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. 7 Oh Mitragynine Vape Our team has removed 17,311 packages of isolated and or concentrated 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. Parents: Have You Heard of 7 OH? A new substance called 7 OH ( 7 Hydroxymitragynine) is starting to appear in gas stations, vape shops, and online stores, and many people don't realize the risks.