I take L-tyrosine, A-GPC, ALCAR, and caffine before any type of studying. I love L-tyrosine because it just puts me in a great mood. Also works synergistically with caffine. I drop 2g tyrosine with 100-200mg caffine. Throw in ALCAR and A-GPC (if you got some lying around) and your just about ready for anything. Hoo-rah for tyrosine.