Theanine can also be combined with caffeine as both of them work in synergy to increase memory, reaction time, mental endurance, and memory. The best part about Theanine is that it free of side effects and is easily available in the form of capsules.  A natural option would be to use a good green tea brand which constitutes of tea grown in the shade, because then Theanine would be abundantly present in it.
Googling, you sometimes see correlational studies like Intake of Flavonoid-Rich Wine, Tea, and Chocolate by Elderly Men and Women Is Associated with Better Cognitive Test Performance; in this one, the correlated performance increase from eating chocolate was generally fairly modest (say, <10%), and the maximum effects were at 10g/day of what was probably milk chocolate, which generally has 10-40% chocolate liquor in it, suggesting any experiment use 1-4g. More interesting is the blind RCT experiment Consumption of cocoa flavanols results in acute improvements in mood and cognitive performance during sustained mental effort11, which found improvements at ~1g; the most dramatic improvement of the 4 tasks (on the Threes correct) saw a difference of 2 to 6 at the end of the hour of testing, while several of the other tests converged by the end or saw the controls winning (Sevens correct). Crews et al 2008 found no cognitive benefit, and an fMRI experiment found the change in brain oxygen levels it wanted but no improvement to reaction times.

Whole grains, which you digest slowly, provide fuel for your brain. (Although your brain accounts for only 3 percent of your total body weight, it uses 20 percent of energy.) Rich sources include brown rice, whole wheat bread, quinoa, bran flakes, oats, and barley. According to Science Daily, brain food containing whole grains can boost cardiovascular health, which in turn enhances the flow of blood to the brain. They contain more intact nutrients than processed white flour, including vitamin E, antioxidants, and fiber. When these work together to increase blood flow, the integrity of brain cells is better preserved. To keep your brain sharp, go beyond your diet and incorporate these healthy brain-boosting habits into your routine.
Attention Deficit and Hyperactivity Disorder (ADHD) is a condition that relates to a collection of behavioural symptoms such as hyperactivity, impulsiveness and inattentiveness. It is most commonly diagnosed in childhood between the ages of 6 and 12 when disruptive behaviour begins to show, however, due to a growing awareness of the condition, it is also becoming common among adults. According to the thinktank Demos, the cost of undiagnosed ADHD in adults in the UK who are unable to work or hold down a full-time job are estimated to cost billions of pounds to the nation. They warn that too many may be going through life struggling, unable to access the support ot diagnosis they need, which means there could be a huge amount of wasted talent.
Essential fatty acids (EFAs) cannot be made by the body which means they must be obtained through diet. The most effective omega-3 fats occur naturally in oily fish in the form of EPA and DHA. Good plant sources include linseed (flaxseed), soya beans, pumpkin seeds, walnuts and their oils. These fats are important for healthy brain function, the heart, joints and our general wellbeing. What makes oily fish so good is that they contain the active form of these fats, EPA and DHA, in a ready-made form, which enables the body to use it easily. The main sources of oily fish include salmon, trout, mackerel, herring, sardines, pilchards and kippers. Low DHA levels have been linked to an increased risk of dementia, Alzheimer's disease and memory loss whilst having sufficient levels of both EPA and DHA is thought to help us manage stress and helps make the good mood brain chemical, serotonin. If you're vegetarian or vegan, you may wish to add seeds like linseed and chia to your diet, or consider a plant-based omega-3 supplement. If you are considering taking a supplement speak to your GP first.
One thing I did do was piggyback on my Noopept self-experiment: I blinded & randomized the Noopept for a real experiment, but simply made sure to vary the Magtein without worrying about blinding or randomizing it. (The powder is quite bulky.) The correlation the experiment turned in was a odds-ratio of 1.9; interesting and in the right direction (higher is better), but since the magnesium part wasn’t random or blind, not a causal result.
Alex remains enthusiastic about Adderall, but he also has a slightly jaundiced critique of it. "It only works as a cognitive enhancer insofar as you are dedicated to accomplishing the task at hand," he said. "The number of times I've taken Adderall late at night and decided that, rather than starting my paper, hey, I'll organise my entire music library! I've seen people obsessively cleaning their rooms on it." Alex thought that generally the drug helped him to bear down on his work, but it also tended to produce writing with a characteristic flaw. "Often I've looked back at papers I've written on Adderall, and they're verbose. They're labouring a point, trying to create this airtight argument. I'd produce two pages on something that could be said in a couple of sentences." Nevertheless, his Adderall-assisted papers usually earned him at least a B. They got the job done. As Alex put it: "Productivity is a good thing."
But before you go lock yourself in a dark, quiet room in order to prevent this overburden on your brain, you should know that there are scientifically researched compounds designed to amplify cognitive function and help your brain deal with this excess load, or simply get you through a period of sleep deprivation, increased creativity or work demands, the need to pull an all-nighter or an intense bout of work or study.

DAY B-1 1.5 mg B-2 1.7 mg Niacin 30 mg B-6 40 mg Folic Acid 400 mcg B-12 500 mcg Biotin 100 mcg Pantothenic Acid 10 mg Magnesium 100 mg Spirulina Algae Powder 5 mg Tongkat Ali Root 5 mg Panax ginseng 5 mg American Ginseng 5 mg Rhodiola rosea 5 mg Maca Root 5 mg L-Taurine 100 mg Acai Fruit 100 mg Caffeine Anhydrous 100 mg NIGHT Ginkgo biloba 50 mg Phosphatidylserine 125 mg N-Acetyl L-Carnitine HCl 50 mg St. John's Wort 250 mg L-Glutamine 50 mg Bacopa 100 mg Vinpocetine 2 mg Huperzine-A 10 mcg

Before you try nootropics, I suggest you start with the basics: get rid of the things in your diet and life that reduce cognitive performance first. That is easiest. Then, add in energizers like Brain Octane and clean up your diet. Then, go for the herbals and the natural nootropics. Use the pharmaceuticals selectively only after you’ve figured out your basics.

Research does not support that drugs like Ritalin help students do well in school. Studies show that prescription stimulants do not help to improve learning or thinking in those who do not actually have ADHD. Further, research reveals that students who abuse prescription stimulants have lower GPAs than students who do not abuse the drugs.[14] Although Ritalin improves concentration, this effect is largely misunderstood among non-prescribed users. These illicit users mistakenly believe that they can use a drug out of its prescribed context, thinking they can reap the benefits intended for legitimate users.

The main concern with pharmaceutical drugs is adverse effects, which also apply to nootropics with undefined effects. Long-term safety evidence is typically unavailable for nootropics.[13] Racetams — piracetam and other compounds that are structurally related to piracetam — have few serious adverse effects and low toxicity, but there is little evidence that they enhance cognition in people having no cognitive impairments.[19]