Cancer patients display systemic inflammation, which leads to an increase in protein catabolism, thus
promoting the release of free amino acids to further support metabolism and remodelling of muscle proteins.
Inflammation associated with tumor growth leads to malnutrition, a factor that increases the risk of developing
cachexia. With cancer-induced cachexia, nutritional interventions have gained traction as a preventative method
to manage this condition. Currently, cancer consensus recommendations suggest a protein intake above 1.0
g/kg.day-1 up to 2.0 g/k.day-1 for cancer patients, although an ideal amount for some amino acids in isolation has
yet to be determined. Due to controversy in the literature regarding the benefits of the biochemical mechanisms of
various muscle mass supplements, such as L-leucine (including whey protein and BCAA), β-hydroxy-beta-methyl
butyrate (HMβ), arginine, glutamine and creatine, several studies have carefully examined their effects. L-leucine
and its derivatives appear to regulate protein synthesis by direct or indirect activation of the mTORC1 pool of
kinases, further promoting muscle protein balance. Arginine and glutamine may act by reducing inflammation
and infection progression, thus promoting improvements in food intake. Creatine exerts anabolic activity, acting
as an immediate energy substrate to support muscle contraction further increasing lean mass, mainly due to
greater water uptake by the muscle. In this narrative review, we highlighted the main findings regarding protein
consumption and amino acids to mitigate cancer-induced skeletal muscle depletion.