NSI-189 is a relatively uncharacterized molecule, again. However, NSI-189 has been tested in a human study with the aim of measuring mood and cognitive abilities [1]. It was found that NSI-189 improved mood and cognition without adverse affects in a very small Phase I clinical study. While in the study 40 mg was tested once, twice or three times per day, the 40 mg dose once per day seemed to be sufficient for the effect. The mechanism of NSI-189 is yet unclear but in an rat brain stroke study it appeared that NSI-189 was able to attenuate post-stroke cell death mechanisms in one hand and to increase the cell neurite growth in the other hand, possibly by mechanism of increasing the release of  brain growth factors such as BDNF and SCF [2]. It has been suggested that a substance that is capable of stimulating brain stem cell growth in the hippocampus as well as improving the mood in the long term deserves further research indeed [3].

[1] https://www.ncbi.nlm.nih.gov/pubmed/26643541

[2] https://www.ncbi.nlm.nih.gov/pubmed/28181668

[3] https://www.ncbi.nlm.nih.gov/pubmed/28460574