Old female mice on semaglutide lived 12% longer and ran 2.8× as long before exhaustion. Other gains: > treadmill time to exhaustion +177% > hanging time +124% > rotating-rod performance +47% > open-field movement +50% > glucose tolerance: area under the curve −20% > Improved spatial memory: maze escape time −57% > reduced inflammation -55% > reduced senescence -65% > stem cell rejuvenation: hippocampal neurons ~3x > bone marrow colonies +44% > DNA damage & stress -44% Treatment started at 20 months of age (human equivalent to 60s). Control was a separate group of mice on a 24% food restriction to replicate semaglutide's weight and fat loss. Diet restriction reproduced the endurance and motor gains. It failed to match semaglutide on exploration, spatial memory, and blood sugar control. The weight loss explains the physical stamina however the semaglutide drove neurogenic, metabolic, and cellular pathways.