Phenylketonuria (PKU) is a genetic metabolic disease resulting from a deficiency in the enzyme phenylalanine hydroxylase. This defect prevents the conversion of phenylalanine to tyrosine, and as a result, the level of phenylalanine in the body increases abnormally. The accumulation of this amino acid may cause brain damage and grows development in these patients. The primary approach to treating the disease involves dietary management that restricts protein and phenylalanine intake, often alongside Tetrahydrobiopterin (BH4) supplementation. Medical foods specifically formulated for these patients are utilized to supply the necessary energy, protein, and tyrosine. Other treatment options, including the use of large neutral amino acids (LNAAs) and the enzyme Phenylalanine ammonia lyase (PAL), can be utilized to manage symptoms in adult patients. Advancements in gene therapy aimed at correcting defective genes in patients may help restore phenylalanine metabolism, though further research in this area is necessary. Effective personal management of phenylketonuria necessitates enhanced knowledge and collaboration among healthcare professionals to achieve optimal treatment outcomes for patients. This article emphasis the nutritional management of individuals with phenylketonuria across various stages of their lives.