It is important that this type of approach is discussed with a qualified health professional, such as a registered nutritional therapist, to ensure it is an appropriate strategy for you, as well as to help you avoid missing out on vital nutrients, whilst eliminating certain foods. They can also provide advice on improving your longer term health, which over time may allow for foods to be reintroduced without negative symptoms occurring.
My first dose on 1 March 2017, at the recommended 0.5ml/1.5mg was miserable, as I felt like I had the flu and had to nap for several hours before I felt well again, requiring 6h to return to normal; after waiting a month, I tried again, but after a week of daily dosing in May, I noticed no benefits; I tried increasing to 3x1.5mg but this immediately caused another afternoon crash/nap on 18 May. So I scrapped my cytisine. Oh well.
I’m wary of others, though. The trouble with using a blanket term like “nootropics” is that you lump all kinds of substances in together. Technically, you could argue that caffeine and cocaine are both nootropics, but they’re hardly equal. With so many ways to enhance your brain function, many of which have significant risks, it’s most valuable to look at nootropics on a case-by-case basis. Here’s a list of 13 nootropics, along with my thoughts on each.
See Melatonin for information on effects & cost; I regularly use melatonin to sleep (more to induce sleep than prolong or deepen it), and investigating with my Zeo, it does seem to improve & shorten my sleep. Some research suggests that higher doses are not necessarily better and may be overkill, so each time I’ve run out, I’ve been steadily decreasing the dose from 3mg to 1.5mg to 1mg, without apparently compromising the usefulness.
I eventually met Seltzer in an underground food court not far from the Pentagon. He's slim, with a shaved head, and he spoke precisely, rarely stumbling over his words. I asked him if he had any ethical worries about smart drugs. After a pause, he said that he might have a concern if somebody popped a neuroenhancer before taking a licensing exam that certified him as, say, a brain surgeon, and then stopped using the drug. Other than that he couldn't see a problem. He said that he was a firm believer in the idea that "we should have a fair degree of liberty to do with our bodies and our minds as we see fit, so long as it doesn't impinge on the basic rights, liberty and safety of others". He argued: "Why would you want an upward limit on the intellectual capabilities of a human being? And, if you have a very nationalist viewpoint, why wouldn't you want our country to have the advantage over other countries, particularly in what some people call a knowledge-based economy?" He went on: "Think about the complexity of the intellectual tasks that people need to accomplish today. Just trying to understand what Congress is doing is not a simple thing! The complexity of understanding the gamut of scientific and technical and social issues is difficult. If we had a tool that enabled more people to understand the world at a greater level of sophistication, how can we prejudice ourselves against the notion simply because we don't like athletes to do it? To me it doesn't seem like the same question. And it deserves its own debate."

If you are a slow caffeine metabolizer and consume too much caffeine, you run the risk of mild to severe complications, such as cardiovascular disease. There’s also the sleep disruption problem of having too much caffeine left in your bloodstream late in the day as a result of a longer caffeine half-life, a problem not faced by fast caffeine metabolizers (it’s so unfair if you love your cup of joe, right?). In addition, fast caffeine metabolizers actually run a reduced risk of cardiovascular complications if they consume at least one cup of coffee per day. While anyone can be a slow caffeine metabolizer, there are certain ethnic backgrounds that are indeed associated with slower and faster caffeine metabolisms. For example, it’s known that people with Asian and African ethnic backgrounds generally have slower rates of caffeine metabolism. To find out if you’re a fast or slow caffeine metabolizer, you can have a relatively inexpensive salivary genetic test performed by a company like 23andme and then use the online dashboard to jump straight to your CYP1A2 gene. When you’re there, you type into the search bar “rs762551”. If your rs762551 SNP variant is AA, then you’re a fast caffeine metabolizer, but if your variant is AC or CC, you’re a slow caffeine metabolizer. Fortunately, many genetic testing companies will now simply report directly on your results whether you’re a slow or fast metabolizer, without you needing to go through the SNP searching trouble.

-Water [is also important]. Over 80% of the brain’s content is water. Every chemical reaction that takes place in the brain needs water, especially energy production. The brain is so sensitive to dehydration that even a minimal loss of water can cause symptoms like brain fog, fatigue, dizziness, confusion and, more importantly, brain shrinkage. The longevity and well-being of your brain are critically dependent upon consuming hard water. This refers to plain water that is high in minerals and natural electrolytes. Most people don’t realize that the water they’re drinking is not actually “water”.
Since my experiment had a number of flaws (non-blind, varying doses at varying times of day), I wound up doing a second better experiment using blind standardized smaller doses in the morning. The negative effect was much smaller, but there was still no mood/productivity benefit. Having used up my first batch of potassium citrate in these 2 experiments, I will not be ordering again since it clearly doesn’t work for me.

There’s been a lot of talk about the ketogenic diet recently—proponents say that minimizing the carbohydrates you eat and ingesting lots of fat can train your body to burn fat more effectively. It’s meant to help you both lose weight and keep your energy levels constant. The diet was first studied and used in patients with epilepsy, who suffered fewer seizures when their bodies were in a state of ketosis. Because seizures originate in the brain, this discovery showed researchers that a ketogenic diet can definitely affect the way the brain works. Brain hackers naturally started experimenting with diets to enhance their cognitive abilities, and now a company called HVMN even sells ketone esters in a bottle; to achieve these compounds naturally, you’d have to avoid bread and cake. Here are 6 ways exercise makes your brain better.

Modafinil is not addictive but there may be chances of drug abuse and memory impairment.  This can manifest in people who consume it to stay up for way too long, as a result, this would probably make them sick. Long-term use of Modafinil may reduce plasticity and can have an adverse effect on the memory of some individuals. Hence it is sold only on prescription by a qualified physician.
Panax ginseng – A review by the Cochrane Collaboration concluded that "there is a lack of convincing evidence to show a cognitive enhancing effect of Panax ginseng in healthy participants and no high quality evidence about its efficacy in patients with dementia."[36] According to the National Center for Complementary and Integrative Health, "[a]lthough Asian ginseng has been widely studied for a variety of uses, research results to date do not conclusively support health claims associated with the herb."[37]