I have been taking the Advanced Amino Tabs for a month now, and I can definitely notice a difference in my energy level, and clearer thinking. I am over 70yrs, and am still working as a Bus Driver..... sometimes doing some long days, and also packing to move to another house, so the stress level is high and the pressure is on. It has taken a couple of weeks for me to notice a change, but it is quite obvious now, and I have not changed my diet , so it must be the Amino's. I plan on continuing taking these as long as I can get them into New Zealand as they certainly make me feel better.