NOW Foods Vitamin C Crystals, 8 Ounces

 Fine Ascorbic acid is a bioavailable form of Vitamin C in a powder form, so it can be combined with other powdered supplements or dissolved in liquid for easy ingestion.

 From the FDA's website: "Some scientific evidence suggests that consumption of antioxidant vitamins may reduce the risk of certain forms of cancer. However, FDA has determined that this evidence is limited and not conclusive."