In the United States you can sell non-controlled supplements. For example you used to be able to buy MDMA (street name ecstasy/molly) over the counter at health food stores in the 1980s before the government classified it. In my area there are all kinds of strange stimulants sold in gas stations, and something called kratom people seem to get mildly hooked on.

The drug dealers were ex-marines that received debilitating injuries fighting in Afghanistan, became addicted to pain pills when they came home, and because of their injuries were unable to work. So they were selling drugs. Then the analog act came around, which made a large amount of closely related drugs illegal. They were drug dealers, and should be in prison. Someone died from these weird compounds they were bringing in from China to try and skirt the Analog Act. But these guys in their head justified it because they were using the same compounds, and they felt they needed to subdue their pain. But these guys also didn't hide it. They had a lawyer that they ran things by. They bought cars from dealerships with their money, not trying to hide it in any way.

I don't think 'good faith' should apply to them. But also don't think 'good faith' should supersede the United States Constitution. If it applies to the prosecution side, it should apply to the defense. A judge shouldn't be able to waive away our Constitution just because it's inconvenient in a prosecution. In the US, even if something is determined unconstitutional and that determination means people should be released from prison, every single person impacted has to go to court and prove it applies to them. We should release people imprisoned unConstitutionally, but we don't, because again it's inconvenient to the legal system. There is even a time limit on those people to go to court, and if they don't in time (say because they don't know, because they aren't notified) then they are bared from bringing it up in a motion to the court.

Drugs are a hard one. I blew up my life over addiction. Many around me were to. Some were using drugs, some alcohol, some gambling, some risky sex. One interesting feature of American society is we used to give people a second chance. For old guys like me, many of the characters in westerns were criminals turned better as law men one town over. These guys would have been completely different if they were receiving adequate pain care and some sort of job opportunities when they came back from war. I think society needs that. But it also can't enable bad behavior. Interesting/complex times.

Sorry for my wall of text.