Coral calcium hasn’t provided many mind-blowing advances for the research community. The Department of Orthopaedic Surgery at Mahidol University in Bangkok collected samples of calcium carbonate salts and analyzed them for lead, cadmium and mercury. Every sample of the calcium carbonate contained lead. [2] A Japanese study with only 12 volunteers examined the effects of ingesting coral calcium via a cracker. Researchers did note a few interesting notes about observed absorbability but largely concluded that the data set was inconclusively small. [3]
Surprisingly, coral calcium has been shown to be useful in at least one application. A German surgeon had reported successfully using natural coral calcium for maxillofacial surgery bone grafting applications. [4]