Get B1 HCL 100-2000mg + NAD+ booster (Niagen) + Mg Threonate, that resolves inefficient energy metabolism in your brain/nerves that might cause the feeling of your brain being depleted (pseudohypoxia). Also, at your age L-Carnitine might be needed. Q10/Quercetin/Pterostilben/Bromelain/Betaine/NAC/R ALA/DCA might be worth considering depending on what other issues you face.