"Consume in small, frequent amounts. Between 20-200 mg/hour may be an optimal dose for cognitive function. Caffeine's effects can be maximized or minimized depending on what else is in your system at the time. Definitely add sugar. Grapefruit juice may prolong the effects of caffeine, while nicotine may speed up the body's metabolism of it." \\ I've been drinking **grapefruit juice** in the mornings with coffee for the last couple of months -- surprisingly, it does seem to work as noted! Comment on your experience. \\ Details from Chatham here: http://scienceblogs.com/develop... - Adriano

"Caffeine (0.3mg per kg of body weight [approx 20 mg per hour]) can support extended wakefulness, potentially by counteracting the homeostatic sleep pressure. Recall from memory may be improved by caffeine, possibly due to enhancements in memory encoding rather than retrieval per se. Theanine might actually potentiate the benefits of caffeine." -ibid. Grapefruit juice studies: http://www.ncbi.nlm.nih.gov/sites... and http://www.ncbi.nlm.nih.gov/pubmed... - Adriano