Background: Coffeeberry extract, rich in chlorogenic acids, shows promise in improving mood and cognition, particularly when co-supplemented with phenolic compounds. However, limited work has considered the effects of coffeeberry in isolation, especially at low doses. Objective: The current study investigated the effect of low and moderate doses of coffeeberry extract on cognition and mood. Design: This randomized, double-blind, placebo-controlled crossover design investigated three active beverages on a sample of 72 healthy adults aged 18–49 years. The investigational beverages contained 100 mg or 300 mg coffeeberry extract (standardized to 40% chlorogenic acid), or 75 mg caffeine (positive control). Cognition, mood, and subjective energy were measured at baseline and then again at 60 and 120 min post-treatment. Results: Analysis revealed no effect of 300 mg coffeeberry extract, while 100 mg resulted in increased mental fatigue during the performance of cognitively demanding tasks (p= 0.025) and decreased accuracy on a task of sustained attention (p= 0.003), compared to placebo, at 60 min post dose. Conclusions: Administration of 100 mg and 300 mg coffeeberry extracts revealed limited, transient negative effects following 100 mg coffeeberry. Given the large number of outcome measures analysed and the absence of findings following the 300 mg dose, these negative findings should be interpreted with caution. Overall, the findings of the current study suggest that coffeeberry extract at a low or moderate dose does not have a beneficial effect on mood, mental and physical energy levels, or cognition; higher doses, as have been administered previously, may be more effective.