Muscle protein synthesis (MPS)

Muscle protein synthesis is the metabolic process by which amino acids are incorporated into new proteins within skeletal muscle tissue. This ongoing turnover allows muscles to grow after resistance training, repair damage from exercise or injury, adapt structurally over time with training stimuli, and maintain overall function throughout life. The rate of this process determines whether net muscle mass increases or decreases depending on its balance with concurrent breakdown processes. Essential amino acids—especially leucine—are critical regulators via activation of the mTOR pathway that governs translation initiation for new protein assembly. While vital for health across all ages, rates decline significantly after age twenty and are influenced by diet quality/protein intake as well as physical activity patterns.[1][6][7]

Other names

MPSSkeletal muscle protein synthesisProtein anabolism in muscle

Not applicable for the process itself; for drugs/nutrients that modulate it: - Activation of mTOR signaling pathway by leucine/BCAAs enhances translation initiation and ribosome biogenesis leading to increased MPS[6]. - Hormonal modulation via anabolic steroids increases transcription/translation machinery activity.