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Skeletal muscle (SM) is not only a locomotor unit responsible for the propulsion and regulation of energy and metabolic processes. Now it is also recognized as an organ capable of producing molecules with vital functions: the so-called myokines1. Over the past two decades, it has become apparent that the ME functions as an endocrine organ in response to exercise, which can produce and secrete hundreds of these myokines that exert their effects in an autocrine, paracrine, or endocrine manner, allowing for cross-talk. between the EM and other organs, including the brain, adipose tissue, bone, liver, intestine, pancreas, vascular bed, and skin, as well as with the EM itself. Although only a few myokines have been assigned a specific role in humans, the biological roles of myokines have been identified to include effects on cognition, lipid and carbohydrate metabolism, browning of white fat, bone formation, endothelial cell function, skin structure, and tumor growth. Some relevant myokines are interleukin-6 (IL-6), IL-8, IL-15, irisin, myostatin, fibroblast growth factor 21 (FGF21), and leukemia inhibitory factor (LIF), brain-derived neurotrophic factor (BDNF) and insulin-like growth factor-1 (IGF-1).