Calcium is an essential mineral that supports bone and joint health. It is used as a supplement, most typically as calcium carbonate, to assist in preserving bone density especially when dietary calcium intake is inadequate. In the present study we examined the effect of five varied calcium sources, three natural and two synthetic, on stimulation, proliferation and mineralization of cultured human osteoblast cells. A MTT assay using cultured human fetal osteoblast cells (hFOB 1.19) was used to determine the effective proliferative dose for salmon collagen bone calcium (0.25 mg/ml). Elemental calcium equivalence was used to select the appropriate doses for algae calcium (0.14 mg/ml), eggshell powder (0.16 mg/ml), calcium citrate (0.22 mg/ml) and calcium carbonate (0.13). Alkaline phosphatase activity, DNA synthesis rates and calcium ion deposition were evaluated after incubation under different conditions and harvesting the cells. Alkaline phosphatase activity, DNA synthesis rates and calcium ion deposition rates were all highest for the natural salmon bone collagen calcium, followed by algae calcium. The eggshell powder, calcium citrate and calcium carbonate did not exhibit significant changes from control in most of these assays. The results of these assays suggest that natural marine collagen calcium such as salmon bone collagen calcium acts as the most effective intervention on osteoblast performance and actual calcium deposition. It should be recommended as a superior supplement for improved bone and joint health function.