Choline and L-phenylalanine share a similar role in the nervous system. They function as precursors for the production of several neurotransmitters. Neurotransmitters control the basic process of impulse transmission between nerve cells. They are responsible for an elevated and positive mood, alertness and ambition. A lack of them can cause depression.

A sufficient supply of choline must be present in the body to produce acetylcholine, an essential ingredient of nerve fluid. Acetylcholine makes it possible for impulses to be transmitted from one brain cell to the next and also from nerve cells to muscle cells. Acetylcholine is necessary for the correct functioning of the nervous system as well as for proper brain function.