Calcium Citrate vs Microcrystalline Hydroxyapatite
How calcium citrate and microcrystalline hydroxyapatite differ in elemental content, absorption, tolerance, and cost.
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Side by Side
| Calcium Citrate | Microcrystalline Hydroxyapatite (MCHC) | |
|---|---|---|
| Elemental content | 21.1% elemental calcium | Varies by product |
| Absorption | Moderate | Variable |
| How it is absorbed | Dissolves without stomach acid, so absorption holds up when fasting, on PPIs, and after gastric bypass. | Ground bovine bone with calcium, phosphorus, and bone matrix proteins. Absorption data are limited. |
| Typical dose | 200-500 mg elemental per dose | Per product |
| Common uses | low stomach acid, after bariatric surgery | marketed for bone health |
| Side effects | Less constipation than carbonate. | Constipation. |
| Cost | Moderate | Moderate |
| Also called | calcium citrate malate (related) | hydroxyapatite, bone meal concentrate |
| Labels in index | 1,061 | 149 |
When to Choose Calcium Citrate
Choose calcium citrate when you take PPIs, have had gastric bypass, or take calcium between meals. About 21% calcium, so tablets are larger or more numerous for the same dose.
Calcium Citrate
The form that does not depend on stomach acid. Bigger tablets, gentler on the gut.
What to look for: Elemental calcium per serving stated; 200-500 mg per dose. The choice with PPIs or after bariatric surgery.
Find on iHerb Affiliate linkWhen to Choose Microcrystalline Hydroxyapatite (MCHC)
There is rarely a reason to choose microcrystalline hydroxyapatite: carbonate or citrate are better studied. Bone-derived products have carried lead in past testing; look for certification.
Microcrystalline Hydroxyapatite (MCHC)
There is rarely a reason to choose microcrystalline hydroxyapatite: carbonate or citrate are better studied.
What to look for: Microcrystalline Hydroxyapatite named on the Supplement Facts panel, with the amount per serving stated.
Find on iHerb Affiliate linkProducts on Titrate
In Titrate's index of NIH label data, 1,061 labels named as calcium products list calcium citrate and 149 list microcrystalline hydroxyapatite.
Calcium does not have its own search category yet. Each product above links to its full label in the NIH database.
Related
References
NIH Office of Dietary Supplements. Calcium: Fact Sheet for Health Professionals.
Recker RR. Calcium absorption and achlorhydria. N Engl J Med. 1985;313(2):70-73.
Heaney RP, Dowell MS, Bierman J, Hale CA, Bendich A. Absorbability and cost effectiveness in calcium supplementation. J Am Coll Nutr. 2001;20(3):239-246.
Jackson RD, LaCroix AZ, Gass M, et al. Calcium plus vitamin D supplementation and the risk of fractures. N Engl J Med. 2006;354(7):669-683.
Bolland MJ, Avenell A, Baron JA, et al. Effect of calcium supplements on risk of myocardial infarction and cardiovascular events: meta-analysis. BMJ. 2010;341:c3691.
Bolland MJ, Grey A, Avenell A, Gamble GD, Reid IR. Calcium supplements with or without vitamin D and risk of cardiovascular events: reanalysis of the Women's Health Initiative limited access dataset and meta-analysis. BMJ. 2011;342:d2040.
Kopecky SL, Bauer DC, Gulati M, et al. Lack of evidence linking calcium with or without vitamin D supplementation to cardiovascular disease in generally healthy adults: a clinical guideline from the National Osteoporosis Foundation and the American Society for Preventive Cardiology. Ann Intern Med. 2016;165(12):867-868.