Another thing that works for me is plain Conditioner....rub it into your horses dry tail from top to bottom. And that's it....The other stuff probably work wonders but I have never tried it...
I buy my conditioner at the dollar store.
MTG is the best stuff that I have ever used. I have a mini mare that we show in halter and she had a tail that was literally 2 feet on the ground behind her, I had to keep it tied up so she wouldn't walk on it. Then I had some goats and they ate it overnight when the escaped from their pasture, and they ate it almost to the tailbone. It has been 3 months since then and her tail is happily growing and is officially past her hocks and is just as thick as it was before. I put it on once every week and cover her tailbone in it and run my fingers through the rest of her tail and it works great! I would say I have gotten 9 inches of tail growth in the past 3 months on this mare. I have also used it on several of the other horses and have had similiar results with them.
Regular horse or people conditioner and vet wraps it. I used to use MTG until a few months ago when someone on the forum brought up the fact that it can cause burns if applied to certain areas of the skin. Knowing that it is because of a chemical in the product makes me think its simply not safe enough for my 2 babies. Conditioner and showsheen to help with the breakage is the best thing out there. I will try to post photos of my boy's tail.