Synthetic drugs might also be called designer drugs or lab drugs. Because they are made in labs, chemists can try to adjust them to have specific properties that they want.  Despite the jargon used, it needs to be emphasized that no chemist, especially underground chemists selling drugs that are meant to skirt regulations, can perfectly synthesize a drug that has only “good” effects with no health downsides. Chemistry and medicine simply haven’t advanced far enough for us to predict exactly what a drug will do without substantial research, which the majority of these drugs don’t get.