I’m not sure if that was clear but what I mean is that I find that generic medications (i.e. for allergy and colds) work better for me than something like Sudafed or Benadryl. The store in question is CVS, but there was even an allergy medicine I used to get from Costco that was the store brand (Kirkland Signatures, was it?) that worked better for me than other name-brand drugs.
Is there any reason why I should find this to be the case?
Generics, sugar pills, tic tacs. Really any placebo should do the trick.
In reality, generics are not necessarily the same as name brand medication. They may have identical ingredients but there might be lower quality controls and whatnot with generics.
Generics will often have a different coating than name-brands. Sometimes folks are forced to purchase the name-brands because they’re allergic to or get too many side effects from the generics. Also a difference in coating means a difference in dissolving. Generics might dissolve better, quicker or slower in your system.
OK I don’t seem to have a cite for my above info but I swear I’ve heard it and in fact I’ve read it on this board 
Here’s a page about Generic vs. Brand-name drugs with some good info as to why they’re cheaper.