The present invention provides a method of digitizing nutritional status, muscle turnover, and risk assessment using the formulas containing four amino acids, which are Histidine, Leucine, Ornithine and Phenylalanine. The method of present invention can provide information regarding personalized nutritional status, muscle turnover and risk assessment, understand the effect of nutrition intervention, assist muscle growth and the effect of rehabilitation training, and improve patients' quality of life and bodily function.
