Among the many reasons I quit using recreational chemicals is that it's virtually impossible to be sure of the dosage. I mean, if you can't trust your local neighborhood drug dealer, who can you trust? Sure, he looks a bit shady, but that's just a matter of him being in costume for a role, yes?
Even now that some recreationals are being decriminalized, the dosage of active ingredients is still something of a crap shoot. Now, with booze, you can be pretty sure of the dosage. And if you overindulge, that's your own damned fault.