Some of the most serious consequences of ageing are its effects on skeletal muscle particularly the progressive loss of mass and function which impacts on quality of life and longevity. Sarcopenia is characterised by a deterioration of muscle quantity and quality leading to a slowing of movement and a decline in strength. Understanding the biological mechanisms underlying sarcopenia is critical for developing safe and effective interventions. The pathophysiology of sarcopenia involves a complex interaction of factors affecting neuromuscular transmission, muscle architecture, fibre composition, and excitation-contraction coupling, leading to impairments in contractility and metabolism. Many factors influence the rate and magnitude of muscle atrophy and weakness with advancing age, including nutrition, hormones, genetics, motor units, inflammation, oxidative stress and physical activity. These can work synergistically to counteract and slow sarcopenia, or exacerbate and hasten muscle decline. Sarcopenia has been linked with a chronic disturbance in the regulation of muscle protein turnover leading to an imbalance between synthesis and breakdown. Exercise alone cannot prevent sarcopenia but combining it with good nutrition (especially adequate protein), can attenuate progression and promote functional independence and quality of life. There is growing appreciation for a systems physiological understanding of sarcopenia; considering age-related alterations in signalling between organ systems and tissues, not just muscle. Skeletal muscles secrete myokines, metabolites, microRNAs, and exosomes, many of which are regulated by exercise. Interpreting this signalling interplay will help identify novel targets and treatments. Pharmacological therapies specifically for sarcopenia have not been widely pursued, but some have been evaluated in phase 2 (or higher) clinical trials. Promising candidates include growth promotants like myostatin inhibitors, testosterone (and derivatives), β-agonists, and SARMs. Such drugs can have deleterious off-target effects and separating beneficial from harmful effects must be achieved for clinical application. Combining pharmacotherapies with exercise is possible but requires further evaluation to determine efficacy and safety.