Vitamins

Vitamin B12

Cyanocobalamin / Methylcobalamin

Water-soluble vitamin essential for nerve function and red blood cell formation. FDA RDI for adults 4+ is 2.4 mcg per day.

FDA Reference Data

RDI (Adults 4+)
2.4 mcg
Unit
mcg
Mandatory Declaration
No (voluntary)
Regulation
21 CFR 101.36

About Vitamin B12

Vitamin B12 is a voluntary-declaration vitamin per FDA 21 CFR 101.36(b)(2). FDA RDI is 2.4 mcg/day for adults 4+. The two most common forms are Cyanocobalamin (synthetic, stable) and Methylcobalamin (active coenzyme form). Both forms declare as "Vitamin B12" on Supplement Facts labels; the specific form may appear in the ingredient list. Supplement doses often far exceed the RDI due to low absorption (~1% via passive diffusion at high doses).

Common Supplement Forms

Cyanocobalamin
Most common, stable, inexpensive; converts to active forms in the body.
Methylcobalamin
Active coenzyme form; preferred by some practitioners; less stable.
Adenosylcobalamin
Active coenzyme form; sometimes combined with methylcobalamin.

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

What is the FDA RDI for Vitamin B12?

The FDA RDI for Vitamin B12 is 2.4 mcg per day for adults and children 4 years and older (21 CFR 101.9(c)(8)(iv)). %DV is calculated as: (declared mcg / 2.4) × 100, rounded to the nearest whole percent. Note: many B12 supplements declare amounts far exceeding the RDI (e.g., 1000 mcg = 41,667% DV) due to dose-dependent absorption.

Should I declare Vitamin B12 as cyanocobalamin or methylcobalamin on my label?

On the Supplement Facts panel, the nutrient is declared simply as "Vitamin B12" with its amount in mcg and %DV. The specific cobalamin form (cyanocobalamin, methylcobalamin, etc.) appears in the ingredient list below the Supplement Facts panel, not in the nutrient declaration row. Both forms contribute to the same "Vitamin B12" %DV calculation.

Why do B12 supplements contain such high amounts compared to the RDI?

Vitamin B12 absorption is dose-dependent via the intrinsic factor pathway (~56% of a 1 mcg dose, but only ~1% of a 1000 mcg dose via passive diffusion). Manufacturers use high doses to ensure measurable absorption. FDA permits amounts exceeding 100% DV on supplement labels; the %DV column will show very high percentages (e.g., 41,667% for 1000 mcg), which is compliant.

Building a supplement with Vitamin B12?

ReguSift extracts ingredients from your COA, calculates %DV, formats proprietary blends, and generates a print-ready Supplement Facts label — including Vitamin B12 auto-formatted per FDA 21 CFR 101.36.

Back to all ingredients