Comparison

Calcium Citrate +D3 Regular and Oyster Shell Calcium + D

Calcium Citrate +D3 Regular (21st Century) lists 2 distinct ingredients and Oyster Shell Calcium + D (Equaline) 2 (rows of one ingredient counted once); 2 are on both labels. On the site's similarity measure, which compares ingredient lists (1 for the same list, rarer ingredients counting for more; amounts are not part of it), the two formulas score 1.00: the same ingredients, at the amounts in the table below.

Amount per serving (and % of the Daily Value)
IngredientCalcium Citrate +D3 RegularOyster Shell Calcium + D
Calcium500 mg (38%)500 mg (38%)
Vitamin D10 mcg (50%)10 mcg (50%)

Amounts are per serving as DSLD gives them: Calcium Citrate +D3 Regular, 2 tablets; Oyster Shell Calcium + D, 1 tablet. Current labels entered March 2015 and April 2012. Percentages of the Daily Value from 21 CFR 101.9. Source: NIH ODS Dietary Supplement Label Database.

Each product on its own