An evaluation of the cognitive and mood effects of an energy shot over a 6 h period in volunteers. A randomized, double-blind, placebo controlled, cross-over study

•An energy shot without glucose was tested in mildly sleep deprived volunteers.•Attention, working and episodic memory, mood and alertness were assessed over 6 h.•Compared to placebo the shot improved alertness and all 6 domains of cognition.•The benefits lasted 6 h on 4 domains of cognition including episodic memory.•The caffeine content cannot explain the wide ranging and long lasting effects.

Energy drinks are widely available mostly containing glucose, and several have been demonstrated to improve alertness and cognitive function; these effects generally being identified 30–60 min after administration. The present study assessed whether an energy shot without carbohydrates would affect major aspects of cognitive function and also mood in volunteers over a 6 h time period. This randomized, double-blind, placebo-controlled, crossover study compared the acute effects of the energy shot with a matching placebo in 94 healthy volunteers. Cognitive function was assessed with a widely used set of automated tests of attention and memory. Mood was assessed with the Bond-Lader, Beck Anxiety Index, Beck Depression Index, Chalder Fatigue Scales (CFS), and the POMS. The volunteers were requested to limit their sleep to between 3 and 6 h the night before each testing day. Compared to the placebo, the energy shot significantly improved 6 validated composite cognitive function measures from the CDR System as well as self-rated alertness; the benefits on 4 of the cognitive measures still remaining at 6 h. The overall effect sizes of the performance improvements were in the small to medium range and thus notable in this field. In conclusion, an energy shot can significantly improve important aspects of cognitive function for up to 6 h compared to placebo in partially sleep-deprived healthy volunteers.