The word “nootropic” was coined in 1972 by a Romanian scientist, Corneliu Giurgea, who combined the Greek words for “mind” and “bending.” Caffeine and nicotine can be considered mild nootropics, while prescription Ritalin, Adderall and Provigil (modafinil, a drug for treating narcolepsy) lie at the far end of the spectrum when prescribed off-label as cognitive enhancers. Even microdosing of LSD is increasingly viewed as a means to greater productivity.
The U. S. nootropics industry was valued at more than $1.3 billion in 2015 and is projected to reach $6 billion by 2024. This growth is due in part to slick marketing from biohacking “experts” such as Dave Asprey (founder of Bulletproof) and Josiah Zayner, Ph.D. (CEO of the Odin), who’ve built big social-media and podcast followings as well as customer bases. At the grassroots level, there are meetups across the country like the one at Idea Coffee, plus a vibrant online community.

But according to Professor David Weinshenker of Emory University, most people who take Provigil do not report euphoria or even a level of stimulation close to the effects of caffeine. For Weinshenker, the addiction potential of Provigil is limited, and it’s used in various treatment contexts. Provigil may be an effective medication therapy for depression, ADHD, autism and other disorders.
Avocados. Avocados are almost as good as blueberries in promoting brain health, says Pratt. "I don't think the avocado gets its due," agrees Kulze. True, the avocado is a fatty fruit, but, says Kulze, it's a monounsaturated fat, which contributes to healthy blood flow. "And healthy blood flow means a healthy brain," she says. Avocados also lower blood pressure, says Pratt, and as hypertension is a risk factor for the decline in cognitive abilities, a lower blood pressure should promote brain health. Avocados are high in calories, however, so Kulze suggests adding just 1/4 to 1/2 of an avocado to one daily meal as a side dish.
(People aged <=18 shouldn’t be using any of this except harmless stuff - where one may have nutritional deficits - like fish oil & vitamin D; melatonin may be especially useful, thanks to the effects of screwed-up school schedules & electronics use on teenagers’ sleep. Changes in effects with age are real - amphetamines’ stimulant effects and modafinil’s histamine-like side-effects come to mind as examples.)
Gamma-aminobutyric acid, also known as GABA, naturally produced in the brain from glutamate, is a neurotransmitter that helps in the communication between the nervous system and brain. The main function of this Nootropic is to reduce the unnecessary activity of the nerve cells and helps calm the brain. . Thus it helps improve various conditions, like stress, anxiety and depression by decreasing the beta brain waves and increasing the alpha brain waves.  As a result, cognitive abilities like memory power, attention, and alertness also improve. GABA helps drug addicts recover from addiction by  normalizing the brain’s GABA receptors which reduce anxiety and craving levels in the absence of addictive substances.
That left me with 329 days of data. The results are that (correcting for the magnesium citrate self-experiment I was running during the time period which did not turn out too great) days on which I happened to use my LED device for LLLT were much better than regular days. Below is a graph showing the entire MP dataseries with LOESS-smoothed lines showing LLLT vs non-LLLT days:
I find this very troubling. The magnesium supplementation was harmful enough to do a lot of cumulative damage over the months involved (I could have done a lot of writing September 2013 - June 2014), but not so blatantly harmful enough as to be noticeable without a randomized blind self-experiment or at least systematic data collection - neither of which are common among people who would be supplementing magnesium I would much prefer it if my magnesium overdose had come with visible harm (such as waking up in the middle of the night after a nightmare soaked in sweat), since then I’d know quickly and surely, as would anyone else taking magnesium. But the harm I observed in my data? For all I know, that could be affecting every user of magnesium supplements! How would we know otherwise?
Racetams, such as piracetam, oxiracetam, and aniracetam, which are often marketed as cognitive enhancers and sold over-the-counter. Racetams are often referred to as nootropics, but this property is not well established.[31] The racetams have poorly understood mechanisms, although piracetam and aniracetam are known to act as positive allosteric modulators of AMPA receptors and appear to modulate cholinergic systems.[32]