The combination of vitamin D3 and vitamin K2 in these Nature's Plus capsules is designed to maximize bone health and the immune system. Vitamin D3, also known as cholecalciferol, contributes to the maintenance of normal bones and teeth, and plays an important role in immune system function. Each capsule contains 25 µg of vitamin D3 (equivalent to 1,000 IU), representing 500% of the Nutrient Reference Value (NRV). Meanwhile, vitamin K2 (menaquinone MK-7) complements the action of D3, as it is recommended to consume 100 micrograms of K2 for every 1,000 IU of D3 for optimal health. Each capsule contains 100 µg of vitamin K2, representing 133.3% of the NRV.