FNDC5 and Insulin resistance: Evidence suggests that GLP-1RAs boost irisin release and reduce IL6 secretion after 6 months of treatment, indicating favorable effects on skeletal muscle and adipose tissue, as both irisin deficiency and chronic exposure to moderate-high levels of IL6 are associated with insulin resistance, impaired insulin secretion, poor glucose control, weight gain, expansion of visceral adipose tissue, and muscle hypotrophy [189,190].