This is the best I have tried. Since taking this product I have greatly increased the weight and reps in the gym. Unlike similar supplements offered by other companies, I have no jitters, sleep disruption, or any other side effects. My sleep is much better, and my muscle recovery is a whole lot better. Like most supplements, it takes a week or so to build up in your system, but for the price and a 3 month supply, you cannot beat this. 2 pills a day versus other products that have the dosage at 4-8 pills spread throughout the day. Sorry too busy for that. I will definitely be ordering again.