> about one-third of cats are not affected by catnip.[6][7][26][34] The behavior is hereditary.[35]

https://en.wikipedia.org/wiki/Catnip#Effect_on_felines

squares

Some cats respond to Valerian root instead.

Also, there's definitely some potency or freshness qualities of catnip.

I'd tried it with my cat and thought for years she didn't respond, but I ended up with a small sachet and she went bonkers, but I don't know what the difference was.

>Also, there's definitely some potency or freshness qualities of catnip.

My cats (7 of them) looooove the dried, store-bought catnip, but have very little interest in the fresh stuff out of my garden. Thought I might try drying some of the stuff from the garden as a kind of clinical test to see if the store bought stuff is somehow different from what I'm growing.

There may not have been any. There's some evidence that catnip response is not just context-sensitive in that the same cat a few days apart might respond differently, but also that catnip insensitivity might change over the span of a few years. Like most things about catnip, any reason for this is a mystery.

Try a different catnip. Some catnip we bought was fully ignored while other brands were basically slammed out of our hands on sight.

No clue why, maybe some outlets sell fakes or there are different kinds?

Some cats prefer fresh catnip over the dried stuff sold in stores