Effects of a commercial product containing guaraná on psychological well-being, anxiety and mood: a single-blind, placebo-controlled study in healthy subjects.

Background: Guaranà (Paulinia cupana) seed extracts are increasingly popular worldwide for their stimulant, cognitive and behavioral effects. To assess the effects on psychological well-being, anxiety and mood of a commercially available guaranà preparation taken regularly over several days according to the labelled dosages and instructions, 27 healthy volunteers were enrolled in a prospective, randomized, single-blind, placebo-controlled, crossover study.

Results: Guaranà 350 mg × 3 daily just after breakfast or placebo were given for 5 consecutive days. Assessment was performed one day after the last intake and included the psychological well-being (PWB) scales, the self-rating anxiety state scale (SAS), and the Bond-Lader mood scales. There were no significant differences between guaranà and placebo in any of the 6 areas of PWB, in SAS, as well as in any of the 16 mood scales.

Conclusions: In healthy subjects a 5-day treatment with a commercial preparation of guaranà used according to labelled instructions provided no evidence for any major effects on psychological well-being, anxiety and mood. Considering the increasing popularity of guaranà-containing products sold as dietary supplements for fitness purposes, controlled studies are strongly warranted to assess their benefits in comparison to the labelled claims.