Guarana (Paullinia cupana) as a tool for helping with Fatigue / low energy

This systematic review with meta-analysis assessed guarana (Paullinia cupana) for managing cancer-related fatigue across seven studies (427 patients). In the pooled breast-cancer analysis, guarana was not superior to placebo for reducing cancer-related fatigue, and the quality of evidence was very low, indicating the need for further well-designed studies.

In a double-blind crossover trial, eleven endurance-trained participants ingested caffeine, guarana (Paullinia cupana, containing 130 mg caffeine) or placebo before cycling. Guarana improved 15-min time-trial work output versus placebo, with lower perceived exertion, indicating an ergogenic effect possibly involving central mechanisms reducing perceived effort.

The present study aimed to systematically assess acute, dose-related behavioural effects of an extract of guaraná plant for the first time in humans. This double-blind, counterbalanced, placebo-controlled study (n=26) assessed the acute mood and cognitive effects throughout the day of four different doses (37.5 mg, 75 mg, 150 mg and 300 mg) of a standardised guaraná extract (PC-102). Assessment included the Cognitive Drug Research computerized test battery and Bond-Lader mood scales. Guaraná improved secondary memory performance and increased alert and content mood ratings. The two lower doses produced more positive cognitive effects than the higher doses. This research supports previous findings of cognitive improvements following 75 mg guaraná and provides the first exploration of different dose effects of guaraná in humans. The findings suggest that the effects cannot be attributed to caffeine alone.

In high-fat-diet-fed mice, guarana (Paullinia cupana) reduced body weight, adipose depots, glycaemia and triglycerides, increased oxygen consumption and energy expenditure, and stimulated mitochondrial biogenesis in muscle and brown adipose tissue, demonstrating that guarana increases energy metabolism and helps control weight gain.