INS and sarcopenia: So, if melatonin exerts an inhibitory effect on insulin secretion [20,21], and many studies suggest that amino acids and insulin play major roles in promoting postprandial protein anabolism [22,23], the hypothesis arises that melatonin intake could have a detrimental effect on protein metabolism through the inhibition of insulin secretion, particularly in the case of sarcopenia, which has repeatedly been shown to be associated with resistance of muscle tissue to the anabolic effects of insulin [24].