Follistatin 344

Follistatin is an endogenous glycoprotein that binds and neutralises myostatin (GDF-8) — the transforming growth factor-β family protein that functions as the primary biological brake on skeletal muscle growth. Animals with myostatin deletion or Follistatin overexpression develop dramatically increased muscle mass (the 'double muscling' phenotype seen in Belgian Blue cattle and myostatin-null mice). Follistatin 344 is a specific isoform of the naturally occurring protein engineered for subcutaneous delivery. By neutralising myostatin's inhibitory signal, Follistatin 344 removes the genetic ceiling on muscle hypertrophy, allowing greater response to resistance training stimulus.

The pre-clinical data on myostatin inhibition is extraordinary — myostatin knockout mice develop approximately 200% more muscle mass than wild-type controls. A 2009 gene therapy study using Follistatin in rhesus macaques showed sustained muscle hypertrophy of 15% without detected adverse effects. One small human study (Jerry Mendell, Ohio State, 2015) used Follistatin gene therapy in Becker muscular dystrophy patients and demonstrated safety and modest functional improvement. However, this is gene therapy, not peptide administration — the extrapolation to subcutaneous Follistatin 344 peptide use is significant and the evidence base for that specific application in healthy individuals is essentially pre-clinical only. ProtocolHub considers this advanced research territory requiring specialist oversight.

10–30 day courses — not for continuous use