The supply of high potency opioids is expanding through products sold legally as herbal supplements in gas stations, vape shops, and convenience stores. The most prominent is 7 hydroxymitragynine, also known as 7 OH. Buy Stack'd 7 Hydroxymitragynine Disposable Vape Pen Blue Razz 2g 200mg KratomGala.com 7 Oh Mitragynine Vape PainCrusher Rx 7 Oh 2 Gram Disposable Vape Cloud Nine Shoppe 7 Doctors are warning about a substance they call gas station heroin that is available over the counter at vape stores across Arizona. The product is called 7 OH, a component derived from kratom.