even if you are shit-hot and in perfect shape and acclimitisation you are gonna suffer after a big climb.
say, for instance, Bachar and Croft after the first link up of El Cap and Half Dome in a day. ya think they went out the day after and cranked off a couple 5.12 free solos, or did they spend the day in the deli siloing cinnamon buns? do you think any magic powder or drink would have had them out soloing 12s? no? hmmmm