The 14 Best Nootropics and Smart Drugs Reviewed Caffeine. Caffeine is the most widely consumed psychoactive substance in the world ( 1 ). ... L-Theanine. ... Creatine. ... Bacopa Monnieri. ... Rhodiola Rosea. ... Panax Ginseng. ... Ginkgo Biloba. ... Nicotine. More items... Jan 26, 2022