L-theanine elevates levels of GABA, as well as serotonin and dopamine. These chemicals are known as neurotransmitters and they work in the brain to regulate emotions, mood, concentration, alertness, and sleep, as well as appetite, energy, and other cognitive skills.

B vitamins play a key role in ensuring that the brain achieves its full potential. It helps maintain healthy nerve cells and red blood cells. Enough supply of vitamin B in your body can improve memory and help to sharpen your cells.

Caffeine appears to enhance concentration and improve motor control and alertness by creating changes in the brain. Caffeine also increases activity in parts of the brain consistent with the improved ability to focus.