Whether it be the composition of the hoof, the thickness of the hair or the overall sense of well-being that the horse is supposed to have, there are products out there that supposedly can help improve it. Importantly, supplements are not carefully regulated or measured for their ability to do what the manufacturer says that they will do. Supplements, at least those that are manufactured by large companies, are usually safe for your horse. However, there is generally little or no controlled data as to their effectiveness. There are many anecdotal reports about supplements, however.
Anecdotes are no substitute for scientific investigation.
Millions of dollars are spent by the horse-owning public on these products. That being said, all you, the horse owner, really care about is doing the best that you can for your horse. Presumably, you will be somewhat curious about all the things you are going to be told that you should or must give to your horse. After all, just because you want to do something for your horse doesn't mean that you want to do just anything. The purpose of this book is to help satisfy that curiosity.