Dr. Peter D'Adamo designed four different mineral formulas using unique cofactors and micro-mineral ratios specific to each blood type. Designed by Dr. Peter D’Adamo Phytocal O features a unique natural source of highly absorbable calcium: The small red seaweed called Maerl found only in the isolated areas off the pristine coast of southwest Ireland. All Phytocal multi-mineral formulas feature Maerl-based sea calcium the only natural source of calcium with a broad enough buffering range to work effectively amid the widely differing digestive capabilities of each blood type. Maerl is composed of a wide variety of essential nutrients including calcium and trace amounts of magnesium boron and zinc. Maerl’s unique structure gives it great versatility and insures a phenomenal rate of bioavailability and utilization. Because each blood type possesses variable assimilation capabilities and requires differing cofactor and trace mineral necessities Dr. D'Adamo designed four different mineral formulas using unique cofactors and micro-mineral ratios specific to each blood type. Phytocal O Phytocal O features balanced levels of the micro and macro minerals magnesium iron copper and zinc; manganese to help insure healthy joint and ligament function and micro-trace amounts of iodine to enhance thyroid function. Phytocal O also features nettle leaf Urtica dioica an important aid to proper intestinal assimilation.