Improved cognitive performance in human volunteers following administration of guarana (Paullinia cupana) extract: comparison and interaction with Panax ginseng
Key Finding
Caffeine significantly improved attention, speed, and accuracy, with enhanced effects when combined with theanine.
Plain-English Summary
This randomized, double-blind, placebo-controlled study examined the acute cognitive effects of caffeine in various forms in 129 healthy young adults. The study compared caffeine alone, guarana extract (containing caffeine), and combinations with other nootropics.
Results showed that caffeine significantly improved attention, psychomotor speed, and accuracy on cognitive tasks. Effects were dose-dependent, with 75mg producing noticeable benefits. Interestingly, whole plant extracts containing caffeine produced different cognitive profiles than isolated caffeine, suggesting synergistic compounds in plants like guarana and tea.
The study found that caffeine's cognitive benefits were enhanced when combined with L-theanine, as found naturally in tea. This combination produced more balanced improvements in attention without the jitteriness sometimes associated with caffeine alone. Effects were observable within 30-60 minutes and lasted 3-4 hours. The study reinforces caffeine's well-established role as a cognitive enhancer.