Positives

• Patients with sporadic inclusion-body myositis treated with AAV-delivered follistatin gene therapy showed measurable gains on the 6-minute walk test and slowed disease progression compared with natural-history controls PMC.
  
  
• Becker muscular dystrophy participants in the same gene therapy trial regained ambulation distance after years of decline PMC.
  
  

Negatives

• Some peptide users reported fatigue, headaches, and flu-like symptoms during high-dose follistatin-344 cycles PMC.
  
  
• Because follistatin also binds activin and other TGF-beta ligands, patients risk off-target endocrine effects that have not been mapped in human dose-response studies PMC.
  
  

Hurdles & Side Effects

• Subcutaneous follistatin-344 has no published human dose-response data, so patients with post-viral muscle wasting are essentially self-experimenting outside any clinical framework Nature Scientific Reports.
  
  
• The robust clinical evidence comes from sustained gene-therapy expression, a fundamentally different exposure pattern than the brief peaks produced by injected peptide PMC.