I bought these at the vets after checking to make sure amazon price was the same (it was)…i introduced a VERY active kitten to a household of two 4 year old cats. (mistake). the older cats were terrorized…chased around the house, hissing, carrying on, even after a slow two week introduction with kitten shut in another room. when i took the kitten to the vet they put a thundershirt on him, because he was climbing up my face….it instantly calmed him down. so i bought one for him (small) and one for the cat most hostile to him (large). the pros: they do calm the cats down…with no ill effects that i have found. they can still walk around and play, but it takes the “edge” off — and softens the hostility. cons: the wrap-around collars are uniformly too large, though they don’t seem to effect function, they do get in the way of other collars or harnesses, and just kind of hang in the way. they are also hot, so not practical for summer wear. ans it can be challenging to get them just the right tightness. you don’t want to squish them like a sausage, but it has to be somewhat tight to be effective. consequently, it gives longer haired cats a version of “hat hair” …they spend a lot of time grooming when they are taken off. but i have had them wear them all night just because that’s the time most of the fights happen — last night the hostile adult and the kitten both slept in the same bed with me, both purring, wearing their thndershirts. so it does work. these shirts are good for car travel, vet visits, introduction to a new animal, and other generally stress-inducing situations. one tip: un “zip” the velcro away from the cat. they don’t like it if you put the shirts on and then pull open the velcro, cause it makes that scary noise. my cats don’t resist putting the shirts on, and i am careful to praise them a lot when they put it on…

I work as a veterinary technician bought this product for use at my vet clinic. I have found that it works great for scared cats that want to run or the cats who just won’t hold still. They tend to just freeze and stay still which is great for blood draws and exams. The chest strap never seems to get tight enough but I have used it without the chest strap and it still works great. In general, the sizes run a little small. It is labeled for 9-13 lb cats. That is only if they are at their ideal weight. It will not fit a fat and round 11 lb cat. However, it does fit cats smaller than 9 lbs without any issue. I haven’t been able to use it on the really hostile cats because they won’t tolerate me putting it on. It is pretty easy to wrap an angry cat in a towel when their feet are also restrained. However, it is not easy to wrap something around their chest when all their claws are still ready and able to strike. Great for scared cats in flight mode but not for really hostile ones in fight mode.

Our 19# kitty, Laser, REALLY hates to fly, and we had resorted to giving him Valium. It made him less hysterical but he felt so whacked out he’d yowl much of the flight AND the entire first night after we’d arrive. So let’s just say that NO ONE liked that he traveled so poorly!

A friend recommended the Thundershirt, and we were reminded of it when we saw an ad in the airline’s in-flight shopping magazine. We ordered the large size, which seemed to be fine for our big guy. It’s pretty adjustable and we got it to fit pretty well, but Laser was so mellow in it he didn’t seem to care if it was or wasn’t on perfectly.

We first tried it for the road trip to the airport, and we had ZERO yowling. Then on the airplane, it was still great. I hadn’t doped him up but had the pills with us just in case. The Thundershirt took enough of the edge off for him that he wasn’t thrilled to be on a plane, stuffed in a small bag, but he was mellow and not freaking out. Yahoo! Good enough for me!

We seriously had gotten to the point where we were considering road tripping for 4 days instead of having to fly with him, especially as some flight attendants say that the FAA rules require that the animal’s carrier be kept under the seat ahead of you for the ENTIRE flight, not just for take off and landing. Our big scaredy cat is so much calmer if you can have the carrier on your lap, with your arm stuck in the carrier so he can rest his head on your arm. And this is a cat that doesn’t like to sit on laps! But while some flight attendants are OK with that, I’m sure too many people abuse it by taking their animals completely out of their carriers, so some are really strict. On one flight on a smaller, connecting plane, Laser got so scared while under the seat ahead of him, he ripped through his carrier and was trying to climb up into my lap. I had to take a cab on our layover and buy another carrier in a seriously sketchy neighborhood with my 6 year-old daughter. Fun stuff.

I’m so relieved to have found the Thundershirt. The pheromone sprays, Valium, Rescue Remedy, etc were never enough to make travel bearable. And unlike the Valium, when you’re at your destination, you just take off the Thundershirt and there are no residual side effects, wobbly walking or all-night yowling. He doesn’t love thunderstorms but he just hides under a bed and seems OK so we haven’t used it except for car and plane trips. But, man, the bipeds in our family were SO less stressed because our sweet kitty was less stressed. We are really thankful and can’t recommend it enough!