Anti-Follistatin antibodies are used for the immunodetection of the protein encoded by the FST gene. In humans, the canonical protein has a reported length of 344 amino acid residues and a mass of 38 kDa. It is known to be a secreted protein. Alternative splicing is reported to yield 2 different isoforms for this protein. It is known to bind directly to activin and functions as an activin antagonist. Post-translational modifications have been described, including glycosylation. Other names for this target antigen include FS and activin-binding protein. Gene orthologs have been identified in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species. A number of Follistatin antibodies have been mentioned in research publications and have associated citations. Western Blot is a widely used application for these antibodies. ELISA and Immunohistochemistry are also common applications.