GLOSSARY

BCAA Catabolism breaks these amino acids down with important peripheral-tissue involvement.

Leucine, isoleucine and valine are branched-chain amino acids with important peripheral processing, including muscle. Carbon fates differ: leucine is ketogenic, valine glucogenic, and isoleucine contributes to both. This classification does not remove their essential building roles. Carbon routing does not prove universal benefit from isolated supplements or replace complete protein and adequate energy. A signaling or oxidation pathway should not be equated with the full requirement for muscle protein synthesis and recovery.

Amino acids support proteins and other compounds, while carbon skeletons can enter energy pathways after nitrogen handling. There is no unlimited dedicated amino-acid store comparable to fat storage. Oxidation of some protein does not prove total intake inadequate or unlimited extra intake builds more muscle. Athletes need total amount, quality, distribution and adequate energy alongside training load. Carbon fate, nitrogen disposal and protein synthesis are separate processes rather than one simple anabolic-versus-waste label.

Gluconeogenesis makes glucose from lactate, glycerol and some amino acids, with major hepatic and context-dependent renal contributions. It costs energy and is not a simple reversal of all glycolysis. Even-chain fatty-acid acetyl units do not normally provide direct net human glucose; glycerol and other routes require separate treatment. Endogenous production does not automatically eliminate exercise fueling needs, particularly at high demand, and precursor availability is only one part of pathway regulation.