I have been using Colloidal Copper (from here [link to shopcolloidalworld.com] ) for about 6 months now. Seem to give an energy boost and a sense of well being. When I stopped for a month because it was out of stock, I noticed my energy level going back down so it must be making a difference, but it's not like a caffeine kind of effect at all if you know what I mean. It's very gradual, yet very sustaining.