I would suggest the use of some (or all) of the following in a stack:
1) Acetyl-L-Carnitine Arginate (has an added molecule of arginine, making Acetyl-L-Carnitine considerably more potent than regular Carnitine; promotes the growth of neurites that enable communication among nerve cells in the brain; superior compound for optimal brain functioning)
2) Proprionyl-L-Carnitine (rapidly penetrates into heart, endothelial and muscle cells; delivers optimal energy metabolism in the mitochondria; maintains endothelial-wall integrity; combats muscle fatigue by enhancing muscle energy stores of glycogen; superior heart protector)
3) Phosphatidylserine (versatile compound in promoting brain health. Enhances availability of acetylcholine, reduces levels of the stress hormone cortisol, and supports the release of dopamine, an important neurotransmitter that promotes mood and movement coordination)
4) Mucuna Pruriens (standardized for L-Dopa, for enhancing dopamine levels)
5) GPC (glycerophosphocholine) (enhances acetylcholine synthesis and boosts memory function)
6) Vinpocetine (promotes brain metabolism and blood flow; may provide relief for vascular dementia and ischemic stroke)
7) Blueberries (inhibit memory impairment due to free radicals and beta-amyloid plaques in the brain)
8) Grape seed extract (protects brain cells from the toxic impact of oxidative stress and beta amyloid)
9) Pregnenolone (the most powerful memory enhancer known to science. Supports nerve cell growth in the brain’s memory center and supports the release of acetylcholine)
10) Ashwagandha (delivers brain protection via stress relief)
11) Ginkgo Biloba and Moega-3 Fatty Acids (deliver superior memory and cognition enhancement)
This list is, of course, incomplete!