In terms of staying power, the products with the highest percentage of staying power are those which use a lot of protein and other essential fatty acids. Protein helps to keep the liver and muscles working together as a whole, so it will work in your favor with testosterone production. Easier said than done, but there are things you can do. First and foremost, I suggest taking a supplement that has a high percentage of leucine and/or is a good source of other amino acids, such as whey, which is already available in some major supermarkets. Additionally, the amino acid branched chain amino acids (BCAAs) are essential to testosterone production, and are found in a number of foods such as eggs, fish, cheese, liver, liver, and green leafy vegetables. BSAAs are found in plant foods as well, but most of these products don't have much leucine. Also, BCAAs can be converted into testosterone naturally, and a product that is low in BCAAs will have a lesser effect on your testosterone. If you are taking an aromatase inhibitor or are using a hormone blocker, these products can block the conversion of the BCAAs into testosterone. If you want to get more leucine, I recommend looking at supplements that include leucine, l-cysteine, and creatine.