To my understanding nootropics are cognitive enhancers that have minimal side effects, works on healthy individuals, where it benefits outweigh it's associated cost. Commonly and widely used nootropics are usually pharmaceutical agents that were used for other purposes than enhancing cognition, such as treating narcolepsy, ADHD, Parkinson's disease. The real version of the super cognitive enhancing drug in the movie "limitless" was inspired by the drug Modafinil, where it's no secret that getting hands on this drug can create an unfair advantage at school. Imagine this, you are close to an exam and you haven't read the textbook for the entire semester, Modaphinil might be able to get you up 24 hours straight and give you enough time to cram before taking the exam, and stay focus on the exam. I have tried Modafinil, it can work on enhancing wakefulness and attention, but felt more like other stimulants, with a prolonged but milder effects.
Image source (https://www.sportsgossip.com/the-best-adrafinil-containing-nootropic-stacks/)
Other commonly used drugs, like Modafinil, are mostly stimulants, such as methylphenidate, amphetamine, caffeine, nicotine etc... I wouldn't go into details (to be honest, to avoid exhaustive citation lists and making this post overly complicated) but as a general rule of thumb, at a small to moderate dosage, all stimulants would work. This is like how our bodies work, stimulants enables us to be more focused and on task. Not limited to stimulants, many drugs may benefit cognitive function, if used in very small dosages, typically a dosage that is 1/100th of a therapeutical dosage. e.g., marijuana, LSD. Unfortunately, a lot of the agents I have listed are probably not legal at most countries, and I would not recommend you to get them off the street, where you have no control over of what you are getting. Also, micro-dosing can be a dangerous route to pursue, as you might be prone to addiction and eventually lose control.
Luckily, some nootropics are natural products and you do not need a prescription for those, which may be safer to use and has less serious side effects. I'd like to share a few options.
Coffee and tea. Coffee and tea are widely available and routinely self-administered all over the world. The main active ingredient is of course caffeine. Caffeine is a stimulant and will help promote awareness, alertness and may even permanently increase your IQ (don't take my word for it, I heard of it but did not dig for citation). This is not without a cost of increasing the risk of cardiovascular diseases. What seems to be interesting is there are people promoting taking coffee and tea with fat. e.g., butter. Which supposed limit its negative effects and make the positive effects last longer. If you are interested you can google about bullet proof coffee and milk tea. I personally haven't tried those and don't know if it's legit. Note that tea also contains L-Theanine, which may work synergetically with caffeine. I have tried this supplement for a month, but really, nothing noticeable. You might be better off just drink some good tea.
Image source: (https://www.msn.com/en-ca/health/nutrition/are-coffee-and-tea-actually-dehydrating/ar-AAEd65V)
Nicotine. Nicotine comes from the night shade family of plants. Nicotine truly works, but be careful, smoking is not good for your lungs (cancer alert!). Also everything in moderation, or micro-dose. You really need to find the window that there's a balance of benefits and risks for yourself. I don't smoke, but I have tried a cigar in Cuba and enjoyed the feeling. It felt like my head is getting cooled and blown by a breeze. Perhaps skin patch or nicotine gum that were designed for people to quit smoking could be a route to choose.
Heishman, S. J., Kleykamp, B. A., & Singleton, E. G. (2010). Meta-analysis of the acute effects of nicotine and smoking on human performance. Psychopharmacology, 210(4), 453-469.
Image source: (http://pipesmagazine.com/blog/tobacco-policies-legislation/pipe-smokers-should-be-concerned-about-new-cigarette-laws/)
Some other natural supplements that may have an effect. e.g., Bacopa monnieri supposed to enhance memory and cognitive processing speed (I have ordered and will have a try). Ginkgo biloba, I have tried it a long time ago, will make your nose bleed... there's a rush sensation in your head but I think there's limited evidence on it really works on enhancing cognition. Panax Ginseng / Asian/ Chinese Ginseng supposedly will help on cognition, but not enough evidence is out yet. I personally tried those recently, it definitely helps with fighting fatigue (I played badminton last Friday, while on Ginseng, I felt much more energetic and less fatigue than previous Fridays ), a side effect from that might help you to perform better on mental work.
Ginkgo biloba
Image source: (https://www.123rf.com/photo_81432617_ginkgo-biloba-isolated-on-a-white-background-as-a-symbol-for-traditional-medicine-representing-natur.html)
Ginseng
Image source: (https://www.magicgardenseeds.com/The-Good-To-Know/Ginseng-(Panax-ginseng)-A.PAN01-)
Bacopa monnieri
Image source: (https://www.aquasabi.com/Bacopa-monnieri-Compact-pot)
Alright, I hope you have learnt something through this post. My recommendations, try to do your own research and try everything (if you decide to do so) in moderation.
Sorry to CN readers. I'd like to make a post in Chinese as well at a later time, which I will write to the CN community.
CN社区的小伙伴们，中文以后有时间我会另外发帖。敬请关注。🙏
