Calcium
Most abundant mineral in the body; essential for bone density. FDA RDI for adults 4+ is 1,300 mg per day. MANDATORY declaration per 21 CFR 101.36(b)(2).
FDA Reference Data
About Calcium
Calcium is one of four mandatory dietary ingredients on Supplement Facts labels per FDA 21 CFR 101.36(b)(2)(i) (alongside vitamin D, iron, and potassium). FDA RDI is 1,300 mg/day for adults 4+. Elemental calcium must be declared (not the salt weight). Common forms include Calcium Carbonate (~40% elemental Ca, requires food for absorption), Calcium Citrate (~21%, absorbed with or without food), and Calcium Bisglycinate (~18%, gentle on stomach).
Common Supplement Forms
Note: When a salt form is used, the Supplement Facts panel must declare the elemental amount (e.g., “Magnesium 141 mg 34%”), not the salt weight. The salt name appears in the ingredient list below the panel. See %DV calculator for calculation details.
Frequently Asked Questions
Why is calcium mandatory on Supplement Facts labels?
FDA 21 CFR 101.36(b)(2)(i) designates calcium as one of four mandatory dietary ingredients (with vitamin D, iron, and potassium) due to its public health significance for bone health. If a supplement contains any amount of calcium, it must be declared with amount and %DV. If absent, the label must still show "Calcium 0 mg 0%".
What is the FDA RDI for calcium?
The FDA RDI for calcium is 1,300 mg per day for adults and children 4 years and older (21 CFR 101.9(c)(8)(iv)). %DV on Supplement Facts labels is calculated as: (declared elemental calcium / 1,300) × 100, rounded to the nearest whole percent.
Do I declare the salt weight or elemental calcium on my label?
FDA 21 CFR 101.36(b)(2)(ii) requires declaration of elemental calcium, not the salt weight. For example, 1,000 mg of Calcium Carbonate (~40% elemental Ca) yields 400 mg elemental calcium. The Supplement Facts panel should declare "Calcium 400 mg 31%" — not "Calcium Carbonate 1,000 mg".
Which calcium form has the highest absorption?
Calcium Citrate is well-absorbed with or without food and is preferred for older adults with reduced stomach acid. Calcium Carbonate has the highest elemental % but requires stomach acid (take with meals). Calcium Bisglycinate is gentle on the stomach and well-tolerated for daily use.
Related Solutions
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Building a supplement with Calcium?
ReguSift extracts ingredients from your COA, calculates %DV, formats proprietary blends, and generates a print-ready Supplement Facts label — including Calcium auto-formatted per FDA 21 CFR 101.36.