Not sure if this is the thread for talking about caffeine, it’s been discussed quite a bit on the forum elsewhere, but…
From what I’ve read, caffeine helps performance if used intermittently, but not if used all the time. I know one of Canada’s top sp[rinters in 96’ used to take 400mg or caffeine before a race (with L-Tyrosine and I think something else…all perfectly legal). I would let my athletes use caffeine before competitions, but with a few of them it made them too nervous and as a result they lost their appetite and wouldn’t eat before their races, and they would run tight, not relaxed.