Urea is a major organic component found in human urine, which is a waste product expelled by animals after being excreted from the kidneys. Urea, also known as carbamide, is a waste product after the production of proteins from the breakdown of amino acids.
The amino acids contain ammonia, which is toxic to human cells, so the liver converts it into urea, which is non-toxic. Water-based animals, including fish, expel the urea directly into the water; however, all land animals excrete it through urine. Urine is made up of soluble waste products from the human body as well as water and sugars.