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. 
Back home, I contacted Aubrey Marcus, whose company Onnit Labs produces Alpha Brain. He attributed my lucid dreaming to increased levels of the neurotransmitter acetylcholine, which enhances REM dreaming. Alpha Brain has two ingredients that boost acetylcholine levels: GPC choline, which the body converts to acetylcholine, and Huperzine A, an alkaloid derived from Chinese club moss, also known as Huperzia serrata. "Huperzine A disarms the enzyme that naturally breaks down acetylcholine," Marcus said. "So while the GPC choline is being converted to acetylcholine, the Huperzine A is keeping it from disappearing. It's like plugging the drain and turning on the faucet."
One should note the serious caveats here: it is a small in vitro study of a single category of human cells with an effect size that is not clear on a protein which feeds into who-knows-what pathways. It is not a result in a whole organism on any clinically meaningful endpoint, even if we take it at face-value (many results never replicate). A look at followup work citing Rapuri et al 2007 is not encouraging: Google Scholar lists no human studies of any kind, much less high-quality studies like RCTs; just some rat followups on the calcium effect. This is not to say Rapuri et al 2007 is a bad study, just that it doesn’t bear the weight people are putting on it: if you enjoy caffeine, this is close to zero evidence that you should reduce or drop caffeine consumption; if you’re taking too much caffeine, you already have plenty of reasons to reduce; if you’re drinking lots of coffee, you already have plenty of reasons to switch to tea; etc.
For obvious reasons, it’s difficult for researchers to know just how common the “smart drug” or “neuro-enhancing” lifestyle is. However, a few recent studies suggest cognition hacking is appealing to a growing number of people. A survey conducted in 2016 found that 15% of University of Oxford students were popping pills to stay competitive, a rate that mirrored findings from other national surveys of UK university students. In the US, a 2014 study found that 18% of sophomores, juniors, and seniors at Ivy League colleges had knowingly used a stimulant at least once during their academic career, and among those who had ever used uppers, 24% said they had popped a little helper on eight or more occasions. Anecdotal evidence suggests that pharmacological enhancement is also on the rise within the workplace, where modafinil, which treats sleep disorders, has become particularly popular.
Like caffeine, nicotine tolerates rapidly and addiction can develop, after which the apparent performance boosts may only represent a return to baseline after withdrawal; so nicotine as a stimulant should be used judiciously, perhaps roughly as frequent as modafinil. Another problem is that nicotine has a half-life of merely 1-2 hours, making regular dosing a requirement. There is also some elevated heart-rate/blood-pressure often associated with nicotine, which may be a concern. (Possible alternatives to nicotine include cytisine, 2’-methylnicotine, GTS-21, galantamine, Varenicline, WAY-317,538, EVP-6124, and Wellbutrin, but none have emerged as clearly superior.)
That’s why adults aren’t as crazy as teenagers, because adult brains aren’t as sensitive or reactive to external factors and experience teaches us to know better. That’s the potential danger with a drug like this. You return your brain to a state when you can learn a lot easier because you are ultra-sensitive to all stimuli in your environment, but it also makes it easier for that stimuli to affect you, for better or worse. The worst case scenario? You take this drug to be smarter but your personality can be destroyed by external stresses- it’s like being an emotional mess and losing yourself in high school again.
I noticed what may have been an effect on my dual n-back scores; the difference is not large (▃▆▃▃▂▂▂▂▄▅▂▄▂▃▅▃▄ vs ▃▄▂▂▃▅▂▂▄▁▄▃▅▂▃▂▄▂▁▇▃▂▂▄▄▃▃▂▃▂▂▂▃▄▄▃▆▄▄▂▃▄▃▁▂▂▂▃▂▄▂▁▁▂▄▁▃▂▄) and appears mostly in the averages - Toomim’s quick two-sample t-test gave p=0.23, although a another analysis gives p=0.138112. One issue with this before-after quasi-experiment is that one would expect my scores to slowly rise over time and hence a fish oil after would yield a score increase - the 3.2 point difference could be attributable to that, placebo effect, or random variation etc. But an accidentally noticed effect (d=0.28) is a promising start. An experiment may be worth doing given that fish oil does cost a fair bit each year: randomized blocks permitting an fish-oil-then-placebo comparison would take care of the first issue, and then blinding (olive oil capsules versus fish oil capsules?) would take care of the placebo worry.
Since my experiment had a number of flaws (non-blind, varying doses at varying times of day), I wound up doing a second better experiment using blind standardized smaller doses in the morning. The negative effect was much smaller, but there was still no mood/productivity benefit. Having used up my first batch of potassium citrate in these 2 experiments, I will not be ordering again since it clearly doesn’t work for me.
For example, a study published in the journal Psychopharmacology in 2000 found that ginkgo improved attention. A 2001 study in the journal Human Psychopharmacology suggested that it improves memory. Nevertheless, in a review of studies on ginkgo in healthy people, researchers found no good evidence that it improved mental abilities, according to a 2002 report in Psychopharmacology Bulletin.
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. 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.