I just started using M-T-G on my horse's tail with the hopes that a miracle will happen :) I will be applying it once a week as close to his tail bone as possible.
That being said, M-T-G is pretty miraculous at clearing scratches, rain rot, girth itch over night and the bottle says it helps with hair growth (up to 3 inches a month, so it says). So I'm figuring if it works like it said it would on skin conditions, there's a fair chance it will do wonders for hair growth (fingers crossed). Fun fact: M-T-G smells terrible and make sure you wear gloves when you use it, otherwise your hands smell like burnt sulfer and wood. Also, make sure you get it as close to the roots of the hair as possible instead of the actual strands of hair (you might want to do a small skin test to make sure your pony doesn't have a sensitivity reaction).