The ingredients in Source Naturals Advanced Ferrochel® have been shown in studies to Enhance increase and maintain blood levels of iron, while being gentle to the stomach and colon. This product contains a form of iron that is easily absorbed and more bioavailable than other forms of iron such as ferrous sulfate. Ascorbic acid has been shown to increase the bioavailability of iron. Vitamin B-12 and folic acid have been added for additional support.