From the place we shouldn't rely on totally Dr Google, but it should give you an idea, sometimes it is the binding materials et cetera that don't agree with us
Copy and paste:..............
Most people will never notice a difference. “According to the FDA, generic drugs do not need to contain the same inactive ingredients as the brand name product. Inactive ingredients are those that have nothing to do with the therapeutic action of the drug; binding materials, dyes, preservatives, and flavoring agents.Feb 22, 2015