How One Amino Acid Touches Two Aging Pathways

L-arginine is usually treated as a simple nitric-oxide precursor, a molecule with a narrow vascular role. But across multiple lines of research, it keeps appearing in places it shouldn’t: improving cerebral blood flow in older adults, shifting cognitive performance, and, most unexpectedly, altering how amyloid-β proteins aggregate in the brain. This episode unpacks why these effects are so unusual, and how they connect to the long-standing arginine paradox: the biochemical mismatch between ho...