Actually, the substance used was pregnenolone carbonitrile (PCN), which is a direct derivative of pregnenolone (I think) and a precursor/parent to progesterone. So, pregnenolone should have similar effect but probably in higher doses, and progesterone could potentially also have such affect given how close it is structurally to PCN. Here is the study:
http://www.ncbi.nlm.nih.gov/pubmed/1203555
There was another study in rats that used actual pregnenolone and the human dose equivalent was 500mg-600mg per day.
http://www.ncbi.nlm.nih.gov/pubmed/1203555
There was another study in rats that used actual pregnenolone and the human dose equivalent was 500mg-600mg per day.
