The following is a collection of sources, on various substances, that have a substantial cognition-increasing reputation. This is by no means every substance that may do so. More will be added, and existing ones built upon, as time permits!

Research principles…

Information was found on scholar.google.com (google scholar) by typing such search terms in as, along with the substance in question, “cognition”, or “nootropic”. When possible, systematic reviews and meta-analyses are cited. Additionally, none of these sources are more than ten years old, and many have been peer-reviewed. Depending on volume of relevant studies discovered, results were scanned for several pages (three or more), after which keywords were changed.

I do cite sources that deal with subjects who aren’t entirely healthy to begin with. For instance, one about the ability of modafinil to normalize learning in methamphetamine users. Stimulants have a significant reputation for increasing various domains of cognition. As such, the study relates to healthy individuals, though indirectly.

On the other hand, such studies may not be valid. Pharmacological Enhancement of Memory and Executive Functioning in Laboratory Animals discusses how normal subjects might respond to a supplement or drug in a completely different manner than someone with a condition that affects their cognition. Also discussed are such potential issues as using animals to implicate claims regarding humans, and how increasing one cognitive domain, may decrease another.

It’s very important here to state that the best cognitive enhancers, in my opinion, are the fruits of nature:

  • Physically working, continuing to become stronger through regular exercise
  • Mentally working, routinely reading a complicated book, or perhaps habitually engaging others in intellectual conversation
  • Spiritually working, going out of your way to do good deeds (mitsvahs) for others, maybe cultivating daily meditation, or praying

There is no pill such as that in the movie Limitless.

Furthermore, all medicines can also be poisons. For instance, a typical dose of memantine is 5 mg. At 30 mg, it tends to impair cognition much more than it enhances it.

Here we have the outline…

  • Tobacco
    • Dip tobacco
    • Nicotine
    • Smoked tobacco
  • Fish oil
  • Ginko biloba
  • Caffeine
  • Classic stimulants
    • Amphetamine
    • Methylphenidate
    • Methamphetamine
  • Antidepressants
    • Overall
    • Bupropion
  • Modafinil/armodafinil/adrafinil
  • Racetams
  • Hydergine/ergot alkaloids
  • MAO-B inhibitors
    • Selegiline
    • Rasagiline
  • Memantine
  • Acetylchollinesterase inhibitors
  • Acetylcholline precursors

As we see in the image below, there are many more substances that may have nootorpic potential, than this section covers. One thing to keep in mind is, no psychotropic chemical is without its negatives. For instance, we see adderall as occupying the highest mean rating position. But this states nothing of its risk for producing severe side effects, including psychosis, agitation, addiction, and even neurotoxicity. And if you’re caught with even a few pills and don’t have a prescription, they could stick you with a felony, which stays on your legal record for life. Felons have an extremely difficult time securing good jobs.

We’re now moving on to the pill/pharmaceuticals. As a general rule, they are more risky, and pervasive, than natural products.

  • Classic stimulants

  • Antidepressants
    • Well-known is the idea that depression itself oftentimes dampens cognition
    • A recent systematic review of over 65 trials assessing the effects of a large portion of popular antidepressants when dosed once, findin gno positive, and one negative: greater fatigue
    • SSRIs and MAOIs used as monotherapy (one threapy) for alzheimer’s disease
    • A meta-analysis discovered that tricyclic antidepressants work better than SSRIs for those with parkinsons disease
    • Bupropion

  • Acetylcholine precursors
    • Citicoline
      • In a systematic review, involving 13 studies over 30 years
        • Improved recovery speed for patients with traumatic brain injury
        • Increases attention, executive function, and reparation of neurons in people who’ve recently had strokes
        • Effective for behavioral, emotional, and cognitive issues
        • Improves motor skills, attention, behavior, and perception in those with cerebrovascular disease
        • Promotes greater blood flow in vascular diseases
        • And in those with alzheimer’s, improved circulatory function and cognition

*Armodafinil and adrafinil are, essentially, modafinil. Armodafinil is one of the two very closely related chemicals that make up modafinil. Adrafinil is converted in modafinil by the body, after being ingested.*

Sources: google.scholar.com, studies cited by links (per usual), http://link.springer.com/article/10.1007/s00213-008-1395-1