Feed 1-2 wafers per day.
In an attempt to see how well this worked, I put one horse on it and left one with similiar color and markings off the wafers. In one month, there is a marked difference! The one on the wafer has a coat that is shiny (and her's is typically dull), and, despite being out in the sun, her dark spots have remained dark. Only downside I have found is that not all my horses will eat them - just the ones who aren't picky about their food. I definitely recommend it!