Hi there: When I got my horse his pasturemate had chewed off his tail. My barn manager at the time (an old gal that had forgotten more than I’ll ever know) told me to put Mane N Tail Conditioner on it and leave it in. Surprisingly it didn’t get sticky or gross, and his tail did grow back. He is part Appy so his tail isn’t the greatest but it looks pretty good! Not sure if this trick will work for just thinning hair but it is worth a try. Hope this helps!