A fancier method of imputation would be multiple imputation using, for example, the R library mice (Multivariate Imputation by Chained Equations) (guide), which will try to impute all missing values in a way which mimicks the internal structure of the data and provide several possible datasets to give us an idea of what the underlying data might have looked like, so we can see how our estimates improve with no missingness & how much of the estimate is now due to the imputation:
When I worked on the Bulletproof Diet book, I wanted to verify that the effects I was getting from Bulletproof Coffee were not coming from modafinil, so I stopped using it and measured my cognitive performance while I was off of it. What I found was that on Bulletproof Coffee and the Bulletproof Diet, my mental performance was almost identical to my performance on modafinil. I still travel with modafinil, and I’ll take it on occasion, but while living a Bulletproof lifestyle I rarely feel the need.
But notice that most of the cost imbalance is coming from the estimate of the benefit of IQ - if it quadrupled to a defensible $8000, that would be close to the experiment cost! So in a way, what this VoI calculation tells us is that what is most valuable right now is not that iodine might possibly increase IQ, but getting a better grip on how much any IQ intervention is worth.

If you are in or are able to come to London, you may be interested in also coming to a one day workshop we are hosting with Patrick Holford, our founder and one the UK’s leading nutritional therapists. We are excited to be running this workshop, which enables our supporters to access Patrick’s wealth of knowledge on nutrition and mental health. More details can be found below. If you are outside of the UK and are interested in this workshop or learning more about nutrition and mental health, please sign up for news on our Seminar series here. 
And yet when enthusiasts share their vision of our neuroenhanced future it can sound dystopian. Zack Lynch, of NeuroInsights, gave me a rationale for smart pills that I found particularly grim. "If you're a 55-year-old in Boston, you have to compete with a 26-year-old from Mumbai now, and those kinds of pressures are only going to grow," he began. Countries other than the US might tend to be a little looser with their regulations and offer approval of new cognitive enhancers first. "And if you're a company that's got 47 offices worldwide, and all of a sudden your Singapore office is using cognitive enablers, and you're saying to Congress: 'I'm moving all my financial operations to Singapore and Taiwan, because it's legal to use those there', you bet that Congress is going to say: 'Well, OK.' It will be a moot question then.

The evidence? Ritalin is FDA-approved to treat ADHD. It has also been shown to help patients with traumatic brain injury concentrate for longer periods, but does not improve memory in those patients, according to a 2016 meta-analysis of several trials. A study published in 2012 found that low doses of methylphenidate improved cognitive performance, including working memory, in healthy adult volunteers, but high doses impaired cognitive performance and a person’s ability to focus. (Since the brains of teens have been found to be more sensitive to the drug’s effect, it’s possible that methylphenidate in lower doses could have adverse effects on working memory and cognitive functions.)
along with the previous bit of globalization is an important factor: shipping is ridiculously cheap. The most expensive S&H in my modafinil price table is ~$15 (and most are international). To put this in perspective, I remember in the 90s you could easily pay $15 for domestic S&H when you ordered online - but it’s 2013, and the dollar has lost at least half its value, so in real terms, ordering from abroad may be like a quarter of what it used to cost, which makes a big difference to people dipping their toes in and contemplating a small order to try out this ’nootropics thing they’ve heard about.
Most people I talk to about modafinil seem to use it for daytime usage; for me that has not ever worked out well, but I had nothing in particular to show against it. So, as I was capping the last of my piracetam-caffeine mix and clearing off my desk, I put the 4 remaining Modalerts pills into capsules with the last of my creatine powder and then mixed them with 4 of the theanine-creatine pills. Like the previous Adderall trial, I will pick one pill blindly each day and guess at the end which it was. If it was active (modafinil-creatine), take a break the next day; if placebo (theanine-creatine), replace the placebo and try again the next day. We’ll see if I notice anything on DNB or possibly gwern.net edits.
Because modafinil works in a manner similar to methylphenidate, it also bears similar risks. The improper dosage or abuse of modafinil may lead to the disrupted development of executive controls like decision-making and working memory. Modafinil’s effects may also depend upon the IQ of the taker. Two university studies determined that in a test of sustained attention, modafinil only improved cognition in the group with “lower” IQs. Although safer than other stimulants due to its milder effect on neurotransmitter levels, there are still risks associated with any kind of drug that affects dopaminergic neurotransmission, mostly because this can lead to addiction and, similar to a pornography user who needs increasingly fringe porn to achieve the same effect, can produce a resistance or lowered sensitivity to dopamine.
If you have spent any time shopping for memory enhancer pills, you have noticed dozens of products on the market. Each product is advertised to improve memory, concentration, and focus. However, choosing the first product promising results may not produce the desired improvements. Taking the time to research your options and compare products will improve your chances of finding a supplement that works.

Cytisine is not known as a stimulant and I’m not addicted to nicotine, so why give it a try? Nicotine is one of the more effective stimulants available, and it’s odd how few nicotine analogues or nicotinic agonists there are available; nicotine has a few flaws like short half-life and increasing blood pressure, so I would be interested in a replacement. The nicotine metabolite cotinine, in the human studies available, looks intriguing and potentially better, but I have been unable to find a source for it. One of the few relevant drugs which I can obtain is cytisine, from Ceretropic, at 2x1.5mg doses. There are not many anecdotal reports on cytisine, but at least a few suggest somewhat comparable effects with nicotine, so I gave it a try.
Finally, it’s not clear that caffeine results in performance gains after long-term use; homeostasis/tolerance is a concern for all stimulants, but especially for caffeine. It is plausible that all caffeine consumption does for the long-term chronic user is restore performance to baseline. (Imagine someone waking up and drinking coffee, and their performance improves - well, so would the performance of a non-addict who is also slowly waking up!) See for example, James & Rogers 2005, Sigmon et al 2009, and Rogers et al 2010. A cross-section of thousands of participants in the Cambridge brain-training study found caffeine intake showed negligible effect sizes for mean and component scores (participants were not told to use caffeine, but the training was recreational & difficult, so one expects some difference).

By the way, before we move on, allow me to clarify what I mean by “slow caffeine metabolizer”. Ever wondered why your co-worker can slam four giant mugs of coffee during a brief morning of work, while one shot of espresso leaves you jittery and irritated? Turns out that not everyone metabolizes caffeine the same. Generally speaking, in healthy adults, caffeine has a half-life that ranges from about 3 to 7 hours. For example, if the half-life of caffeine in your blood is 5 hours, that means that it takes 5 hours for caffeine levels to be reduced by 50%. Then it takes another 5 hours for that amount to be reduced by 50%. While caffeine metabolism time also depends upon age and environmental factors, a big influence on varying caffeine half-life times is your genetic makeup.

Nootropics, also known as ‘brain boosters’, or ‘cognitive enhancers’ are made up of a variety of artificial and natural compounds that help in enhancing the cognitive activities of the brain by regulating or altering the production of neurochemicals and neurotransmitters in the brain. It improves blood flow, stimulates neurogenesis (the process by which neurons are produced in the body by neural stem cells), enhances nerve growth rate, modifies synapses, and improves cell membrane fluidity. Thus, positive changes are created within your body, which helps you to function optimally; whatever be your current lifestyle and individual needs.
Regardless, while in the absence of piracetam, I did notice some stimulant effects (somewhat negative - more aggressive than usual while driving) and similar effects to piracetam, I did not notice any mental performance beyond piracetam when using them both. The most I can say is that on some nights, I seemed to be less easily tired when writing or editing or n-backing (and I felt less tired than ICON 2011 than ICON 2010), but those were also often nights I was also trying out all the other things I had gotten in that order from Smart Powders, and I am still dis-entangling what was responsible. (Probably the l-theanine or sulbutiamine.)
The advantage of adrafinil is that it is legal & over-the-counter in the USA, so one removes the small legal risk of ordering & possessing modafinil without a prescription, and the retailers may be more reliable because they are not operating in a niche of dubious legality. Based on comments from others, the liver problem may have been overblown, and modafinil vendors post-2012 seem to have become more unstable, so I may give adrafinil (from another source than Antiaging Central) a shot when my modafinil/armodafinil run out.
Before taking any supplement or chemical, people want to know if there will be long term effects or consequences, When Dr. Corneliu Giurgea first authored the term “nootropics” in 1972, he also outlined the characteristics that define nootropics. Besides the ability to benefit memory and support the cognitive processes, Dr. Giurgea believed that nootropics should be safe and non-toxic.
Kratom (Erowid, Reddit) is a tree leaf from Southeast Asia; it’s addictive to some degree (like caffeine and nicotine), and so it is regulated/banned in Thailand, Malaysia, Myanmar, and Bhutan among others - but not the USA. (One might think that kratom’s common use there indicates how very addictive it must be, except it literally grows on trees so it can’t be too hard to get.) Kratom is not particularly well-studied (and what has been studied is not necessarily relevant - I’m not addicted to any opiates!), and it suffers the usual herbal problem of being an endlessly variable food product and not a specific chemical with the fun risks of perhaps being poisonous, but in my reading it doesn’t seem to be particularly dangerous or have serious side-effects.
Still, putting unregulated brain drugs into my system feels significantly scarier than downing a latte or a Red Bull—not least because the scientific research on nootropics’ long-term effects is still so thin. One 2014 study found that Ritalin, modafinil, ampakines, and other similar stimulants could eventually reduce the “plasticity” of some of the brain’s neural networks by providing them with too much dopamine, glutamate and norepinephrine, and potentially cause long-term harm in young people whose brains were still developing. (In fact, in young people, the researchers wrote, these stimulants could actually have the opposite effect the makers intended: “Healthy individuals run the risk of pushing themselves beyond optimal levels into hyperdopaminergic and hypernoradrenergic states, thus vitiating the very behaviors they are striving to improve.”) But the researchers found no evidence that normal doses of these drugs were harmful when taken by adults.

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.
Brain Pill™ combines the most powerful, clinically proven ingredients on the forefront of brain productivity and memory research. Each of our carefully selected ingredients is potent and effective on its own, but together, our research goal was to create far and away the ultimate synergistic combination for enhancing mental clarity, alertness and overall brain function.
Your co-worker in the cubicle next to you could now very likely be achieving his or her hyperfocus via a touch of microdosed LSD, a hit of huperzine or a nicotine-infused arm patch. The fact is, concepts such as microdosing, along with words like “nootropic” and “smart drug” (yes, there’s a difference between the two, as you’re about to discover) are quickly becoming household terms, especially due to all the recent media hype that has disclosed how popular compounds such as smart drugs and psychedelics are among Silicon Valley CEOs and college students, along with the smart drug movies “Limitless” and “Lucy“ and popular TV shows like “Limitless”, “Wormwood” and “Hamilton’s Pharmacopeia”.
Nootropic (new-tro-pik) is the term for supplements, also known as smart drugs, that improve brain function. They can be food substances like phenethylamine and L-Theanine, found in chocolate and green tea, respectively. Nootropics also include extracted and purified components of medicinal plants, as well as substances synthesized from chemical precursors, such as piracetam, the world's first official nootropic (piracetam was created in 1964 in Belgium by a team of scientists whose leader, Dr. Corneliu E. Giurgea, coined the term). Since then piracetam has been widely used as a cognitive enhancer and to treat neurological diseases like Alzheimer's.
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."
Green tea is widely drunk in many cultures, especially in Asia, and is known to have potent health benefits. These benefits are attributed to its polyphenol content (particularly the flavanols and flavonols). In cell cultures and animal studies, the polyphenols have been proven to prevent neurotoxin-induced cell injury. Green tea also has anti-inflammatory properties and, according to a study performed on aged mice, may delay memory regression. It’s safe to drink several cups of green tea per day, though it may be more efficacious to take a green tea extract supplement to reach a daily dose of 400 to 500 mg of EGCG, one of the main active components of green tea.
Pre and Post-Natal Depression are both complex conditions that can have multifactorial underlying drivers, including genetic and environmental influences. These are currently poorly investigated and the gold standard of treatment is often medication to help stabilise mood. Whilst SSRIs and other types of antidepressants have proven to be helpful for many, they do not address potential causes or drivers of poor mental health and can often mask symptoms. Antidepressants are also not regularly recommended during pregnancy, which is why being more mindful of nutrition and lifestyle habits can be a safer option for you and your baby. There are some natural, evidence-based steps you can take to help support optimal mental wellbeing:

The real culprit at the heart of the problem may be impossible to regulate – the human desire to have a supercharged brain. For now, this wish is still largely relegated to the domain of fiction. Researchers point out that increasing the power of certain parts of the brain, such as areas responsible for learning and focus, would likely deprive other parts of the brain that are needed to live. Despite the appeal of a super-brain, a better goal is still to maintain a balanced brain and lifestyle.
It makes no sense to ban the use of neuroenhancers. Too many people are already taking them, and the users tend to be educated and privileged people who proceed with just enough caution to avoid getting into trouble. Besides, Anjan Chatterjee is right that there is an apt analogy with plastic surgery. In a consumer society like ours, if people are properly informed about the risks and benefits of neuroenhancers, they can make their own choices about how to alter their minds, just as they can make their own decisions about shaping their bodies.

My answer is that this is not a lot of research or very good research (not nearly as good as the research on nicotine, eg.), and assuming it’s true, I don’t value long-term memory that much because LTM is something that is easily assisted or replaced (personal archives, and spaced repetition). For me, my problems tend to be more about akrasia and energy and not getting things done, so even if a stimulant comes with a little cost to long-term memory, it’s still useful for me. I’m going continue to use the caffeine. It’s not so bad in conjunction with tea, is very cheap, and I’m already addicted, so why not? Caffeine is extremely cheap, addictive, has minimal effects on health (and may be beneficial, from the various epidemiological associations with tea/coffee/chocolate & longevity), and costs extra to remove from drinks popular regardless of their caffeine content (coffee and tea again). What would be the point of carefully investigating it? Suppose there was conclusive evidence on the topic, the value of this evidence to me would be roughly $0 or since ignorance is bliss, negative money - because unless the negative effects were drastic (which current studies rule out, although tea has other issues like fluoride or metal contents), I would not change anything about my life. Why? I enjoy my tea too much. My usual tea seller doesn’t even have decaffeinated oolong in general, much less various varieties I might want to drink, apparently because de-caffeinating is so expensive it’s not worthwhile. What am I supposed to do, give up my tea and caffeine just to save on the cost of caffeine? Buy de-caffeinating machines (which I couldn’t even find any prices for, googling)? This also holds true for people who drink coffee or caffeinated soda. (As opposed to a drug like modafinil which is expensive, and so the value of a definitive answer is substantial and would justify some more extensive calculating of cost-benefit.)
Nootropics can also show signs of neuro-preservation and neuro-protection. These compounds directly affect the levels of brain chemicals associated with slowing down the aging process. Some nootropics could in an increase in the production of Nerve Growth Factor and Brain-Derived Neurotrophic Factor to stimulate the growth of neurons and neurites while slowing down the rate of damage as well.
Factor analysis. The strategy: read in the data, drop unnecessary data, impute missing variables (data is too heterogeneous and collected starting at varying intervals to be clean), estimate how many factors would fit best, factor analyze, pick the ones which look like they match best my ideas of what productive is, extract per-day estimates, and finally regress LLLT usage on the selected factors to look for increases.
The beauty of this stack is that nature has already given us a perfectly packaged combination of caffeine and theanine in the form of green tea, whether a cup of green tea, a bowl of matcha tea, or even a green tea extract supplement as a substitute for a cup of coffee. This is an especially convenient stack to use during a time when you don’t want the excess stimulation of coffee or caffeine in isolation, such as during an evening dinner at a restaurant or in the latter stages of a workday when a cup of coffee might keep you awake too late into the night.
Capsule Connection sells 1000 00 pills (the largest pills) for $9. I already have a pill machine, so that doesn’t count (a sunk cost). If we sum the grams per day column from the first table, we get 9.75 grams a day. Each 00 pill can take around 0.75 grams, so we need 13 pills. (Creatine is very bulky, alas.) 13 pills per day for 1000 days is 13,000 pills, and 1,000 pills is $9 so we need 13 units and 13 times 9 is $117.
Like everything else in your body, the brain cannot work without energy. The ability to concentrate and focus comes from an adequate, steady supply of energy - in the form of glucose in our blood to the brain. Achieve this by choosing wholegrains with a low-GI, which release glucose slowly into the bloodstream, keeping you mentally alert throughout the day. Opt for 'brown' wholegrain cereals, granary bread, rice and pasta.
I took the pill at 11 PM the evening of (technically, the day before); that day was a little low on sleep than usual, since I had woken up an hour or half-hour early. I didn’t yawn at all during the movie (merely mediocre to my eyes with some questionable parts)23. It worked much the same as it did the previous time - as I walked around at 5 AM or so, I felt perfectly alert. I made good use of the hours and wrote up my memories of ICON 2011.
Takao Hensch, a Harvard professor of cellular biology and part of a Boston Children’s Hospital team, found that the drug encouraged the brain to learn new skills as quickly as the sponge-like brain of an infant in her patient Shannon, an otherwise normal 14-year-old girl who suffers from extremely poor eyesight brought on by amblyopia, commonly known as lazy eye. In a matter of months, the drug helped Shannon’s brain relearn how to use her eye which resulted in markedly improved vision.
“It is surprising and encouraging that it may be possible to predict the magnitude of a placebo effect before treatment,” says Tor Wager, a neuroscientist at the University of Colorado Boulder, who was not involved in the research. More work is needed to see how the predictive features hold up in other populations and for different pain conditions, he says.
The use of prescription stimulants is especially prevalent among students.[9] Surveys suggest that 0.7–4.5% of German students have used cognitive enhancers in their lifetime.[10][11][12] Stimulants such as dimethylamylamine and methylphenidate are used on college campuses and by younger groups.[13] Based upon studies of self-reported illicit stimulant use, 5–35% of college students use diverted ADHD stimulants, which are primarily intended for performance enhancement rather than as recreational drugs.[14][15][16] Several factors positively and negatively influence an individual's willingness to use a drug for the purpose of enhancing cognitive performance. Among them are personal characteristics, drug characteristics, and characteristics of the social context.[10][11][17][18]
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