Follistatin 344 vs MK-677 (Ibutamoren)
Side-by-side comparison of key properties, dosing, and research.
Anabolic & IGF
Follistatin 344Growth Hormone Peptides
MK-677 (Ibutamoren)- Summary
- Follistatin 344 is a recombinant form of the endogenous follistatin protein. It inhibits myostatin and activin — the primary negative regulators of muscle growth — potentially removing the genetic ceiling on muscle development. It is one of the most theoretically powerful anabolic compounds but is experimental with limited human data.
- MK-677 (Ibutamoren) is an orally active, non-peptide ghrelin receptor agonist that increases growth hormone and IGF-1 levels. Unlike injectable GHRPs, it can be taken orally and has a 24-hour half-life, making it convenient for sustained GH optimization.
- Half-Life
- ~24–36 hours
- 24 hours
- Admin Route
- SubQ, IM
- Oral
- Research
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- Typical Dose
- 100 mcg
- 10–25 mg
- Frequency
- Once daily
- Once daily
- Key Benefits
- Inhibits myostatin — removes muscle growth ceiling
- Significant increases in muscle mass and strength
- Reduces fat mass
- Promotes bone density
- May stimulate hair follicle cycling
- Anti-fibrotic effects in muscle tissue
- Synergistic with IGF-1 and other anabolic peptides
- Increases lean muscle mass
- Enhances bone density
- Improves sleep quality and REM sleep
- Accelerates recovery from training
- Increases appetite
- May improve skin elasticity and appearance
- Supports fat loss while maintaining muscle
- Oral administration — no injections required
- 24-hour half-life allows once-daily dosing
- Side Effects
- Muscle soreness (from rapid hypertrophy)
- Potential reproductive effects (activin inhibition)
- Unknown long-term safety profile
- Possible esophageal effects at high doses (animal data)
- Increased appetite (significant in some users)
- Water retention and puffiness
- Elevated blood glucose / insulin resistance (monitor in diabetics)
- Lethargy initially
- +2 more
- Stacks With
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