It is clear that you have already settled this discussion. The unfortunate byproduct of your being right however dictates the existence of a more or less equally powerful force that refuses to accept your victory. While the strength of evolution bestows to you the objective truth of your reason, which in a perfect world would facilitate fairness and uniformity, nature buries a beast unleashed by superiority desperate for something pathetic to sniff down at. You have not foiled yourself!
If your product produces inconvenient side-effects, produce a study that suggests a nocebo effect and keep pushing that product. By no means consider pathology specific susceptibility or try to reproduce the same nocebo effect in people who are in no apparent need of your condition curing chemical. Everybody knows that a shitty diet makes people feel shitty because they know it's a shitty diet. This was proved over the course of a year, when 60 shitty feeling consumers who had come of age on a shit-rich diet were given shells with shit and shells without shit, and even intermittently bags without any shells at all, during which they selected their shitty index from 1-100 from the convenience of their couches. Most of the time they indicated they'd felt like shit with little variance in just how shitty. Shit wins!
Snort the same lines of logic until nobody's listening.