Way back in the friggin 90s when I first started helping folks with the MCAT as a one-on-one tutor, occasionally a student would ask me what I thought about 'smart pills'. I would start in with some positive features and benefits. Then I would say, 'Funny you should mention, but I'm actually a rep for a few good companies.' Then I would start to open my briefcase to offer them samples. It was actually pretty humorous. Maybe you had to have been there.
I think it's good to keep in mind that the habits of life you establish in preparing for the MCAT will be the same ones you will have in medical school. It's not a sprint. It's a marathon. Relying on pills for learning will have your body breaking down in residency, even if it's 'just' megadoses of vitamins, theanine, and caffeine. Overuse of vitamin b12 can have serious side-effects. Caffeine too. Use rest, meditation, and clean living! A doctor's first patient is themselves.