Estimating the average dosage of heroin [2] (regardless of whether it's snorted, smoked, or injected) can be quite difficult, if not impossible. Why, you ask? Heroin, an opioid synthesized from morphine, is an illicit drug. As such, there aren?t any regulations or recommendations on dosage or on any substances with which the drug may be cut (heroin is often mixed with other substances such as s...