May help Support Bone Health With Calcium, Magnesium & Vitamin D3 Plus Co-Factors Natrol Boron Plus is a synergistic combination of three natural, highly utilizable, chelated sources of the trace mineral boron, calcium, magnesium, vitamin D3 plus trace minerals zinc, manganese,and copper. Zinc, manganese and copper are integral co-factors for several enzymes involved in bone metabolism. Studies indicate that boron improves calcium metabolism and utilization.