Is catnip safe for kittens? There is no evidence to suggest that catnip is in anyway harmful to the brain of cats, either kittens or adults. I take that conclusion from books that I have and from the internet.

The respected book ‘Cat Owner’s Veterinary Handbook‘ says on page 222 (3rd edition) that ‘Young kittens and about one-quarter of all adults cats are unaffected…’ By implication the respected veterinarians who wrote the book accept that kittens can enjoy sniffing and chewing on catnip.
Dr Bradshaw in Cat Sense writes that ‘A single gene governs whether or not the cat responds [to catnip], and in many cats, perhaps as many as one in three, both copies of this gene are defective, with no apparent effect on behaviour or general health‘. The author makes no references to catnip being harmful in anyway and does not mention the need to protect kittens.
However, I am obliged to be brave and speculate on my personal answer. In my view, not enough is known about catnip and its affect on the cat’s brain to be able to say with complete certainty that it is alright for kittens to ‘use’ the drug. In fact we don’t understand at a detailed brain chemistry level how the ‘drug’ works. And of course we can’t interview a cat to check her general mental health.
How do we know if catnip affects mental health? My personal theory is that we should not interfere with our brain chemistry using chemicals and this should or could extend to our cats. However, I have let my cat sniff catnip because when you buy scratching boards and posts you use catnip to encourage your cat to use the board. And advocates of catnip will say it provides enjoyment and that is a benefit to e.g. a bored indoor cat.
My assessment is based on how humans should protect children from the potentially harmful effects of drugs. But this is probably an erroneous way to proceed.
The conclusion, really, is that catnip is safe for kittens as far as we know. Catnip can affect all cats both wild and domestic no matter their size.
Monty is a mean drunk. No other cats here, but I know better than to touch him while he is all nipped up.
Recent piece in The Guardian showing images of human brains on LSD . Worth a read, if only for the descriptions of how it is thought the chemical works to alter perception. It is not nearly as shocking as one might expect. Certainly catnip is nowhere as dramatic in effect as LSD.
Psychedelic experiences can be beautiful, restorative and transformative to individuals. A lot depends on the state of mind, the company and the motivation to take a trip.
Cats seek out a buzz from a variety of plants, they tend to be self limiting in how much the consume, from my observations.
If only humans had a similar degree of self restraint!
Yes, you make a good point about aggression. Cat Owner’s Veterinary Handbook says: “Catnip may increase the sexual aggressiveness of males”.
Thanks Jane. If catnip affects the brain in a similar but milder way than LSD I’d be inclined to avoid it but that’s just me. At the moment I let Gabriel use catnip.
I have read that the genes (if they have them) for getting that nip buzz don’t turn on/get active until the ‘kitten’ is about 3 months old. Technically they are more adolescent at that age than kitten. It could be that stages of brain development play a part too.
Nepetalactone affects the brain in cats in a similar, but milder way that LSD affects in humans.
Oh wow, I’d like to see a big cat get all goofy on “the weed”, as it were. I don’t know of other people’s experience, but mine has been that when more than one cat is getting high on it, even separately (a couple feet away), they can get riled at each other. I mean, instantly hostile. I’ve done this a number of times to be sure, and I say don’t do it. Let them partake alone without any other cats in sight. No need to ruin a good thing. We don’t know why they like it either, but for the cats that it does affect, it can make them go goofy or super Ninja, the latter being a major buzz-kill for everyone. It is a great behavior enhancer to encourage them in some way, but it can also create a nasty fight if they get enhanced together. I’m surprised I haven’t read about it somewhere.