Coffee stimulates the production of serotonin, dopamine, and noradrenaline, which help regulate mood and cognitive function in the brain. The most effective time to have a cup of coffee is between 9:30 am and 11:30 am, when the level of cortisol in our body is not high. Many controlled trials in humans show that coffee improves various aspects of brain function. This includes memory, mood, vigilance, energy levels, reaction times and general cognitive function
Darruda 