The present invention is the field of anti-activin receptor IIB (ActRIIB) antibody. Specifically, it is related to antibody what treatment disorder of muscle, as because of amyotrophic purposes caused by disease or useless use.本發明是抗激活素受體IIB(ActRIIB)抗體的領域。具體而言,其涉及所述抗體用於治療肌肉病症,如因疾病或廢用引起的肌肉萎縮的用途。