Essential amino acids, or EAAs, are amino acids that our body needs but cannot produce on its own, and there are 9 of them: Histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.

本，称 EAA，是我们身体需要但不能自己产的，其中有 9 种：组，异，，赖，蛋，苯丙，苏，色和缬。

I would say that we do not add leucine alone because leucine, isoleucine, and valine go hand in hand.

我认为我们不会单独添加，因为、异和缬是相伴而行的。