I'm sorry but kratom isn't an opioid. It acts like a mild selective serotonin reuptake inhibiter, like a dopamine releasing agent as well as a D1 dopamine agonist, and as a partial agonist of the mu opioid receptor ; which is why it's not an opioid ! Opioid generally acts on delta and kappa opioid receptors too and fully agonize those receptors. Which is why you can't OD from kratom and why it's not an opioid. Hope it helps :)