NOW Alpha GPC - Alpha GPC (L-alpha-Glycerylphosphorylcholine) is a natural physiological precursor to acetyl-choline, a neurotransmitter that is involved in memory and other cognitive functions. Alpha GPC is more bioavailable than other forms of choline and is known to cross the blood brain barrier. In the brain and other neural tissues, Alpha GPC becomes a constituent of cell membranes. Clinical studies have demonstrated that supplementation with Alpha GPC can support the brain’s synthesis of acetyl-choline. In this way, it helps to promote normal cognitive function and mental acuity.