Yes, catnip can be used to calm down an overly hyperactive cat. However, it is important to understand the effects of catnip on cats and how to use it properly.

Catnip is a herb from the mint family that contains a compound called nepetalactone, which can affect a cat’s behavior. When a cat smells or ingests catnip, it can cause a range of reactions, including hyperactivity, euphoria, and relaxation. About 50-70% of cats are affected by catnip, and the effects usually last for around 10-15 minutes.

If you have an overly hyperactive cat, offering them some catnip can help to calm them down. The relaxation effects of catnip can help to reduce a cat’s anxiety, stress, and hyperactivity. However, it is important to use catnip in moderation, as too much can have the opposite effect and make a cat more hyperactive.

You can offer your cat catnip in several ways, including:

1. Dried Catnip: You can purchase dried catnip from a pet store or online. Sprinkle a small amount of catnip onto a toy or scratching post to encourage your cat to play and relax.
2. Catnip Spray: You can purchase catnip spray, which is a liquid form of catnip. Spray it onto your cat’s bedding or toys to encourage relaxation.
3. Fresh Catnip: If you have access to fresh catnip, you can offer it to your cat by placing it in a toy or rubbing it onto a scratching post.

It is important to note that not all cats react to catnip in the same way. Some cats may not be affected by catnip at all, while others may become extremely hyperactive. Additionally, it is not recommended to give catnip to kittens under six months of age, as their nervous systems are not yet fully developed.

In conclusion, catnip can be a helpful tool to calm down an overly hyperactive cat. However, it is important to use it in moderation and to understand your cat’s individual reaction to catnip. If you have any concerns about your cat’s behavior, it is always best to consult with your veterinarian.