If you’re looking to add mass, muscle growth requires a delicate balance of muscle buildup and muscle breakdown. Muscle buildup is technically known as muscle protein synthesis. This involves the assembling of amino acids into the proteins that make up muscle fibers. Muscle breakdown involves the removal of amino acids from these proteins. Most bodybuilders make the mistake of focusing only on muscle buildup (synthesis) by using supplements that primarily boost protein synthesis. Yet impeding muscle breakdown, technically known as catabolism, is just as important as increasing muscle protein synthesis.

That’s because muscle growth occurs only when muscle protein buildup increases at a greater rate than muscle protein breakdown. To mix our metaphors a bit, a good analogy is a brick wall, where the bricks symbolize amino acids. If you add three bricks to the wall (protein synthesis) but five bricks fall off (catabolism), the wall gets smaller. If you add five bricks and only three bricks fall off, the wall gets bigger.

Supplements that increase protein synthesis act like a mason adding bricks to a wall—they help to add more bricks (amino acids) to your muscles and build them up. Supplements that prevent muscle breakdown act like mortar that’s added to the wall to keep bricks from falling off. So by preventing amino acids from being taken away from your muscles, these supplements help your muscles grow by allowing synthesis (buildup) to prevail and muscle growth to occur. To maximize your muscle growth, you need to know which supplements increase protein synthesis, which ones decrease muscle breakdown and which ones do both. Here is your definitive guide to maintaining this delicate balance so you stay in positive muscle-growth mode.