I have to confess I fell into the creatine thing for the past 5mo and it actually has made a difference in muscle mass. The longevity culture though mostly has little to do with solid science. Don’t get me started on methylation aging clocks I worked on age dependent methylation for awhile and mouse models of skeletal muscle aging. Recent papers show that 50+ % of longevity is heritable and that’s not using genome wide analysis. So it’s likely exercise does help but this is all heathspan, not longevity.