There are 20 primary amino acids necessary for humans, nine of which are essential amino acids. They’re essential because we need to get them from food, as our bodies cannot make them.

The reason: When you take essential amino acid supplements (also called "free-form amino acids “) they do not require digestion and will rapidly move from the stomach to the blood, he says.

Amino acids, which are a key ingredient of life, could have originally been made in interstellar molecular clouds like that from which the solar system formed, before winding up in asteroids that ...