Rhodiola rosea has some great research behind it. It is an adaptogen, and helps to increase your ability to deal with chemical, biological and physical stress. It influences our neurotransmitters and beta-endorphins in our brain. Helping to normalize neurotransmitters in the CNSnwithout causing drowsiness or altered mental status. It has been shown to increase mental performance, improve concentration, as well enhance mood and over all well-being. I have seen this work very well in people with ADHD in particular!