The cuts in heroin will vary from location to location, but they are existent in some amount in every bag of heroin. Not all drug dealers are that health conscious, of course if all smack and coke were cut with strychnine then the addicts would drop dead and dealers fucking themselves over. Rather it is cut differently everywhere. Some people may just cut with some talc, flour or powdered sugar while others use more toxic substances such as synthetic opioids like fentanyl. The dealer you got it froms supplier probably wouldn't be able to tell you what else besides heroin is in the bag.