Minerals
Calcium (Citrate / Hydroxyapatite)
Also known as: Calcium citrate · Calcium carbonate · Calcium hydroxyapatite · MCHA
The most abundant mineral in the body. Supplementation is most important for those avoiding dairy and for postmenopausal women. Citrate absorbs without food; carbonate needs stomach acid.
Effective Dose
500–1200mg / day
per clinical evidence
Evidence Level
Strong
Minerals
Mechanism
Structural bone mineral, muscle contraction signalling, nerve transmission
primary action
Best For
Bone density
PMS symptoms, Muscle function, Vegan/dairy-free diets
This profile is for informational purposes only and does not constitute medical advice. Consult a qualified healthcare professional before starting any supplementation, especially if you have pre-existing conditions or take medications.
What Is Calcium (Citrate / Hydroxyapatite)?
Calcium constitutes ~99% of bone mineral as hydroxyapatite crystals and 1% in blood/soft tissue where it performs critical signalling roles. Bone is a metabolically active calcium reservoir — maintained by the balance of osteoblast (building) and osteoclast (resorption) activity, regulated by PTH, vitamin D, and calcitonin.
How It Works: The Science
Intracellular calcium transients (released from SR by IP₃ or ryanodine receptor activation) trigger muscle contraction, neurotransmitter release, and cell signalling cascades. PTH maintains blood calcium by stimulating osteoclastic bone resorption and renal calcium reabsorption when dietary intake is insufficient — at the cost of bone density.
Primary Mechanism
Structural bone mineral, muscle contraction signalling, nerve transmission
Evidence-Based Benefits
Dosage Guide
Effective Dose
500–1200mg / day
500–1200mg/day in split doses (maximum 500mg absorbed per dose). Citrate: absorbed with or without food, preferred for those on acid-reducing medications. Carbonate: requires stomach acid — take with meals. Microcrystalline hydroxyapatite (MCHA): bone-specific form with best evidence for bone density.
Safety Profile & Side Effects
High supplemental doses (>1500mg/day) may increase cardiovascular risk — take only what dietary intake doesn't cover. Calcium inhibits iron, zinc, and magnesium absorption — take at separate times.
Who Should (and Shouldn't) Take It
Those avoiding dairy (vegans, lactose intolerant), postmenopausal women, adolescents during peak bone mass accumulation, and women with PMS. Most adults can meet needs from diet — supplement only the gap.
Frequently Asked Questions
Related Ingredients
Medical Disclaimer
Ingredient profiles are for informational purposes only and do not constitute medical advice. Consult a qualified healthcare professional before starting any supplementation, especially if you have pre-existing conditions or take medications. Full disclaimer →