The Muscle Brake

The human body produces a protein called Myostatin (GDF-8) which limits muscle growth to prevent muscles from becoming too large for the heart to support. Inhibiting this protein removes the “ceiling” on muscle hypertrophy.

Two Approaches to Inhibition

  • Follistatin 344: A naturally occurring protein that binds to and neutralizes myostatin. Research shows it can significantly increase muscle mass and reduce inflammation.
  • ACE-031: A soluble form of the Activin Receptor Type IIB. It acts as a “decoy,” trapping myostatin circulating in the blood before it can bind to muscle cells. It is generally considered more potent than Follistatin but was halted in human trials due to minor bleeding issues (nosebleeds), limiting it to research use.

Scientific References

  • Rodino-Klapac LR, et al. “Inhibition of myostatin with emphasis on follistatin as a therapy for muscle disease.” Muscle & Nerve. 2009.
  • Attie KM, et al. “A single ascending-dose study of muscle regulator ACE-031 in healthy volunteers.” Muscle & Nerve. 2013.