WTHeck? ^^ Burn their muscles?hmmm.......... Anyway, you can make your own for real cheap, and non-drying-hooves. I don't think it stays on as long,though. Here's the recipe:
Regulat hoof Polish(absorbine,etc), must be clear + any glitter you want. Not fine glitter,though. Pour as much glitter in as you think you need, start off with a little and keep adding until you get the consistency you want. Later you can try combining glitter! Any color(s)!
Of course, since you already have the Twinkle stuff, add some hoof oil/moisturizer about an hour before you put the twinkle on. That's what I think. I've never used it before,though.