Supplement Label Index

Dicalcium Phosphate vs. Calcium Citrate

Among 5,062 on-market calcium products with an identifiable primary form, 24.2% use Dicalcium Phosphate (1,226 products) and 20.3% use Calcium Citrate (1,027).

Dicalcium PhosphateCalcium Citrate
Quality tierUnratedTier 1
Calcium by weight23.3%21.1%
Share of market24.2%20.3%
On-market products1,2261,027
Median declared dose98.13 elemental mg
middle half: 50–166
125 elemental mg
middle half: 50–400
Most common brandsThe Vitamin Shoppe, DC, Mason NaturalBluebonnet, Pure Encapsulations, Bariatric Advantage

Doses are declared per serving in elemental mg. “By weight” is the share of the ingredient that is the nutrient itself (e.g. elemental magnesium in a magnesium salt).

Why Dicalcium Phosphate is unrated

No specific human comparative bioavailability study vs carbonate/citrate was verified.

Source: uncertain -- needs review

Why Calcium Citrate is tier 1

Meta-analysis of 15 studies (184 subjects): absorption significantly higher than carbonate by ~20-27%, fasting and with meals; does not require gastric acid.

Source: Sakhaee K et al. 1999, PMID 11329115

Tiers summarize published comparative bioavailability or outcome evidence for each form (see methodology). This page describes the market; it is not a recommendation to take either form. Talk to a clinician about what's right for you.

Other calcium comparisons