It's my understanding that most of the nootropic drugs are temporary stimulating agents.
Some outcomes more anecdotally profound than others.
The really interesting stuff is the nerve growth factor in the nootropic, cerebrolysin. The Russians have been using it forever and there are some interesting fast time elapsed videos of axon/dendrite (??) formation with and without cerebrolysin. But these nerve cell samples were outside of the body - so I believe it's fairly difficult to keep nerve cells alive in culture.
So, the videos might not be legitimate.
*shrugs*
Many true nootropics are proven to reduce age related mental decline and/or positively effect various pathways involved in cognition (free feel to inquire for any research). The effects can be cumulative depending on the compound. Many people try group in stimulants or addictive drugs with nootropics, however this goes against the original definition of nootropics.
I do not consider Kratom a Nootropic. More a mood enhancing herb with several unique modes of actions.
Cerebrolysin is a peptide extracted from pig brain. While it is interesting there are a number of other nootropics more commonly available that have proven cognitive or other enhancing effects in healthy adults.
