Amino acids are the building blocks of protein. Proteins are long chains of amino acids. Your body has thousands of different proteins that each have important jobs. Each protein has its own sequence of amino acids. The sequence makes the protein take different shapes and have different functions in your body.

You can think of amino acids like the letters of the alphabet. When you combine letters in various ways, you make different words. The same goes for amino acids — when you combine them in various ways, you make different proteins.

Your body needs 20 different kinds of amino acids to function correctly. These 20 amino acids combine in different ways to make proteins in your body.

Your body makes hundreds of amino acids, but it can’t make 9 of the amino acids you need. These are called essential amino acids. You must get them from the food you eat. The 9 essential amino acids are: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine.

Your body produces the rest of the 11 amino acids you need. These are called nonessential amino acids: alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine.