One claim was partially verified in passing by Eliezer Yudkowsky (Supplementing potassium (citrate) hasn’t helped me much, but works dramatically for Anna, Kevin, and Vassar…About the same as drinking a cup of coffee - i.e., it works as a perker-upper, somehow. I’m not sure, since it doesn’t do anything for me except possibly mitigate foot cramps.)
But Baldino may have been overly modest. In 2002, researchers at Cambridge University gave 60 healthy young male volunteers a battery of standard cognitive tests. One group received modafinil, the other a placebo. The modafinil group performed better on several tasks, such as the "digit span" test, in which subjects are asked to repeat increasingly longer strings of numbers forwards, then backwards. They also did better in recognising repeated visual patterns and at a spatial-planning challenge known as the Tower of London task. (It's not nearly as fun as it sounds.) Writing in the journal Psychopharmacology, the study's authors said the results suggested that "modafinil offers significant potential as a cognitive enhancer".
It’s a frosty Monday evening in March, but in the back of Idea Coffee, a dingy café near the Empire State Building, things are heating up. A group huddles around a small black box—the $160 ApeX Type A brain stimulator, with its retro-looking meter and dial and two electrodes. It’s supposed to bolster learning by delivering a mild electric current to the brain. The guy who’s been experimenting with it for a week notes that the only thing he’s noticed so far is a metallic taste in his mouth.
Because smart drugs like modafinil, nicotine, and Adderall come with drawbacks, I developed my own line of nootropics, including Forbose and SmartMode, that’s safe, widely available, and doesn’t require a prescription. Forskolin, found in Forbose, has been a part of Indian Ayurvedic medicine for thousands of years. In addition to being fun to say, forskolin increases cyclic adenosine monophosphate (cAMP), a molecule essential to learning and memory formation. [8]

On the plus side: - I noticed the less-fatigue thing to a greater extent, getting out of my classes much less tired than usual. (Caveat: my sleep schedule recently changed for the saner, so it’s possible that’s responsible. I think it’s more the piracetam+choline, though.) - One thing I wasn’t expecting was a decrease in my appetite - nobody had mentioned that in their reports.I don’t like being bothered by my appetite (I know how to eat fine without it reminding me), so I count this as a plus. - Fidgeting was reduced further

One of the other suggested benefits is for boosting serotonin levels; low levels of serotonin are implicated in a number of issues like depression. I’m not yet sure whether tryptophan has helped with motivation or happiness. Trial and error has taught me that it’s a bad idea to take tryptophan in the morning or afternoon, however, even smaller quantities like 0.25g. Like melatonin, the dose-response curve is a U: ~1g is great and induces multiple vivid dreams for me, but ~1.5g leads to an awful night and a headache the next day that was worse, if anything, than melatonin. (One morning I woke up with traces of at least 7 dreams, although I managed to write down only 2. No lucid dreams, though.)
In fact, this body-mind connection has become so relevant to our current era that communities like Mental Health America are devoting their efforts to create a challenge that raises awareness on how lifestyle plays an important role on our mental health. While our generation is definitely more conscious of our bodies and the importance of a healthy lifestyle, it's a good reminder that the body is like a machine and we should listen to it, tune it up, and update the system every so often. 
When you drink tea, you’re getting some caffeine (less than the amount in coffee), plus an amino acid called L-theanine that has been shown in studies to increase activity in the brain’s alpha frequency band, which can lead to relaxation without drowsiness. These calming-but-stimulating effects might contribute to tea’s status as the most popular beverage aside from water. People have been drinking it for more than 4,000 years, after all, but modern brain hackers try to distill and enhance the benefits by taking just L-theanine as a nootropic supplement. Unfortunately, that means they’re missing out on the other health effects that tea offers. It’s packed with flavonoids, which are associated with longevity, reduced inflammation, weight loss, cardiovascular health, and cancer prevention.
“In this fascinating investigation, Lisa Mosconi presents research that crosses disciplines to argue that what goes on in your brain—from your mood to your cognitive abilities—is very closely tied to what you put on your plate. In addition to being a compelling read, readers will find tips and outlines on ways they can change their diets for optimal brain health.”

However, normally when you hear the term nootropic kicked around, people really mean a “cognitive enhancer” — something that does benefit thinking in some way (improved memory, faster speed-of-processing, increased concentration, or a combination of these, etc.), but might not meet the more rigorous definition above.  “Smart drugs” is another largely-interchangeable term.

Noopept is a Russian stimulant sometimes suggested for nootropics use as it may be more effective than piracetam or other -racetams, and its smaller doses make it more convenient & possibly safer. Following up on a pilot study, I ran a well-powered blind randomized self-experiment between September 2013 and August 2014 using doses of 12-60mg Noopept & pairs of 3-day blocks to investigate the impact of Noopept on self-ratings of daily functioning in addition to my existing supplementation regimen involving small-to-moderate doses of piracetam. A linear regression, which included other concurrent experiments as covariates & used multiple imputation for missing data, indicates a small benefit to the lower dose levels and harm from the highest 60mg dose level, but no dose nor Noopept as a whole was statistically-significant. It seems Noopept’s effects are too subtle to easily notice if they exist, but if one uses it, one should probably avoid 60mg+.

The first night I was eating some coconut oil, I did my n-backing past 11 PM; normally that damages my scores, but instead I got 66/66/75/88/77% (▁▁▂▇▃) on D4B and did not feel mentally exhausted by the end. The next day, I performed well on the Cambridge mental rotations test. An anecdote, of course, and it may be due to the vitamin D I simultaneously started. Or another day, I was slumped under apathy after a promising start to the day; a dose of fish & coconut oil, and 1 last vitamin D, and I was back to feeling chipper and optimist. Unfortunately I haven’t been testing out coconut oil & vitamin D separately, so who knows which is to thank. But still interesting.

Omega-3 fatty acids: DHA and EPA – two Cochrane Collaboration reviews on the use of supplemental omega-3 fatty acids for ADHD and learning disorders conclude that there is limited evidence of treatment benefits for either disorder.[42][43] Two other systematic reviews noted no cognition-enhancing effects in the general population or middle-aged and older adults.[44][45]