We use superior science to make smarter formulas like Jarrow Formulas® Vitamin D3 5000 IU. It provides cholecalciferol, which is the form produced by the (human) skin in response to UVB exposure (sunlight), and may also improve Vitamin D status better than equivalent amounts of ergocalciferol. Vitamin D3 is converted to calcitriol in the body, which enhances dietary calcium and phosphorous absorption, supports production of osteocalcin (an important structural protein in bone), and supports a healthy immune response.* *These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.