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).
Can brain enhancing pills actually improve memory? This is a common question and the answer varies, depending on the product you are considering. The top 25 brain enhancement supplements appear to produce results for many users. Research and scientific studies have demonstrated the brain boosting effects of nootropic ingredients in the best quality supplements. At Smart Pill Guide, you can read nootropics reviews and discover how to improve memory for better performance in school or at work.
As a general class, nootropics are not usually addiction-forming.[6] Two of the strongest hallmarks of addiction-forming drugs is that they cause users to develop dependency and experience withdrawal when the drug use is eliminated or reduced. While there are some reports of nootropic users experiencing brain fog after use is discontinued, these side effects are not considered to be akin to withdrawal effects of addiction-forming drugs.[7]

According to Dr. Cohen, there’s no incentive for these companies to conduct trials to determine if their products actually do anything, so few of them do. In fact, he says he isn’t aware of any studies on nootropics that meet the research gold standard: double-blind, placebo-controlled, comparing meaningful numbers of healthy adults (not laboratory mice or rats) in terms of relevant measures of cognitive enhancement.

One thing I did do was piggyback on my Noopept self-experiment: I blinded & randomized the Noopept for a real experiment, but simply made sure to vary the Magtein without worrying about blinding or randomizing it. (The powder is quite bulky.) The correlation the experiment turned in was a odds-ratio of 1.9; interesting and in the right direction (higher is better), but since the magnesium part wasn’t random or blind, not a causal result.
The hormone testosterone (; FDA adverse events) needs no introduction. This is one of the scariest substances I have considered using: it affects so many bodily systems in so many ways that it seems almost impossible to come up with a net summary, either positive or negative. With testosterone, the problem is not the usual nootropics problem that that there is a lack of human research, the problem is that the summary constitutes a textbook - or two. That said, the 2011 review The role of testosterone in social interaction (excerpts) gives me the impression that testosterone does indeed play into risk-taking, motivation, and social status-seeking; some useful links and a representative anecdote:
People with failing memory and worried about Alzheimer’s disease are sometimes seduced by advertisements for Huperzine A, extracted from a type of moss. Some studies have shown that it increases levels of acetylcholine in the brain, a chemical that is in short supply in Alzheimer’s. But despite increasing acetylcholine, aside from a few questionable studies in China, there is no evidence that it improves memory. Unfortunately when it comes to memory pills, they are best forgotten. There is, however, hope that a nasal spray containing insulin can increase the absorption of glucose into brain cells and improve cognitive function. But in the meantime, the best bet to maintain good brain function is to monitor blood glucose and blood pressure, eat a diet rich in fruits, vegetables and whole grains, and low in simple carbs and saturated fat. And don’t forget that physical exercise also exercises your brain.
The drug methylphenidate is marketed as the brand Ritalin and used to treat children and adults with ADHD. As of 2011, according to the U.S. Centers for Disease Control and Prevention, 11 percent of Americans aged 4-17 were diagnosed with ADHD.[13] The high number of people diagnosed with ADHD means that there is a vast amount of prescription drugs to treat this condition in medicine cabinets across the US. Ultimately, some of these drugs get diverted into the hands of non-prescribed users, such as college students who believe they may be able to improve their studying and performance on exams by taking these drugs.
Caffeine, the mild stimulant found in coffee, improves mental acuity, though the drink's enthusiasts -- who guzzle 120,000 tons of the stuff each year -- likely already know that. Aside from caffeine's brain boosting effects, coffee's antioxidant richness helps maintain brain health. And some research suggests that drinking coffee can actually stave off depression in women.

Phillips told me that, much as he believes in neuroenhancers, he did not want to be "the poster boy for smart-in-a-pill". At one point, he said: "We really don't know the possible implications for long-term use of these things." (He recently stopped taking Provigil every day, replacing it with another prescription stimulant.) Nor does he think we need to be turning up the crank another notch on how hard we work. "But," he said, "the baseline competitive level is going to reorientate around what these drugs make possible, and you can choose to compete or not."

Apart from the risks that accompany drugs with dopaminergic effects, amphetamines, even when used to treat neurological disorders like ADHD, have been known to frequently and predictably cause anorexia, weight loss and insomnia. High doses can cause psychotic behavior, and even normal doses have been known to produce psychosis that ranged from the loss of short-term memory to horrific visual and auditory hallucinations. Are you getting the impression that using synthetic stimulants to flood your brain short-term with excessive or unnaturally high levels of hormones and neurotransmitters may not be a good idea, especially when done frequently or in excess?

I do recommend a few things, like modafinil or melatonin, to many adults, albeit with misgivings about any attempt to generalize like that. (It’s also often a good idea to get powders, see the appendix.) Some of those people are helped; some have told me that they tried and the suggestion did little or nothing. I view nootropics as akin to a biological lottery; one good discovery pays for all. I forge on in the hopes of further striking gold in my particular biology. Your mileage will vary. All you have to do, all you can do is to just try it. Most of my experiences were in my 20s as a right-handed 5’11 white male weighing 190-220lbs, fitness varying over time from not-so-fit to fairly fit. In rough order of personal effectiveness weighted by costs+side-effects, I rank them as follows:
Eugeroics (armodafinil and modafinil) – are classified as "wakefulness promoting" agents; modafinil increased alertness, particularly in sleep deprived individuals, and was noted to facilitate reasoning and problem solving in non-ADHD youth.[23] In a systematic review of small, preliminary studies where the effects of modafinil were examined, when simple psychometric assessments were considered, modafinil intake appeared to enhance executive function.[27] Modafinil does not produce improvements in mood or motivation in sleep deprived or non-sleep deprived individuals.[28]