Both of my cats really don't react to catnip. They will eat it, but that's about it.
I do have a photo from when I first got Ganymede (he was approximately 8 weeks old, I think) and all 4 cats in my house at the time were rolling around on my kitchen floor in catnip. That is the most reactive I have ever seen them, they haven't done it since.
Kind of disappointing because you see so many videos of cats just going nuts after being exposed to catnip! I wish mine were like that! They might not react to it anymore because I pretty much leave some out for them all the time, though.
I found the quality of the catnip makes a difference. My cat Geronimo from years ago loved to eat the organic catnip, and made him a little nuts once in awhile. I bought some cheap stuff and when I gave it to him he sniffed it then attempted to bury it like it was a pile of...... but he did that with other things he thought stunk like cat puke, food he didn't like etc.