Essential amino acids are non-synthesizable by the human body, meaning they must be obtained through the diet. They play critical roles in processes such as protein synthesis, tissue repair, and various metabolic functions. In contrast, non-essential amino acids can be synthesized by the body and do not need to be consumed through food. While both types of amino acids are vital for health, a balanced diet containing all essential amino acids, often found in complete protein sources, is crucial for optimal bodily function, particularly for athletes and individuals engaging in intense physical activity.