2 commenters point out that my possible lack of result is due to my mistaken assumption that if nicotine is absorbable through skin, mouth, and lungs it ought to be perfectly fine to absorb it through my stomach by drinking it (rather than vaporizing it and breathing it with an e-cigarette machine) - it’s apparently known that absorption differs in the stomach.
Recent findings also suggest that taking extra vitamins could help preserve memory, especially as we age. Researchers at Australia's University of Sydney tested 117 people in a retirement home by putting them through a battery of mental tests that included remembering a string of words, listing as many words as possible that begin with a certain letter of the alphabet, and doing mental addition and subtraction. Those who regularly took vitamin C, they found, scored higher on the tests.
That first night, I had severe trouble sleeping, falling asleep in 30 minutes rather than my usual 19.6±11.9, waking up 12 times (5.9±3.4), and spending ~90 minutes awake (18.1±16.2), and naturally I felt unrested the next day; I initially assumed it was because I had left a fan on (moving air keeps me awake) but the new potassium is also a possible culprit. When I asked, Kevin said:
Brain Pill™ is a mental health enhancing and successfully marketed dietary supplement with a balanced composition of scientifically proven nutrients for accelerating and restoring brain function and thereby enhancing the cognitive performance and creating positive impact on behavioral outcomes.Hence the aim of the study is assessment of the effects of Brain Pill supplementation on memory performance in healthy adults with subjective memory complaints.
Nuts and seeds. Nuts and seeds are good sources of vitamin E, says Pratt, explaining that higher levels of vitamin E correspond with less cognitive decline as you get older. Add an ounce a day of walnuts, hazelnuts, Brazil nuts, filberts, almonds, cashews, peanuts, sunflower seeds, sesame seeds, flax seed, and unhydrogenated nut butters such as peanut butter, almond butter, and tahini. Raw or roasted doesn't matter, although if you're on a sodium-restricted diet, buy unsalted nuts.

It is important that this type of approach is discussed with a qualified health professional, such as a registered nutritional therapist, to ensure it is an appropriate strategy for you, as well as to help you avoid missing out on vital nutrients, whilst eliminating certain foods. They can also provide advice on improving your longer term health, which over time may allow for foods to be reintroduced without negative symptoms occurring.

Clarke and Sokoloff (1998) remarked that although [a] common view equates concentrated mental effort with mental work…there appears to be no increased energy utilization by the brain during such processes (p. 664), and …the areas that participate in the processes of such reasoning represent too small a fraction of the brain for changes in their functional and metabolic activities to be reflected in the energy metabolism of the brain… (p. 675).
Here’s how it works: Donepezil boosts serotonin and acetylcholine in the brain, chemicals that are usually found in high concentrations in the brains of young children which naturally decrease with age. As a cholinesterase inhibitor, Donezepil boosts brain function by increasing the amount of acetylcholine around nerve endings. In dementia and Alzheimer’s patients, the drug has been shown to improve memory function.
The difference in standard deviations is not, from a theoretical perspective, all that strange a phenomenon: at the very beginning of this page, I covered some basic principles of nootropics and mentioned how many stimulants or supplements follow a inverted U-curve where too much or too little lead to poorer performance (ironically, one of the examples in Kruschke 2012 was a smart drug which did not affect means but increased standard deviations).

While the primary effect of the drug is massive muscle growth the psychological side effects actually improved his sanity by an absurd degree. He went from barely functional to highly productive. When one observes that the decision to not attempt to fulfill one’s CEV at a given moment is a bad decision it follows that all else being equal improved motivation is improved sanity.

Speaking of addictive substances, some people might have considered cocaine a nootropic (think: the finance industry in Wall Street in the 1980s). The incredible damage this drug can do is clear, but the plant from which it comes has been used to make people feel more energetic and less hungry, and to counteract altitude sickness in Andean South American cultures for 5,000 years, according to an opinion piece that Bolivia’s president, Evo Morales Ayma, wrote for the New York Times.
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).
The Neurohacker Collective is a group of scientists, academics, and creatives who, among other things, sell nootropics. One of its premier products is Qualia Original Stack (OS), which has 41 ingredients. The large print says it improves focus, mood, and energy within 30 minutes and “supports long-term brain health.” A 22-dose supply costs $129. Such stacks operate on the idea that synergies among ingredients yield additional benefits.
“We didn’t see significant long-term effects from the dosage used,” said Wen-Jun Gao, a professor of neurobiology at the Drexel University College of Medicine, and one of the authors of the study. He added that the brain doesn’t fully stop developing until age 25 or 30, making cognitive enhancement potentially risky even for users who are well into adulthood.

Mercury, as well as other heavy metals such as lead, can accumulate in brain tissue, as well as in the spinal cord, as they are fat-soluble - meaning that they can hide itself in fat tissue, which is abundant in both the brain and the spine. Once there, they can displace important nutrients for brain health such as zinc and iron, which are needed for neurotransmitter production, as well as induce an inflammatory process called oxidative stress among other things.
As a result of her years of research in this area, Dr. Lisa proposes a variety of foods that lead to better cognitive functioning and those which, in contrast, minimize cognitive functioning. "The best four foods one can consume to boost brain power are fish, dark leafy green veggies, berries, and water," she explains. And the worst? "Fast food, processed foods and poor quality meat." 

Common issues such as poor sleep during pregnancy and sleep deprivation following the birth can often heighten cravings for stimulants and sugary foods, which may seem like a good option for quick sources of energy, however, these foods can often cause further issues with energy and lead to fatigue and low mood. Eating foods that are high in refined sugar and refined grains such as commercial white bread, pastries, cakes and biscuits, give us an unsustainable source of energy. The brain is a very metabolically active organ; despite it only being 7% of the body’s weight, it can take up to 20% of the body’s metabolic needs (2), meaning that it is very energy hungry. This is why it is important to nourish the brain with foods that are nutrient rich, providing the body the building blocks to produce neurotransmitters, as well as a sustainable source of energy. The best options are fresh, unprocessed foods such as wholegrains (brown bread, brown rice, quinoa, rye and oats), pulses, vegetables, good quality sources of protein (meat, poultry and fish) and healthy fats such as those found in olive oil, coconut oil, avocados and oily fish. 
Spinach is rich in the antioxidant lutein, which is thought to help protect against cognitive decline, according to researchers from Tufts University. And a longitudinal study at Harvard Medical School found that women who reported eating the most leafy green and cruciferous vegetables had a markedly lower rate of cognitive decline, compared to those who ate the least.
You’ve no doubt heard that we’re now entering a new golden age of psychedelics, and microdosing with LSD, psilocybin, ketamine and other compounds previously placed in the realm of party animals and rave enthusiasts is now commonplace for CEO’s, the Navy SEALs, famous authors and beyond. You no longer have to be a tree-hugging, anti-war rebel to achieve the many positive health benefits of psychedelics. My own personal experience with these compounds has spanned several years of quarterly heavy psilocybin and DMT dosages for personal self-discovery, weekly LSD microdoses for creativity and productivity, and iboga microdosing for a pre-workout boost.
Jump up ^ Greely, Henry; Sahakian, Barbara; Harris, John; Kessler, Ronald C.; Gazzaniga, Michael; Campbell, Philip; Farah, Martha J. (December 10, 2008). "Towards responsible use of cognitive-enhancing drugs by the healthy". Nature. Nature Publishing Group. 456 (7223): 702–705. Bibcode:2008Natur.456..702G. doi:10.1038/456702a. ISSN 1476-4687. OCLC 01586310. PMID 19060880. Retrieved March 25, 2014. (Subscription required (help)).