Calcium citrate

Calcium citrate is a calcium salt of citric acid commonly used as a dietary supplement and medication to treat or prevent calcium deficiency [1.1.2, 1.3.1]. Unlike calcium carbonate, it does not require gastric acid for absorption, making it particularly useful for patients with achlorhydria or those taking proton pump inhibitors [1.2.1, 1.3.3]. Biologically, it serves as a source of calcium ions (Ca2+), which are critical for bone mineralization, muscle contraction, and neurotransmitter release [1.2.4, 1.3.1]. In the context of disease, it is primarily indicated for osteoporosis, hypoparathyroidism, and rickets [1.1.2, 1.1.4]. While it is a therapeutic agent, it is not a biological target itself; rather, the calcium ions it releases interact with targets such as the calcium-sensing receptor (CaSR) and voltage-gated calcium channels [1.1.2, 1.2.2].

Other names

Tricalcium dicitrateCitracalCalcitrateCalcium citrate tetrahydrateTribasic calcium citrate

Calcium citrate provides elemental calcium which is absorbed in the intestine and increases plasma calcium levels. This stimulates the calcium-sensing receptor (CaSR) on parathyroid cells, leading to a decrease in parathyroid hormone (PTH) secretion and a subsequent reduction in bone resorption. Additionally, calcium ions serve as essential cofactors for various enzymes and proteins involved in muscle contraction, nerve impulse transmission, and the blood coagulation cascade.