For the moment, people looking for that particular quick fix have a limited choice of meds. But given the amount of money and research hours being spent on developing drugs to treat cognitive decline, Provigil and Adderall are likely to be joined by a bigger pharmacopoeia. Among the drugs in the pipeline are ampakines, which target a type of glutamate receptor in the brain; it is hoped that they may stem the memory loss associated with diseases like Alzheimer's. But ampakines may also give healthy people a palpable cognitive boost. A 2007 study of 16 healthy elderly volunteers found that 500mg of one particular ampakine "unequivocally" improved short-term memory, though it appeared to detract from episodic memory - the recall of past events. Another class of drugs, cholinesterase inhibitors, which are already being used with some success to treat Alzheimer's patients, have also shown promise as neuroenhancers. In one study the drug donepezil strengthened the performance of pilots on flight simulators; in another, of 30 healthy young male volunteers, it improved verbal and visual episodic memory. Several pharmaceutical companies are working on drugs that target nicotine receptors in the brain in the hope that they can replicate the cognitive uptick that smokers get from cigarettes.
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.
Difficulty concentrating.  As mentioned previously, this may not be a direct result of age—though it can be a common side-effect of struggling with fatigue and brain fog.  When it takes more mental energy to think, it is harder to stay with it for a long time.  Many of us also are surrounded by distractions clambering for our limited attention.  Modern life is fast-paced, stressful, and overcrowded.
On the plus side: - I noticed the less-fatigue thing to a greater extent, getting out of my classes much less tired than usual. (Caveat: my sleep schedule recently changed for the saner, so it’s possible that’s responsible. I think it’s more the piracetam+choline, though.) - One thing I wasn’t expecting was a decrease in my appetite - nobody had mentioned that in their reports.I don’t like being bothered by my appetite (I know how to eat fine without it reminding me), so I count this as a plus. - Fidgeting was reduced further
The evidence? Although everyone can benefit from dietary sources of essential fatty acids, supplementation is especially recommended for people with heart disease. A small study published in 2013 found that DHA may enhance memory and reaction time in healthy young adults. However, a more recent review suggested that there is not enough evidence of any effect from omega 3 supplementation in the general population.
Another traditional Chinese brain booster is Danggui-Shaoyao-San (DSS). It has been suggested that DSS has potent beneficial angiogenesis and neurogenesis effects that may make it a potential treatment for ischemic stroke therapy. DSS is also known to beneficially impact free radical-mediated neurological diseases, exhibit anti-inflammatory and antioxidant activities and reduce cell death in the hippocampus, thereby promoting greater emotional, memory-related and autonomic nervous system function. Currently, there is limited research on proper dosage, but you can learn more about DSS in this fantastic summary article on it’s interplay with Alzheimer’s.

Long story short, aging is your brain’s worst enemy. The same applies to all organs of our body, but the brain suffers the most. Both neurotransmitters and neurons are taking the blow too. As a result, the neuron communication is affected. Now, this may seem like the rocket science to you, but it’s enough to say, serotonin and dopamine are the most important neurotransmitters. Without these components, you can forget about good mood. Serotonin and dopamine levels drop at a rate of approximately 10% for every decade you add to your age.
The human drive to be smarter is a familiar theme on the big screen. In 2011, Oscar-nominated actor Bradley Cooper played struggling writer Eddie Morra in the sci-fi thriller Limitless. In the film, Morra acquires a (fictitious) nootropic NZT-48 that allows him to access 100 percent of his mind. Although he finds himself in lots of trouble, his use of the nootropic transforms him from a desperate writer to a multimillionaire who ultimately runs for the U.S. Senate. The film is a testament to a dream deeply entrenched in the American psyche – that an everyman can become superhuman and lead an extraordinary life.
But Baldino may have been overly modest. In 2002, researchers at Cambridge University gave 60 healthy young male volunteers a battery of standard cognitive tests. One group received modafinil, the other a placebo. The modafinil group performed better on several tasks, such as the "digit span" test, in which subjects are asked to repeat increasingly longer strings of numbers forwards, then backwards. They also did better in recognising repeated visual patterns and at a spatial-planning challenge known as the Tower of London task. (It's not nearly as fun as it sounds.) Writing in the journal Psychopharmacology, the study's authors said the results suggested that "modafinil offers significant potential as a cognitive enhancer".

So, I have started a randomized experiment; should take 2 months, given the size of the correlation. If that turns out to be successful too, I’ll have to look into methods of blinding - for example, some sort of electronic doohickey which turns on randomly half the time and which records whether it’s on somewhere one can’t see. (Then for the experiment, one hooks up the LED, turns the doohickey on, and applies directly to forehead, checking the next morning to see whether it was really on or off).
The research literature, while copious, is messy and varied: methodologies and devices vary substantially, sample sizes are tiny, the study designs vary from paper to paper, metrics are sometimes comically limited (one study measured speed of finishing a RAPM IQ test but not scores), blinding is rare and unclear how successful, etc. Relevant papers include Chung et al 2012, Rojas & Gonzalez-Lima 2013, & Gonzalez-Lima & Barrett 2014. Another Longecity user ran a self-experiment, with some design advice from me, where he performed a few cognitive tests over several periods of LLLT usage (the blocks turned out to be ABBA), using his father and towels to try to blind himself as to condition. I analyzed his data, and his scores did seem to improve, but his scores improved so much in the last part of the self-experiment I found myself dubious as to what was going on - possibly a failure of randomness given too few blocks and an temporal exogenous factor in the last quarter which was responsible for the improvement.
Took pill around 6 PM; I had a very long drive to and from an airport ahead of me, ideal for Adderall. In case it was Adderall, I chewed up the pill - by making it absorb faster, more of the effect would be there when I needed it, during driving, and not lingering in my system past midnight. Was it? I didn’t notice any change in my pulse, I yawned several times on the way back, my conversation was not more voluminous than usual. I did stay up later than usual, but that’s fully explained by walking to get ice cream. All in all, my best guess was that the pill was placebo, and I feel fairly confident but not hugely confident that it was placebo. I’d give it ~70%. And checking the next morning… I was right! Finally.
The ‘Brain-Gut Axis’ is a term used to describe the two-way communication system between our digestive tract and the brain. A growing body of research into this axis demonstrates how much influence the gut can have over the brain and vice versa (1). When we speak about reactions to foods, we most commonly understand them as immediate and often dangerous allergic responses, such as the constriction of the throat and trouble breathing, or dizziness and fainting. It is usually easy to pinpoint the food that causes these reactions because of the immediate immune system response, caused by a type of immune cell known as IgE antibodies. In contrast to this, food intolerances are mediated by IgG antibodies and these reactions can take up to 48 hours to have an effect. Symptoms related to IgG reactions can often be manifested as chronic issues like joint ache, IBS and depression or anxiety, which are often overlooked and not associated with what we eat.

According to the US Food and Drug Administration, "Piracetam is not a vitamin, mineral, amino acid, herb or other botanical, or dietary substance for use by man to supplement the diet by increasing the total dietary intake. Further, piracetam is not a concentrate, metabolite, constituent, extract or combination of any such dietary ingredient. [...] Accordingly, these products are drugs, under section 201(g)(1)(C) of the Act, 21 U.S.C. § 321(g)(1)(C), because they are not foods and they are intended to affect the structure or any function of the body. Moreover, these products are new drugs as defined by section 201(p) of the Act, 21 U.S.C. § 321(p), because they are not generally recognized as safe and effective for use under the conditions prescribed, recommended, or suggested in their labeling."[33]