Lecithin is a group of chemicals that are related. It isn't a single chemical. Lecithins belong to a larger group of compounds called phospholipids. These are important parts of the brain, blood, nerves, and other tissues. Phospholipids are also a part of cell membranes.
The body uses lecithin in the metabolic process and to move fats. Lecithins turn into choline in the body. They help make the neurotransmitter acetylcholine.
Lecithin is commonly used as a food additive to combine foods. Many people know lecithin as the oily film on their frying pan when they use a nonstick cooking spray.