Nootropics and Intelligence
Everyone wishes they could be smarter. After all, our intelligence affects almost every aspect of our lives. Whether it is performing well in school, trying to get promoted at work, or guessing how a movie is going to end, our intelligence plays a role. If you could increase your intelligence wouldn’t you do it? Maybe it would depend on the consequences. Some people would give up a lot to improve their intelligence, others not so much. But if there were no consequences, then why not?
Asking whether you would choose to improve your intelligence isn’t the important question. The real question you should be asking is, “Can you improve your intelligence, and if so to what extent?” Even though studies have shown that IQ heritability can be as high as .8 by adulthood (meaning there is little variation between the parent’s and offspring’s IQ), that doesn’t mean your intelligence can’t be improved or changed. 
It is certainly possible to lower your intelligence by abusing harmful drugs such as alcohol, cocaine, methamphetamines, and ecstasy; so wouldn’t it hold true that other drugs may improve your intelligence? A study published in 2008 stated, “Fluid intelligence is trainable to a significant and meaningful degree”.  The verdict is in, even though genetics may set the starting point for your intelligence, you can make a meaningful improvement to it on your own.
Types of Intelligence
Before we talk about how you can actually improve your intelligence it is important that you can distinguish between the different types.
This type of intelligence refers to the knowledge and skills that are accumulated over a lifetime. In other words, it refers to someone’s breadth of general knowledge. Usually the older someone is, the higher their crystallized intelligence is, though this is not always the case. People who are always making an effort to try new things and learn new things will have a higher crystallized intelligence.
The main way you can improve this type of intelligence is by making an effort. Learn a new skill or watch the history channel. However, that’s not the only way. Crystallized intelligence is affected by your long term memory. The better your brain stores information, the easier it is to accumulate it. It is very possible to improve your memory with the help of nootropics. However, chances are this isn’t the type of intelligence you are trying to improve.
Unlike crystallized intelligence, fluid intelligence doesn’t depend on the accumulation of knowledge. Fluid intelligence refers to one’s ability to learn, reason, think logically/abstractly, and solve problems. Think of crystallized intelligence as the pieces to a puzzle, and fluid intelligence as the ability to quickly and easily put those pieces together. No matter how high your fluid intelligence is, if you don’t know what the parts to a particular problem are, you won’t be able to solve it.
For example, someone with a high fluid intelligence but no crystallized intelligence in the field of accounting wouldn’t be able to figure out why the books don’t balance. It doesn’t matter how good they are at solving problems, everything would look like a foreign language to them.
Unlike crystalized intelligence, which improves with age, fluid intelligence peaks during young adulthood and steadily declines with age.  This is the type of intelligence people want to not only improve, but also keep from declining. So how can you do it?
Improving Fluid Intelligence
Not only is improving your fluid intelligence possible but it might be easier than you think.  Over the past five years there have been a surge of studies published which state that working memory and fluid intelligence are very closely related and that by improving your working memory you can improve your fluid intelligence. 
Working memory, more commonly referred to as short-term memory, is responsible for temporarily maintaining and manipulating information during various cognitive activities. When you think about it, it makes sense that improving your working memory would also improve your fluid intelligence. Let’s go back to the puzzle example. If fluid intelligence is your ability to put together puzzle pieces, your working memory is your ability to not only keep track of more pieces for a longer period of time, but also manipulate those pieces to see if they fit.
It would make sense that if you can hold more parts to a problem in your head, try a solution in your head, keep track of that solution, and try another solution, you would be able to solve the problem more effectively. A study conducted in 2010 found that a child’s working memory at 5 years of age is a better predictor of academic success than their IQ.  I already know what your next question is. How do I improve my working memory?
The part about encoding/storage explains how memories are encoded, stored for the short term, and how you can improve that process but I will provide a brief summary here.
Working Memory and How to Improve It
Your neuron synapses permit a neuron to pass a neurotransmitter from one neuron to another where they are received via receptors. From there, the electrochemical signal is conducted via dendrites. In simpler terms, your brain needs neuron synapses to communicate. Without a synapse, your neuron cannot dispel any neurotransmitters.
Interestingly, these neuron synapses are not static. They are always changing. New ones can be formed, strengthened, weakened, or destroyed. Your brain’s ability to manipulate these connections is referred to as synaptic plasticity. Having a greater level of synaptic plasticity improves your working memory.  The more connections that you brain can form, the more puzzle pieces your brain can hold and manipulate. It is no coincidence that most nootropics which improve short term memory also improve one’s ability to reason and problem solve.
Nootropics that improve fluid intelligence/working memory by improving synaptic plasticity include:
There is also evidence to suggest that regulation of the neurotransmitters, acetylcholine, norepinephrine and dopamine may improve working memory.  A further study suggested that dopamine only affected the reward expectancy while norepinephrine was directly involved in the maintenance of information and improvement of working memory. Like the research suggests, certain nootropics that regulate acetylcholine and norepinephrine levels have been linked to an improved working memory and improved fluid intelligence.
Nootropics that improve fluid intelligence/working memory by norepinephrine or acetylcholine production include:
- Ashwagandha – Increases levels of acetylcholine
- Huperzia Serrata – Increases levels of acetylcholine
- Galantamine – Increases levels of acetylcholine
- DMAE – Increases levels of acetylcholine
- Centrophenoxine – Increase levels of acetylcholine
- Tyrosine – Increases levels of norepinephrine
- Pyritinol – Increases levels of norepinephrine
- Iodine – Increases levels of norepinephrine
Which Nootropics Work Best?
Studies and anecdotal evidence seem to say that the nootropics which improve synaptic plasticity have the greatest effect on fluid intelligence and learning. In particular, many people have good things to say about the “racetam” nootropics. There are also nootropics which increase plasticity and levels of acetylcholine such as Ashwagandha and Huperzia Serrata. If you are looking to build a regimen around improving intelligence I would suggest a nootropic that improves plasticity, a nootropic that increases acetylcholine levels, and a nootropic that increases norepinephrine levels.
Read through the articles on this site and decide which ones might work best for you. Even though many have similar effects, side effects may vary. Some are also natural while others are synthetic. Remember that nootropics affect everyone differently. What may work well for someone else may not work as well for you.
 Sternberg, R. J. (2008). “Increasing fluid intelligence is possible after all”. Proceedings of the National Academy of Sciences 105 (19): 6791–2. doi:10.1073/pnas.0803396105. PMC 2383939. PMID 18474863. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2383939.
 Cavanaugh, J.C., & Blanchard-Fields, F (2006). Adult development and aging (5th ed.) Belmont, CA: Wadsworth Publishing/Thomson Learning. ISBN 0534520669.
 Kyllonen, P. C., & Christal, R. E. (1990). “Reasoning ability is (little more than) working-memory capacity?!” Intelligence, 14, 389–433.
 “Improving Fluid Intelligence with training on working memory” (2008) http://www.pnas.org/content/105/19/6829.full
 “Working memory, fluid intelligence, and science learning” (2006) http://www.stanford.edu/dept/SUSE/SEAL/Reports_Papers/YuanEtal_WorkingMemory.pdf
 Alloway TP, Alloway RG (2010). “Investigating the predictive roles of working memory and IQ in academic attainment”. Journal of Experimental Child Psychology 80 (2): 606–21. doi:10.1016/j.jecp.2009.11.003. PMID 20018296.
 “Spike-timing Theory of Working Memory” http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1000879
 “Boosting Working Memory” http://www.sciencemag.org/content/290/5500/2275.full
 “Noradrenaline and dopamine elevation in the rat prefrontal cortex in spatial working memory” http://www.ncbi.nlm.nih.gov/pubmed/15745958