Ultra Cruz Equine Vitamin C (ascorbic acid) is a water-soluble vitamin that functions as an antioxidant in cellular metabolism. Ascorbic acid has been found to stimulate the production of collagen. In addition, ascorbic acid facilitates iron absorption in the small intestine and supports hemoglobin synthesis. Daily oral Administration of 4. 5 G to Horses may increase ascorbic acid plasma concentrations and support the health of your Horse.