Phosphatidylcholine (PC) is part of group of compounds called phospholipids. Phospholipids are essential components of cell membranes. PC acts as a supplier of choline, which is required for cell membrane integrity and to facilitate the movement of fats in and out of cells. It is also a component of the neurotransmitter acetylcholine, which is necessary for normal brain functioning. Although the human body can synthesize choline, additional amounts beyond what can be supplied by the diet are essential under certain circumstances. The liver utilizes choline as its primary source of fuel (triglycerides).