There are nine essential amino acids that must be obtained from the diet, as the body cannot synthesize them independently. These amino acids—histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine—are critical for various bodily functions, including protein synthesis, hormone production, and enzyme function. Consuming a balanced diet rich in quality protein sources ensures adequate intake of these essential amino acids, supporting overall health and muscle growth.