Liver diseases and in particular end stage liver diseases are frequently complicated by muscle modifications that are linked to worse clinical outcome. In addition, recent studies have demonstrated the negative impact of these muscle changes on liver function leading to the hypothesis of a bidirectional relationship referred in the literature as “muscle-liver axis”. In a context of evolution towards a more holistic and less organocentric vision of medicine, studying frailty, myosteatosis and sarcopenia and their underlying pathophysiological mechanisms has led to many publications in the last five years. These studies are describing several pathophysiological mechanisms, highlighting the extremely complex character of this relationship. This review aims to summarize these mechanisms as well as potential therapeutic targets, independently of liver disease etiology.