Agitated, nervous horses that are normally well behaved may benefit from nutritional calming. But before deciding, make sure your horse isn't stressed by things that you can control. Restricting forage where the stomach becomes empty is the main cause of behavioral issues.
The number of calming supplements on the market is daunting
Each contains specific nutraceuticals designed to calm your horse, but it is difficult to know which one to choose. Below are supplements that have been shown to be effective and safe for your horse. For more information on these, see "Dr. Getty's Four Favorite Calming Ingredients," as well as the Resource Library on Stress Prevention.