Clinical psychiatrist Emily Deans has a private practice in Massachusetts and teaches at Harvard Medical School. She told me by phone that, in principle, there's "probably nothing dangerous" about the occasional course of nootropics for a hunting trip, finals week, or some big project. Beyond that, she suggests considering that it's possible to build up a tolerance to many neuroactive products if you use them often enough.
SOURCES: Ray Sahelian, MD. Psychopharmacology, September 2000. Human Psychopharmacology, July 2001; January 2002. Psychopharmacology Bulletin, Summer 2002. The Cochrane Database of Systematic Reviews, 2002. Archives of Neurology, November 1998. Zhongguo Yao Li Xue Bao, July 1999. Pharmacological Research, September 1999. International Clinical Psychopharmacology, March 2003. FDA web site.
In 2011, a story surfaced that struck fear into many: A woman was being treated for brain and memory disorders, when in reality she was just incredibly low in B12 stores. Turns out, this isn’t uncommon; many physicians don’t run routine blood tests for the nutrient, which is especially troublesome considering that our ability to absorb B12 is dramatically reduced with age. Over time, low vitamin B12 can do a number of your cognition.
As discussed in my iodine essay (FDA adverse events), iodine is a powerful health intervention as it eliminates cretinism and improves average IQ by a shocking magnitude. If this effect were possible for non-fetuses in general, it would be the best nootropic ever discovered, and so I looked at it very closely. Unfortunately, after going through ~20 experiments looking for ones which intervened with iodine post-birth and took measures of cognitive function, my meta-analysis concludes that: the effect is small and driven mostly by one outlier study. Once you are born, it’s too late. But the results could be wrong, and iodine might be cheap enough to take anyway, or take for non-IQ reasons. (This possibility was further weakened for me by an August 2013 blood test of TSH which put me at 3.71 uIU/ml, comfortably within the reference range of 0.27-4.20.)
There's no magic bullet to boost IQ or make you smarter -- but certain substances, like caffeine, can energize you and help you concentrate. Found in coffee, chocolate, energy drinks, and some medications, caffeine gives you that unmistakable wake-up buzz, though the effects are short-term. And more is often less: Overdo it on caffeine and it can make you jittery and uncomfortable.

But, thanks to the efforts of a number of remarkable scientists, researchers and plain-old neurohackers, we are beginning to put together a “whole systems” model of how all the different parts of the human brain work together and how they mesh with the complex regulatory structures of the body. It’s going to take a lot more data and collaboration to dial this model in, but already we are empowered to design stacks that can meaningfully deliver on the promise of nootropics “to enhance the quality of subjective experience and promote cognitive health, while having extremely low toxicity and possessing very few side effects.” It’s a type of brain hacking that is intended to produce noticeable cognitive benefits.
"Over the years, I have learned so much from the work of Dr. Mosconi, whose accomplished credentials spanning both neuroscience and nutrition are wholly unique. This book represents the first time her studies on the interaction between food and long-term cognitive function reach a general audience. Dr. Mosconi always makes the point that we would eat differently and treat our brains better if only we could see what we are doing to them. From the lab to the kitchen, this is extremely valuable and urgent advice, complete with recommendations that any one of us can take."
Spaced repetition at midnight: 3.68. (Graphing preceding and following days: ▅▄▆▆▁▅▆▃▆▄█ ▄ ▂▄▄▅) DNB starting 12:55 AM: 30/34/41. Transcribed Sawaragi 2005, then took a walk. DNB starting 6:45 AM: 45/44/33. Decided to take a nap and then take half the armodafinil on awakening, before breakfast. I wound up oversleeping until noon (4:28); since it was so late, I took only half the armodafinil sublingually. I spent the afternoon learning how to do value of information calculations, and then carefully working through 8 or 9 examples for my various pages, which I published on Lesswrong. That was a useful little project. DNB starting 12:09 AM: 30/38/48. (To graph the preceding day and this night: ▇▂█▆▅▃▃▇▇▇▁▂▄ ▅▅▁▁▃▆) Nights: 9:13; 7:24; 9:13; 8:20; 8:31.
However, they fell short in several categories. The key issue with their product is that it does not contain DHA Omega 3 and the other essential vitamins and nutrients needed to support the absorption of Huperzine A and Phosphatidylserine. Without having DHA Omega 3 it will not have an essential piece to maximum effectiveness. This means that you would need to take a separate pill of DHA Omega 3 and several other essential vitamins to ensure you are able to reach optimal memory support. They also are still far less effective than our #1 pick’s complete array of the 3 essential brain supporting ingredients and over 30 supporting nutrients, making their product less effective.
Another promising "smart pill" is phosphatidylserine, or PS, a natural substance that helps cell walls stay pliable and is thought to boost the effectiveness of neurotransmitters, which relay brain signals. In a May 1991 study published in Neurology, neuroscientist Thomas Crook found that patients with age-associated memory impairment improved their scores on key performance tests after 12 weeks on PS. Yet more research is needed before doctors can know that the supplement is safe and effective.
l-Theanine – A 2014 systematic review and meta-analysis found that concurrent caffeine and l-theanine use had synergistic psychoactive effects that promoted alertness, attention, and task switching;[29] these effects were most pronounced during the first hour post-dose.[29] However, the European Food Safety Authority reported that, when L-theanine is used by itself (i.e. without caffeine), there is insufficient information to determine if these effects exist.[34]