Reading a Vitamin Label: Percent Daily Value, "As" Forms, Amounts Above 100% and Added Ingredients
How to read a US Supplement Facts panel: serving size, percent Daily Value, "as" forms, amounts above 100%, other ingredients, and what a label cannot tell you about quality.
Content last updated . This page has not been medically reviewed.
This page describes the US label. Other countries have their own rules. For a general checklist see reading supplement labels, and for side-by-side comparison see comparing supplement labels and cost per serving. If a child may have swallowed a vitamin product, call Poison Help at 1-800-222-1222 (US), or 911 if the child is unwell; see poisoning: what to do first.
Parts of the panel
| Part | What the rules say | Source |
|---|---|---|
| Serving size and servings per container | Serving size uses a term suited to the product, such as tablets, capsules or packets. [2] Servings per container sit under it. [2] | 21 CFR 101.36 |
| Amount per serving | The amount shown is the weight of the nutrient itself, not of the ingredient that supplies it. [2] | 21 CFR 101.36 |
| "As" or "from" sources | A source may be named in parentheses, for example "Calcium (as calcium carbonate)". [2] | 21 CFR 101.36 |
| % Daily Value (%DV) | Based on values for adults and children 4 or more, unless the product is made for another group, which must be stated. [2] | 21 CFR 101.36 |
| "Daily Value not established" | Ingredients with no reference amount carry a symbol and this statement instead of a percentage. [2] | 21 CFR 101.36 |
| Other ingredients | Fillers, binders, excipients, preservatives, sweeteners and flavorings. [3] | FDA |
The order of vitamins on a panel follows a set list, starting with vitamin A, vitamin C, vitamin D and vitamin E. [2]
What percent Daily Value means
FDA says the %DV shows how much a nutrient in one serving contributes to your daily diet. [4] As a general guide, 5% DV or less per serving is low and 20% DV or more is high. [4] That guide describes how much a serving contributes. It is not a safety rating. The Daily Value is a label reference, not a personal target, and it is different from an upper limit; see RDA, AI, DV and UL. Label DVs for each vitamin are in vitamin intake reference tables.Amounts above 100%
Nothing stops a supplement from containing more than 100% of the DV. FDA's own worked examples include products at 117%, 119% and 170% of the folate or vitamin A DV. [5] A high percentage can be fine, or not, depending on the nutrient, the form and the person.Upper limits are set separately and differ between countries. For vitamin B6 the US label DV is 1.7 mg, [6] the NHS says not to take more than 10 mg a day in supplements unless a doctor advises it, [7] and Health Canada lists an adult upper level of 100 mg. [8] A %DV figure therefore cannot tell you where any of those limits sit. Talk to a clinician or pharmacist before using products that stack several vitamins at high percentages.
Forms: reading the "as" and the parentheses
- Vitamin D: declared in mcg; IU may follow in parentheses. [2]
- Vitamin A: a label may state the percent present as beta-carotene, for example "90% as beta-carotene". [2] Beta-carotene and preformed vitamin A are counted differently; see vitamin units explained.
- Folate: shown as mcg DFE, with the amount of folic acid in parentheses when folic acid is added. [6] Example: 200 mcg of folic acid counts as 340 mcg DFE. [5] See folate vs folic acid and methylfolate.
- Proprietary blends: a blend is listed under the term "Proprietary Blend" or another descriptive name. [2] For ingredients without a Daily Value, only one total weight is shown for the blend, and they are listed in descending order of predominance by weight, so each ingredient's own amount is not stated. [2]
What a label cannot show
- Exact content: US rules accept reasonable excesses over labeled amounts within good manufacturing practice. [2]
- Pre-sale review: FDA does not have the authority to approve dietary supplements before they are marketed, [3] and it does not routinely analyze their content. [3]
- Quality words: "standardized", "verified" or "certified" on a label do not necessarily guarantee quality. [1] See quality testing and certifications.
- Disease claims: products sold as supplements cannot lawfully be represented as treating or preventing a specific disease. [3] Structure/function claims carry a disclaimer that the statement has not been evaluated by FDA. [3]
Frequently asked questions
What does "% Daily Value" mean on a supplement?
It shows how much of a nutrient one serving provides compared with the label reference amount. [4] The reference is for adults and children 4 or more unless the label names another group. [2]
Is more than 100% of the Daily Value dangerous?
Not automatically, and not automatically safe. Percentages above 100 appear on real products, [5] while upper limits are set separately by each country's authorities and differ. [7][8] Ask a clinician or pharmacist about your own situation.
What does "as" mean in "Calcium (as calcium carbonate)"?
It names the ingredient that supplies the nutrient. The amount shown is the weight of the nutrient, not the weight of the source. [2]
What are "other ingredients"?
Substances such as fillers, binders, excipients, preservatives, sweeteners and flavorings. [3] People with allergies or sugar concerns should read them.
Can a label prove a product is pure and accurate?
No. Companies are responsible for accurate labels, but FDA does not approve supplements before sale. [3] The NCCIH notes that the product may differ from what the label says. [1]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety points before you rely on a label
- Medicines: some supplements change how medicines are absorbed or broken down; for example vitamin E can thin the blood like warfarin and aspirin. [9] Check medication interactions.
- Pregnancy, breastfeeding and children: many supplements have not been tested in these groups. [1]
- Surgery: some supplements may affect bleeding or anesthesia, so tell the surgical team about every product. [1]
- Kidney or liver conditions: the sources read for this page say supplements can pose risks with certain medical problems, [1] but do not give vitamin-specific advice. Ask your clinician.
References
- National Center for Complementary and Integrative Health (NIH). Using Dietary Supplements Wisely. Read 2026-10-23.
- US Code of Federal Regulations. 21 CFR 101.36, Nutrition labeling of dietary supplements, eCFR text dated 2025-01-02. Read 2026-10-23.
- US Food and Drug Administration. Information for Consumers on Using Dietary Supplements (questions and answers). Content current as of 08/27/2026. Read 2026-10-23.
- US Food and Drug Administration. Daily Value on the Nutrition and Supplement Facts Labels. Content current as of 03/05/2024. Read 2026-10-23.
- US Food and Drug Administration. Converting Units of Measure for Folate, Niacin, and Vitamins A, D, and E on the Nutrition and Supplement Facts Labels: Guidance for Industry. August 2019. Read 2026-10-23 (text extracted from the PDF; some Greek letters were lost in extraction).
- US Code of Federal Regulations. 21 CFR 101.9, Nutrition labeling of food, eCFR text dated 2025-01-02. Read 2026-10-23.
- NHS (UK). Vitamin B (B vitamins and folic acid). Page last reviewed 3 August 2020. Read 2026-10-23.
- Health Canada. Dietary reference intakes tables: Reference values for vitamins. Page dated 2025-11-19. Read 2026-10-23 through a web-fetch summary tool because the page would not download directly; the figures are as that tool returned them and should be checked against the table.
- US Food and Drug Administration. Mixing Medications and Dietary Supplements Can Endanger Your Health. Content current as of 06/02/2022. Read 2026-10-23.