effects that halted the ACE-031 trials.
  • Unusual bruising or bleeding that does not stop normally.
  • Any allergic response: rash, hives, facial swelling or difficulty breathing. Seek urgent care.
  • Changes in libido, menstrual cycle or testicular size, which would suggest reproductive axis effects.
  • Any new lump or unexplained persistent pain.

Not approved anywhere, and never studied in a human trial as an injectable protein. Follistatin gene therapy has been studied in small trials for muscular dystrophy. The most advanced pharmaceutical work on the myostatin pathway — using a different molecule — was halted for safety.

Arithmetic on values you enter. Not medical advice. Not reviewed by a clinician. · bioalmanac.com/peptides/follistatin-344

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