Below, are the 20 biologically active amino acids in humans. In nature, there are more than 100 amino acids to be found. However, the human uses only 20 of them. Since amino acids are the buildint blocks of proteins, 20 different types of amino acids is quite alot for the body to work with in many respects. Imagine having an endless supply of 20 different colored bricks to build houses with? You can put them in different order each time, essentially creating an endless supply of designs. Proteins are no different. Think of proteins as the houses and amino acids as the bricks. Protein design can be virtually endless, and it is. There are thousands of types of proteins in nature, each with varying amounts of amino acids. The varying amounts of amino acids causes the proteins to conform to unique shapes and function.

Amino acids can be placed in the category of either essential or non-essential. The name is self explanatory. Essential amino acids are those that are "essential" in the diet. In other words, we cannot create them through our own metabolism. Therefore, we need to obtain them through foods containing them. Fortunately, protein-containing foods contain varying degrees of the essential amino acids. During times of starvation, our body relies on its own protein stores, such as pre-albumin, albumin, and ultimately protein from sources that it normally shouldn't have to utilize (e.g., muscle tissue, etc.)

Non-essential amino acids are those which can be produced from other amino acids and substances in the diet and metabolism. During times of need, the metabolism can shift into producing the amino acids that it requires for synthesizing proteins essential to our survival.

Below is a list of essential and non-essential amino acids. Click on the inidivual amino acids to learn more.