@donasmrs-- I take a 400mg Korean ginseng root supplement. It's great but I can't take it daily or in the evening because it gives me insomnia. I usually take it a few times a week, early in the morning so that the effects wear out by night-time.
My husband takes ginseng root too but he doesn't experience any of these problems. So if you're sensitive to stimulants, then try a small dose of ginseng root while starting out.