Circulating levels of irisin in patients with anorexia nervosa and different stages of obesity - Correlation with body mass index

► Irisin is cleaved from fibronectin type III domain containing 5 (FNDC5). ► Plasma irisin levels are higher in obese compared to anorexia nervosa. ► Irisin correlates with body mass index, fat mass and fat free mass. ► Circulating irisin correlates with insulin but not ghrelin. ► Physiological function of irisin may be improvement of glucose tolerance.