Gentle. Fast-Acting. Long-Lasting. Plus 200 mg Bioflavonoids Concentrate and Indole-3-Carbinol. Reacta-C is a highly advanced patent-pending Vitamin C formula that provides a reacted complex of Strontium Calcium Ascorbate with L-Threonate. We also included other key ingredients - Bioflavonoids Indole-3-Carbinol and a highly synergistic Vitamin C support base - for maximum bioavailability and effectiveness. This non-acidic formula is designed to be gentle on the stomach and digestive system while providing optimal benefit to the body.