Earlier quoted context omitted.
Xylazine and fentanyl are already legally distributed in the US. I believe Xylazine is still unscheduled. https://www.dechra-us.com/our-products/us/equine/horse/presc...
Those are the adulterants, not the drugs being adulterated such as heroin, meth, and MDMA. For the most part, no customer wants fentanyl. The dealers like it because it's a cheap booster for cutting the drugs that their customers actually do want to buy. It just has this unfortunate side effect of making small overdoses lethal. That's why "ending the fentanyl crisis" is a curious goal. We had a perfectly good War on…
I'm not sure I believe that making heroin legal and available for "recreational" use would solve the problem. People who propose it usually say that it's working in another country (such as Portugal), but then you look at that country and it's not really legal or available, it's just that they do not jail people for personal use anymore. I can agree with that, but it doesn't solve the trafficking problem. The only way to get rid of trafficking is to either allow people to easily buy it legally without onerous taxation, or to reduce demand to zero. If you do the former, you will still be stuck with lots of addicts, the associated crime and suffering, and probably many overdoses. Most likely, the number of addicts will increase, as they did with OxyContin, Actiq, etc. Worth mentioning that Actiq is fentanyl and it was in demand.
Reducing demand is a multifaceted problem with complicated solutions, many of which are politically unpopular.
Interestingly, some drugs can simply be taken off the market and the demand plummets. Quaalude is one example. Nobody stepped in to make an illicit version and the users probably just stopped using or switched to benzodiazepines and then hopefully stopped those. Unfortunately, it seems like we have a persistent demand for opioids.