Elevate *Concentrate* Natural Vitamin E Supplement, 2lbRelated: Elevate Maintenance. Consult your Veterinarian to see which formula may be right for you. The best source of vitamin E is fresh green grass; however, the potency of vitamin E declines very quickly once forages are harvested and dried. Vitamin E cannot be synthesized by the horse; therefore, it is considered an essential nutrient. The most accurate way to determine your horses vitamin E status is to ask your veterinarian to run a simple blood