Skip the black-five-sugars coffee and pop some NADH, a coenzyme that may increase mental alertness and concentration. In one New York-Presbyterian Hospital study, researchers tested 25 sleep-deprived people after the group had taken 20 milligrams of NADH and then again after they’d taken a placebo.

“When the people took NADH, they performed significantly better overall on a set of mental tests using a measure of speed and accuracy,” says Margaret Moline, Ph.D., one of the study researchers.

Look for supplements that say “ENADA” on the label; they contain the same NADH formulation used in studies.