I used it when my filly was bitten and the hair was absolutely NOT growing back. It had been three weeks since it had happened with no hair growth. I started using MTG on it, and a week later the hair was over 50% grown back so I'm definitely a fan! I didn't use it on her mane and tail though since they were already full. I did use it just as a 'last resort' not thinking it would help, with some serious dandruff (as in the entire neck looked like it was snowing and felt scaly) and no joke, it cleared it up 100% in a week. It had to be re-applied once a week though to keep her skin soft.
The only think I did not like about it was how greasy it makes the fur/base of mane look and feel. It has to be washed out, not brushed out, to go away completely BUT it doesn't have to be washed out before reapplication, so if you don't mind greasy looking mane occasionally its fine!
the hairless bite immediately after I discovered it:
the hair loss from bites/rubbing against things three weeks after it happened...STILL almost hairless O_O
about a week after applying the MTG three times (granted I used a lot...LOL) sorry, she's a little dirty but as you can see, hair growth!
This is how greasy it looks after application though. (I put it on her WHOLE neck) Yuck.
pardon her ribbiness, she had to be stalled for a month (long story) and after coming from a 24/7 turn out, she took it pretty hard and lost some weight.