I would say it is not but I haven't done any research....
Because kratom has given so many people their lives back and there are governments who are working to have it banned, if it were me, I would not want to add to the misconceptions that people have about it or give any government more reasons that support their case to ban it, by attempting to overdose with it.
There have been OD deaths where the person passed with lethal amounts of street drugs on their tox screens in conjunction with 'some' Kratom, and their heartbroken but misinformed families have gone to the media to call for Kratom to be banned when it was not to blame for their loved one passing.