Which type of amino acid becomes essential under certain conditions?

Conditionally essential amino acids become essential under specific physiological conditions or stress situations. Normally, the body can synthesize these amino acids in sufficient quantities, meaning they are not required in the diet under typical circumstances. However, during times of illness, stress, trauma, or rapid growth, the body's demand for these amino acids can exceed its ability to produce them.

For instance, during periods of recovery from surgery or illness, the body may require higher amounts of certain amino acids like arginine and glutamine. In such cases, these amino acids must be obtained from the diet or supplements to meet the increased metabolic needs. This unique characteristic distinguishes them from essential amino acids, which must always be acquired through diet, and nonessential amino acids, which the body can produce independently under normal conditions. Complete amino acids, referring to those that provide all essential amino acids, do not address the concept of conditionality regarding the body's needs.