In the present study, the effects of aspartic acid and glutamic acid on the solubility and absorption of calcium gluconate and calcium citrate, two common forms of calcium supplements, were investigated. The results revealed that both amino acids increased the solubility of calcium gluconate and calcium citrate by binary or ternary complex formation, not by ligand exchange, as confirmed by calcium specification and density function theory calculations. The same mechanism applied to the calcium binding peptides. Furthermore, the addition of aspartic acid and glutamic acid resulted in a remarkable increase in calcium absorption compared to calcium gluconate and calcium citrate alone. This might be due to the altered properties (solubility, stability, and charges) of the complexes, as well as their enhanced interaction with the calcium channel TRPV6 through hydrogen bonding. Our findings provide new insights into the development of effective calcium supplementation strategies based on calcium-amino acids/calcium binding peptides complexes.