A proprietary blend is a group of ingredients listed on a supplement label under a single name with only the total combined weight disclosed — not the individual dose of each ingredient. You know what's in the product, but you have no idea how much of each ingredient you're actually getting. It's legal, it's widespread, and it's the single biggest obstacle to making an informed supplement purchase. Do Vitamins has never used a proprietary blend and never will — every ingredient and every dose in PurePump is fully disclosed on the label.

BCAAs (branched-chain amino acids) are three essential amino acids — leucine, isoleucine, and valine — that your body can't produce on its own. They play a direct role in muscle protein synthesis, reducing muscle breakdown during exercise, and delaying central fatigue. Leucine is the standout, acting as the primary trigger for muscle building through the mTOR pathway. The honest truth? If you eat adequate protein, you're likely getting enough BCAAs from food. But as part of a pre workout formula, they provide targeted muscle-protective support during training when it matters most.