I have been using whey protein powder and as such getting all my amino acids. I decided to add some BCAA capsules to see if they might augment my working out and muscle building. Boy, did they. I was really surprised. BCAAs are said to possibly provide additional energy but that is not their main emphasis. To my surprise, they gave me additional energy in the gym and nothing else changed with my supplement intake except adding in these BCAAs. I will watch to see how muscle growth takes place, too. Each time I make a protein drink I pull a BCAA capsule apart and put the BCAAs powder directly into my protein drink. I was skeptical that taking these BCAAs would do anything, but as I've mentioned, they did for me and I'm very surprised. I will continue to add these BCAAs into my protein drink. I highly recommend this supplement. And Optimum Nutrition is a great brand to trust. I've used their products for years and never been disappointed in any of their supplements.