Not sure if this has been posted before (Abstract of study) User Elgar2689, in the Kratom subreddit, 01 Jun 2016
The main active alkaloid substances in kratom, mitragynine and 7-hydroxymitragynine, present with a range of CNS stimulant and depressant effects mediated primarily through monoaminergic and opioid receptors. Also multiple confirmed deaths. User Motherlicka, in the DrugNerds subreddit, 06 Nov 2015