Sentinel Vitamin D3 1000 IU is a dietary supplement that provides a moderate dose of vitamin D3 (cholecalciferol) to support bone health, immune function, and calcium absorption. The supplement comes in a dark amber bottle to protect the contents from light degradation. Vitamin D3 is a fat-soluble vitamin that plays multiple important roles in the body, including helping with calcium absorption for strong bones and teeth, supporting proper muscle function, and maintaining a healthy immune system. The 1000 IU dosage is a common maintenance dose suitable for many adults looking to supplement their daily vitamin D intake, especially those with limited sun exposure or living in areas with less sunlight.