Which amino acids can be synthesized from other amino acids?

Non-essential amino acids are the amino acids that can be synthesized by the body from other amino acids. Unlike essential amino acids, which must be obtained through diet because the body cannot produce them, non-essential amino acids are created through various biochemical pathways. For instance, the body can convert certain precursor molecules from the diet or from the metabolism of existing amino acids into different non-essential amino acids as needed for protein synthesis and other cellular functions.

In contrast, essential amino acids cannot be synthesized by the body and must be obtained from food sources, leading to their designation as "essential." The complete amino acids terminology generally refers to proteins that contain all essential amino acids, while conditional amino acids are typically those that are non-essential but may become essential under certain physiological conditions, such as illness or stress. Thus, the classification of amino acids into non-essential is key to understanding their synthesis and the body's ability to produce them from other sources.