Yes, little shirts really can help dogs! Of course, clothing can be good for people, too.
At School For The Dogs, we often recommend Thundershirts for dogs who are anxious for whatever reason. It can be particularly helpful for dogs who are freaked out during storms. For many anxiety matters, sometimes I think they can help, and sometimes I think they don’t do much. But they can’t hurt. And dogs do look cute in them.
It’s unclear why Thundershirts can be effective. It seems like it’s similar to whatever calms babies when they’re swaddled. I often liken it to having a sheet on you when you’re asleep, even if you aren’t cold. We take it for granted because we wear clothes all the time, but a light pressure on the body can certainly be comforting.
Dr. Temple Grandin has written a lot about the hug machine she made for herself as a kid. It was based on a device used to calm cows. She is autistic, and it seems that this kind of device has helped a lot of autistic kids. I don’t think dogs would like it, but if clothes aren’t working to comfort you, there’s always this.