Registered Dietitian Says This Amino Acid Is the “On Switch” for Muscle Growth

Most people know the basics of building muscle: lift heavy and eat your bodyweight in protein. But once you move past the beginner stage, those gains don’t come as easily. At the intermediate and advanced levels, fine-tuning both your diet and your training becomes essential if you want to keep adding size. Some nutritionists even swear by a single amino acid, leucine, as a key tool for dialing in muscle growth.

Found in high amounts in whey protein, leucine has long been recognized as more than just a building block.