How protein excreted from the body?

Proteins are primarily broken down into their constituent amino acids during digestion, and excess amino acids are deaminated in the liver. The resulting ammonia is converted to urea, which is then transported to the kidneys. The kidneys filter urea and other waste products from the blood, excreting them in urine. A small amount of protein can also be lost through sweat, feces, and shedding of skin cells.