Alpha-glycerylphosphorylcholine is the most bio available form of choline,and also has some mild nootropic effects.
It improves performance in both active and conditioning tasks in both young and old mice by increasing production of inositol phosphate, as well as increasing protein kinase C activity(an effect of other nootropics, such as oxiracetam), acetyl choline release, and nerve growth factor.
It has been effectively used to treat Alzheimers and increase recovery from stroke, and it also increases GH in both young and old humans.
The only problem with alpha-GPC at present is the cost. 1 gram is the recommended dosage, which was cost-prohibitive for most people, until now.