KER PreserveMuscle Health and Antioxidant Supplement for Performance Horses Preserveis a scientifically formulated supplementary source of natural vitamin E, organic selenium, magnesium, and vitamin C. Why use Preserve? Aids in reducing muscle damage in working horses Contains natural vitamin E, a powerful antioxidant, which is more biologically potent than synthetic forms Contains organic selenium, which is research proven to be more bioavailable than inorganic