L-phenylalanine is an essential amino acid, which is the basic building block of proteins. It cannot be synthesized by itself in the body and must be consumed through diet. L-phenylalanine can be converted into other important compounds in the body, such as tyrosine, norepinephrine, and dopamine. L-phenylalanine is an important essential amino acid that has multiple health benefits and is widely used in nutritional supplements, emotional and mental health, sports nutrition, and weight management.