There is considerable and compelling evidence from both the animal and human literature that the actions of the somatotrophic hormonal axis (growth hormone releasing hormone/growth hormone/insulin-like growth factor I) have significant and predictable effects on cognitive function (memory and reasoning ability). A preliminary study has recently shown that five months of growth hormone releasing hormone (GHRH) treatment improves cognitive function in healthy older men and women; there is also preliminary evidence that supports the likelihood of a similar effect in individuals diagnosed with MCI.