Caffeine might increase energy levels, and do other things, but it is ridiculously inaccurate to say “caffeine makes you less sleepy” as its main effect. Try modafinil/caffeine double blind test—modafinil is not “stronger caffeine”, it’s completely different, by actually reducing sleepiness without any energy boost. Amphetamines are even more complicates.
Caffeine might increase energy levels, and do other things, but it is ridiculously inaccurate to say “caffeine makes you less sleepy” as its main effect. Try modafinil/caffeine double blind test—modafinil is not “stronger caffeine”, it’s completely different, by actually reducing sleepiness without any energy boost. Amphetamines are even more complicates.