The exact mechanism of Modalert nootropic drug is not known yet. Studies are still going on this medicine. Modalert falls into the category of drugs called eugeroics, which works to enhance the stimulation in your brain. This drug efficiently works for inhibiting certain brain chemicals that cause sleepiness. Modafinil present in Modalert acts on your brain and helps to improve cognitive functions that help you to enhance brain alertness and brain function. Besides, its onset action time is still unclear.