I may be misunderstanding what you’re asking, so if I am, pls disregard.
Why would this be wrong, not true? Not all prescriptions act or feel the same in everyone. From side effects to efficacy, it can be different.
Amlodipine is for blood pressure, pretty standard Rx, very good to most folks. It causes me gingival hyperplasia *and* didn’t lower my bp. It’s pure, it’s tested, it works well for most—but not for me.
That’s every everything. Why does that seem strange to you, that a med that works for one may not work for another?