Nootropics are pharmaceutical compounds that are used to enhance cognitive function. They were discovered several years ago. There is comprehensive research behind many nootropics showing they enhance many key aspects of cognitive learning. The spectrum of nootropics is very broad so here we will only cover those with the most research lurking behind them and those that have shown significant improvements in cognitive ability.
As well as improvements in healthy individuals, there is comprehensive research with nootropics used for relieving indications of brain diseases such as Alzheimer's, Parkinson's and Multiple Sclerosis (MS). Nootropics help protect the brain and the central nervous system from damage. Have a look at http://www.purenootropic.com/nootropics-review/nootropic-stacks/, to know more about nootropics stacks.
Other than this, there is several other substances that can also affect the central nervous system but is not classed as nootropics. These substances include caffeine, nicotine, Cannabis or Ritalin. True nootropics meet a set of criteria that are seen more as nutrients than as drugs. This include:
1) Aniracetam – A stimulant and cognitive enhancer that acts in almost 20 minutes.
2) L-Theanine – Naturally found in Green Tea, this reduces anxiety and improves learning
3) Piracetam – One of the most extensively studied nootropics for cognitive enhancement
4) Pramiracetam – A more potent variation of Piracetam enhancing memory and learning capacity.
All of the above have no side effects or dangers to a human body.