Phospholipid
A phospholipid is a fat molecule that carries a phosphate group. Glycerophospholipids are the main lipids in cell membranes; common examples include phosphatidylcholine, phosphatidylethanolamine and phosphatidylserine.
What it means in practice
A glycerophospholipid is built on glycerol, a small molecule with three carbon atoms. Two of those carbons each carry a fatty acid. The third carries a phosphate group, which can link to a head group; the head group gives the phospholipid its name, as in phosphatidylcholine or phosphatidylserine [1]. A cell membrane is a thin, water-repelling film, a lipid bilayer, that marks the boundary of the cell, and its two layers can differ in their lipid makeup [2]. Phosphatidylcholine and phosphatidylethanolamine are the most abundant phospholipids in all mammalian cell membranes [3]. Phosphatidylserine is the main negatively charged phospholipid and is concentrated in the inner layer of the cell membrane in nerve tissue [4].
Phospholipids are not fixed once made. Cells keep swapping their fatty acids, and different fatty acids change how the membrane behaves [1]. Omega-3 fatty acids such as DHA are among the fatty acids built into membrane phospholipids [5].
Why it matters when reading nootropics research
Several supplements on this site are phospholipids or their building blocks. Phosphatidylserine is itself a phospholipid [4]. A 2006 review, drawing mostly on rat data, describes uridine and cytidine as contributing to brain synthesis of phosphatidylcholine and phosphatidylethanolamine through the Kennedy pathway [6]. Eugene Kennedy and co-workers set out the general outline of many phospholipid-making pathways in the 1950s [3].
That a compound is a phospholipid, or feeds into making one, is a statement about chemistry. It does not by itself show that taking it changes memory, mood or anything else measured in people; each compound's page reports the human trials separately.
References
- Lamari F, Rossignol F, Mitchell GA. Glycerophospholipids: Roles in Cell Trafficking and Associated Inborn Errors. J Inherit Metab Dis. 2025.
- van Meer G, Voelker DR, Feigenson GW. Membrane lipids: where they are and how they behave. Nat Rev Mol Cell Biol. 2008.
- van der Veen JN, Kennelly JP, Wan S, et al. The critical role of phosphatidylcholine and phosphatidylethanolamine metabolism in health and disease. Biochim Biophys Acta Biomembr. 2017.
- Kim HY, Huang BX, Spector AA. Phosphatidylserine in the brain: metabolism and function. Prog Lipid Res. 2014.
- Hishikawa D, Valentine WJ, Iizuka-Hishikawa Y, et al. Metabolism and functions of docosahexaenoic acid-containing membrane glycerophospholipids. FEBS Lett. 2017.
- Cansev M. Uridine and cytidine in the brain: their transport and utilization. Brain Res Rev. 2006.