3 forms with different bioavailability + clinical use · canon pro citrate · avoid carbonate elderly · hydroxyapatite specific osteoporosis.
Ca + citric acid × 2-3
Best for
Ideal use: any 2026 pro Ca supplementation · pregnancy · elderly · chronic PPIs.
Advantages
Bioavailability +24% vs carbonate (Heaney 2018). Absorption without gastric HCl (canon elderly, PPIs, achlorhydria). Superior digestive tolerance. Citrate improves parallel Mg absorption.
Disadvantages
Expensive vs carbonate (~10-15 €/month at 500 mg/d). Doses >500 mg require multiple large tablets.
Common OTC form
Best for
Ideal use (limited): healthy young with budget · NOT elderly.
Advantages
Extreme economy (~5-8 €/month). 40% elemental Ca (vs 21% citrate) · fewer tablets equivalent dose. Also antacid.
Disadvantages
Requires gastric HCl · fails elderly, PPIs, achlorhydria. Constipation, gas. Take with food to absorb.
Bone-derived natural matrix form
Best for
Ideal use: confirmed osteoporosis · under rheumatology/endocrinology.
Advantages
Natural matrix with Ca + P + Mg + collagen protein matrix · imitates bone structure. Some studies suggest superior BMD vs isolated Ca.
Disadvantages
Expensive (~25-40 €/month). Limited availability in Spain. Bovine origin (vegetarians avoid).
Ideal use: any 2026 pro Ca supplementation · pregnancy · elderly · chronic PPIs.
Ideal use (limited): healthy young with budget · NOT elderly.
Ideal use: confirmed osteoporosis · under rheumatology/endocrinology.
3 forms with different bioavailability + clinical use · canon pro citrate · avoid carbonate elderly · hydroxyapatite specific osteoporosis.