Specialized products "Nutrigen" are produced from a mixture of crystalline L-amino acids without phenylalanine and constitute a "series" of products that it is advisable to consistently use in the clinical nutrition of patients with phenylketonuria as they mature. Considering the main age periods of life, products were created for 4 age groups of patients with PKU: infancy (from birth to 1 year), early childhood (from 1 year to 3 years), pre-school age (from 3 years to 7 years), school, adolescence (from 7 years and older), while all products intended for children of early, preschool and school age, if necessary, can be used in diet therapy for children over 1 year of age. The results of studies on the assessment of the tolerability and clinical efficacy of new domestic products based on amino acids without phenylalanine showed that these specialized mixtures of the Nutrigen and Nutrigen Premium series have satisfactory organoleptic properties, and are well tolerated by patients with PKU and have a positive therapeutic effect. Nutrigen 30, 70, 75 – for dietary management of PKU Nurigen 14- for patients with methylmalonic and propionic academia