Which according to you is better Amphetamine or Methyl Phenidate?
Which of these is better for improving concentration Amphetamine or Methyl Phenidate?
Do their different generic forms differ in their activity?
If you have taken these what is the difference you felt between them?
Do the just improve concentration and attentiveness or they also enhance some other things,say for example cognitive ability?
Do you really think it improves concentration?
Which has more side-effects?