Nowadays, the importance of muscle mass, strength, and metabolic function is demonstrated in both the daily life activities and prognosis. However, the evaluation of muscle mass is not routinely measured by doctors. Clinically, the loss of muscular mass is classified as: muscular wasting, sarcopenia, cachexia. The pathogenesis of sarcopenia-wasting-cachexia is multi-factorial. Indeed, imbalance between anabolic and catabolic signaling, named as “hypermetabolic syndrome”, is the fundamental cause of muscular loss. The evaluation of muscular metabolic impairment should consider several aspects. Body mass index (BMI) is a good first step to use. However, BMI cannot distinguish lean muscular from fatty mass. Therefore, muscle and global catabolic/anabolic metabolism can be measured by: (a) anthropometric measurements, (b) dual-energy X-ray absorptiometry (DEXA or DXA), visceral proteins as blood albumin, transferrin, prealbumin, (c) total lymphocytes blood count, (d) nitrogen balance. Several therapeutic strategies have been proposed to cure muscle loss. Recent works showed that specific mixtures of aminoacids, including essential one, calculated according to stoichiometric ratio, counteract sarcopenia. Other intriguing approaches to muscular loss have been recently proposed. A recent trial showed that Amalirin can reverse muscle wasting in cancer cachexia. In addition, anabolic process can be also modulated by stimulation of selective androgen receptor modulators in humans and by activation of activine type II receptor of Myostatin in both animal models and humans. One other animal study shows that anabolic/catabolic transforming agent MT-102 reverses muscle wasting in rat. Muscular wasting, sarcopenia and cachexia are conditions with important clinical, social and economic impact. However, they are often underestimated by the patients and/or not properly evaluated and cured by physicians. Specific work must be planned and organized to sensitize the “person” on estimating and maintaining the muscle mass and its metabolic and functional roles since they are fundamental in both healthy people and ill patients.