A randomized, double-blind clinical study performed in Germany reported that Ester-C calcium ascorbate caused fewer epigastric (stomach) discomfort than regular Vitamin C. Vitamin C is the most important water-soluble antioxidant in the body, but the body cannot make it – it must be taken in by foods or supplements. But high doses of the ascorbic acid form of Vitamin C – called AA – can cause abdominal cramping, nausea, heartburn, and diarrhea. Ester-C is more rapidly absorbed, which researchers believe may contribute to its ease on the stomach. Seventy-two percent of study participants rated Ester-C tolerability "very good." AA was ranked "very good" by only about half the participants – a "statistically significant" difference, according to researchers. For more information go to the Advances in Therapy, Jan/Feb 2006, Vol. 23. Source: Advances in Therapy, Jan/Feb 2006, Vol. 23.