Hi Dee 2000 IU is a vitamin D3 supplement in soft gelatin capsule form, containing 2000 International Units of cholecalciferol per capsule. This supplement helps maintain healthy vitamin D levels to support bone health, calcium absorption, and immune system function. Vitamin D is essential for calcium absorption and bone mineralization. It helps prevent and treat vitamin D deficiency which can lead to bone disorders like rickets in children and osteomalacia in adults. Regular supplementation may be recommended for people with limited sun exposure, older adults, or those with certain medical conditions that affect vitamin D absorption. The 30-capsule pack provides a month's supply when taken daily.