Bone degenerative diseases are on the increase globally and are often problematic to treat. This has led to a demand to identify supplements that aid bone growth and formation. Aquamin is a natural multi-mineral food supplement, derived from the red algae Lithothamnion species which contains calcium, magnesium and 72 other trace minerals. It has been previously reported to increase bone formation and mineralisation. This study aimed to investigate the 28 day in vitro osteogenic response of Aquamin supplemented with Vitamin D. The osteogenic potential of MC3T3-E1 osteoblast-like cells was analysed in standard osteogenic medium supplemented with Aquamin +/- Vitamin D3, and the controls consisted of osteogenic medium, +/- Vitamin D3. Proliferation of osteoblasts, metabolic activity and cell viability did not differ between Aquamin and the osteogenic control groups. Alkaline phosphatase (ALP) levels and mineralisation were increased by the supplementation of Aquamin, and the addition of Vitamin D3 increased mineralisation for all groups. The combination of Aquamin and Vitamin D3 yielded a significant increase in ALP and mineralisation over Aquamin alone and the standard osteogenic control +/- Vitamin D3. This study demonstrates that Aquamin aids osteogenesis, and that its osteogenic response can be enhanced by combining Aquamin with Vitamin D3