While most cats respond to catnip, there are some cats that do not. In fact, it’s estimated that around 30% of cats do not have a reaction to catnip. Here are some signs that your cat may not respond to catnip:

1. Lack of interest: If your cat does not show any interest in catnip, even after smelling or ingesting it, they may not be sensitive to its effects.
2. No visible response: Cats that are sensitive to catnip will often exhibit behaviors such as rolling, rubbing, licking, and purring. If your cat does not show any of these behaviors after being exposed to catnip, they may not be affected by it.
3. Aversion: Some cats may actually be averse to the smell of catnip, and may avoid it altogether.

If your cat does not respond to catnip, there are several alternative options that you can try:

1. Silver vine: As mentioned earlier, silver vine is a plant that grows in the mountainous regions of Asia, and contains compounds that can affect cats. Some cats may respond more strongly to silver vine than catnip.
2. Honeysuckle: Honeysuckle is a plant that is native to Asia and North America. The wood of the plant contains a compound called honeysuckle lactone, which can have a similar effect on cats as catnip.
3. Cat toys: There are many different types of cat toys available that do not contain catnip, such as toys filled with valerian root, silver vine, or honeysuckle.
4. Playtime and interaction: Even if your cat is not sensitive to catnip or other plants, they can still enjoy playtime and interaction with their owner. Interactive toys and games, such as laser pointers and feather wands, can provide mental and physical stimulation for your cat.

It’s important to note that while some cats may not respond to catnip or other plants, it does not mean that they are not able to experience pleasure or enjoyment. Every cat is different, and there are many different ways to provide mental and physical stimulation for your furry friend. If you have concerns about your cat’s behavior or responsiveness, it’s always a good idea to consult with a veterinarian or animal behaviorist for personalized advice.