Supplement Label Index

Dicalcium Phosphate vs. Calcium Ascorbate

Among 5,062 on-market calcium products with an identifiable primary form, 24.2% use Dicalcium Phosphate (1,226 products) and 8.3% use Calcium Ascorbate (418).

Dicalcium PhosphateCalcium Ascorbate
Quality tierUnratedUnrated
Calcium by weight23.3%9.4%
Share of market24.2%8.3%
On-market products1,226418
Median declared dose98.13 elemental mg
middle half: 50–166
56 elemental mg
middle half: 29–108
Most common brandsThe Vitamin Shoppe, DC, Mason NaturalMH Michael's Health Naturopathic Programs, American Health, NOW

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 Ascorbate is unrated

Used primarily as a buffered vitamin C source; no calcium-specific bioavailability study was found.

Source: uncertain -- needs review

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