Ostelin Vitamin D3 1000IU comes in a small, easy to swallow capsule that provides a daily dose of vitamin D3, the form that is naturally produced in the body. Vitamin D assists the body in calcium absorption and is required throughout life as it helps to maintain strong bones and support muscle function, which may reduce the risk of falls. Vitamin D requirements also increase in pregnant women due to calcium deposition and bone mineralisation in the developing baby. Many Australians do not achieve sufficient Vitamin D levels due to lack of sun exposure. Vitamin D supplementation may help maintain a healthy immune system.