how many amino acids are there

There are roughly 500 amino acids identified in nature. However, only 20 amino acids make up the proteins found in the human body. Among these 20 amino acids, 9 are essential amino acids, which the human body cannot synthesize and must obtain from the diet, while the other 11 are non-essential amino acids that the body can produce on its own. Additionally, there are two more amino acids, selenocysteine and pyrrolysine, recently described but not commonly part of the standard 20 amino acids in humans.