GLOSSARY

Phosphatidylserine is a serine-headed glycerophospholipid whose membrane distribution and movement between leaflets matter in cell signalling, not simply dietary amount.

Many common phospholipids have a phosphate-containing head and fatty tails that organise in water. Not all have a glycerol backbone: sphingomyelin is an important exception. Phospholipid names describe a structural family, not every attached fatty acid, its dietary quantity or the quality and effectiveness of a supplement claiming to contain it.

Head groups distinguish phospholipids: choline, ethanolamine, serine and inositol are not interchangeable substances. A group bound within a molecule is not equivalent to consuming the free substance with identical effects. In particular, ethanolamine is not beverage alcohol, and a serine head does not imply the same action as a free amino-acid supplement.

A polar region interacts more readily with water, whereas a nonpolar region avoids it; molecules with both are amphipathic. This enables lipid surfaces and membranes to form. Having no net charge does not necessarily mean being nonpolar: some phospholipid heads carry both positive and negative charges and remain strongly polar overall.

Claims that a PS supplement reduces stress or improves performance require evidence for that formulation; membrane membership alone is insufficient.

A membrane is not a static fatty wall: its lipid bilayer works with proteins, cholesterol and other components as a dynamic selective boundary. Lipid composition influences its properties, but changing one food does not instantly convert the entire membrane into that fat. Absorption, synthesis and tissue remodelling mediate dietary effects on membrane composition.

In a bilayer, water-friendly heads face the aqueous environments on both sides while hydrophobic tails meet inside. This differs from a triglyceride droplet or micelle. Cholesterol modulates membrane order and fluidity depending on temperature and composition; claiming that it always simply softens or always stiffens the membrane is inaccurate.

Egg yolk, soy and many edible tissues contain phospholipids alongside other nutrients. These molecules can be broken down and rebuilt during digestion and metabolism. Their presence in foods or the body does not establish a healthy athlete's need for a dedicated powder or capsule; memory, hormone or performance claims require suitable human evidence.