The products retail for just under $40, and are sold online and in retail stores like Bed, Bath and Beyond and many veterinary offices.
"I cannot guarantee they work because the research is not there to prove that they are effective," said Dr. Soraya Juarbe-Diaz a veterinarian who specializes in pet behavior treatment.
Juarbe-Diaz, who goes by Dr. JD, said the idea for an adjustable shirt for pets to wear came from a product that was used on autistic patients. Coats that sort of swaddled these autistic adults were shown to be very effective.
The idea to apply this technique to autistic people actually came from something that's been used on animals for decades.
"In large animal veterinary medicine, cattle goes into a shoot and we are able to turn the animal on its side and trim its hooves or examine it's underside, " said Dr. JD.
Pet owners like Mary Weinaug are optimistic that something like the thundershirt will help calm her dog Jude's fear of thunder and fireworks.
"He is so deathly afraid of fireworks one year he even ran away," said Weinaug.
She tried a Thundershirt on her 4-year-old Dalmatian and watched to see his reaction as her husband lit off a firework outside.
Instantly Jude ran and hid under Mary's feet and cowered for attention, the same reaction he would normally have to unpleasant noises.
Lindsay and Joe Guzman had a little better luck when testing the product on their American bulldog-mix, Harley.
"She's been the best dog, but she has anxiety to noises like the door slamming, turning the fan off, people walking by," said Lindsay.
When they put the shirt on Harley, she instantly calmed down despite a news crew and lots of commotion being present in the house.
The Guzmans said they put Harley in the shirt during a birthday party celebration they had at their home and they felt it helped out immensely.
A reporter at Channel 4's sister station in Orlando also tested the product on her pet. Lisa Bell's cat Kiwi is anxious around strangers and small children. Kiwi was hissing as the news photographer tried to get video of her. But when Bell put her in the Thundershirt, she appeared to calm down.
Dr. JD said not all pets would benefit from this type of product, but it is safe to try.
"The pro is, it's not going to have a side effect. And both of these products have a money back guarantee so I tell owners if you want to try it, I think it is OK for you to try it," she said.
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