Honestly, I don't find I notice much with modern medicine either, which is why I typically don't really use medication (or herbs for that matter)
Even things like coffee, which supposedly have quite a noticeable and consistent effect for people, don't really work the same way for me. If I drink coffee, I either notice nothing, or I get very sleepy. So then I kinda started to doubt if things have the effect that people say it has, and how to check better what effect it has on me specifically.
Once, a doctor also prescribed me these pills with passionflower extract to relax. And I found it so weird that one would have to pay quite a lot for pills that just contain some plant that can grow indefinitely in your garden. Either way it didn't matter because I didn't feel any effect, medication or herb.