Amino acids are biologically organic compounds that are merged together to form proteins. Together, these combinations are the building blocks of life. There are about 20 amino acids, eight of which are considered essential and the others non-essential or conditional.
When protein is digested, it is broken down into specific amino acids that are selectively put together for different uses. They help the human body grow, repair tissues, metabolize and also act as a source of energy. These new proteins that are formed also make up the solid matter of the body, like the eyes, skins, heart, intestines and muscles.
Essential amino acids, such as valine and lysine, come directly from food and cannot be made by the body. The non-essential and conditional amino acids are produced in the body for use in times of illness or stress. These include alanine and serine and are sometimes added to food supplements.