Ester C is the best form of Vitamin C! Non acidic, stays in your system much longer than regular vitamin C....24 hours. It has the same high amounts of bioflavonoids as American Health....it's actually the same exact amounts as American Health in every way. Solgar is high quality & has been around for a long time. I'm very happy I found this from Solgar. I use their Gentle Iron....which is easy on the stomach & non constipating. Please keep this available on Amazon...it's a great product.