Progressive Labs OPA Orthophosphoric Acid 2 ozDescription Phosphorus supplement for support of bones and teeth.* Next to calcium, phosphorus is the most abundant mineral in the body. Approximately 85% of phosphorus in the body can be found in bones and teeth and roughly 10% circulates in the bloodstream. Ingredients Amount Per Serving Vitamin B 2 (Riboflavin)Amount Per Serving: 100 mcg Phosphorus From orthophosphoric acid 395 mgAmount Per Serving: 125 mg InositolAmount Per Serving: 21 mg Other