Illicitly-manufactured fentanyls and synthetic opioids were initially introduced into east coast and midwest heroin supplies because these substances were viewed as an attractive cutting agent. Their increased sedative potency can be perceived as strengthening a batch of heroin and it mixed well into the characteristic “china white” heroin available in these regions.
Due to prohibition, there is more incentive for producers and distributors to minimize costs and maximize profits, while avoiding law enforcement detection. This is referred to as The Iron Law of Prohibition and has been used to explain why illicitly-manufactured fentanyls entered the underground opioid supply.
Sellers in the illicit market are constantly weighing costs and profit against potency. When cutting agents like illicitly-manufactured fentanyls and other synthetic opioids are added, this increases the quantity that can be sold. As long as a particular batch produces noticeable effects, demand will remain.
Illicitly-manufactured fentanyls and synthetic opioids have been found in counterfeit pressed pills sold as prescription opioids or benzodiazepines, and in trace amounts in batches of other drug supplies. It is still unclear whether their presence in non-opioid drug supplies is intentional or a result of unintentional cross-contamination from shared preparation surfaces or equipment.