Your co-worker in the cubicle next to you could now very likely be achieving his or her hyperfocus via a touch of microdosed LSD, a hit of huperzine or a nicotine-infused arm patch. The fact is, concepts such as microdosing, along with words like “nootropic” and “smart drug” (yes, there’s a difference between the two, as you’re about to discover) are quickly becoming household terms, especially due to all the recent media hype that has disclosed how popular compounds such as smart drugs and psychedelics are among Silicon Valley CEOs and college students, along with the smart drug movies “Limitless” and “Lucy“ and popular TV shows like “Limitless”, “Wormwood” and “Hamilton’s Pharmacopeia”.
“By drawing on more than fifteen years of scientific research and experience, Dr. Mosconi provides expert advice to prevent medical decline and sharpen memory. Her brain healthy recipes will help you maintain peak cognitive performance well into old age and therefore delay and may even prevent the appearance of debilitating diseases like Alzheimer’s.”

There are a variety of substances to get magnesium from. Considerable enthusiasm for the new compound magnesium l-threonate was stirred by 2 small animal rat studies finding that magnesium l-threonate was able to increase magnesium levels in the brain and improve learning/memory tasks. (There are no published human trials as of October 2015, and evidence of publication bias, which I take as evidence against there being large effects in humans.) Animal studies mean very little, of course (see the appendix), but I thought it’d be interesting to try using l-threonate, so I bought the $30 Life Extension Neuro-Mag Magnesium L-Threonate with Calcium and Vitamin D3 (205g), which according to the LEF product page works out to ~60g of Magtein™ magnesium L-threonate and ~4.31g elemental magnesium inasmuch as LEF claims 2000mg of threonate powder provides 144mg elemental magnesium or a 14:1 ratio. (I don’t need the calcium or vitamin D3, but this was the only magnesium l-threonate on Amazon.) Experiment-wise, I’ll probably look at sleep metrics and Mnemosyne performance; I put off designing a blind self-experiment until after trying some.
The powder totals 227g of magnesium citrate, hence there is ~0.945g per magnesium citrate pill. The nutritional information states that it contains 119 servings of 0.315g magnesium elemental = 37.485g elemental, as expected, and so likewise there is 0.156g elemental magnesium per pill. This is the same dosage as the second half of the first magnesium citrate experiment (249 gel capsules there, 240 here), where the overdose effect seemed to also happen; so to avoid the overdosage, I will take one pill every other day to halve the dose to an average of ~0.078g/78mg elemental per day (piggybacking on the morning-caffeine experiment to make compliance easier).
Amongst the brain focus supplements that are currently available in the nootropic drug market, Modafinil is probably the most common focus drug used by people, and it’s actually touted to be the best nootropic available today.  It is a powerful cognitive enhancer that is great for boosting your overall alertness with least side effects.  However, to get your hands on this drug, you require a prescription.
The use of cognition-enhancing drugs by healthy individuals in the absence of a medical indication spans numerous controversial issues, including the ethics and fairness of their use, concerns over adverse effects, and the diversion of prescription drugs for nonmedical uses, among others.[1][2] Nonetheless, the international sales of cognition-enhancing supplements exceeded US$1 billion in 2015 when global demand for these compounds grew.[3]