VITAMINS & SUPPLEMENTS · GUIDE
Supplement Formula Glossary: Terms From Overage to Proprietary Blend
Plain-language definitions of supplement label and formula terms, from adequate intake and Daily Value to overage and proprietary blend, each linked to the page that covers it.
Content last updated . This page has not been medically reviewed.
Back to Supplement FormulasThis glossary explains words you meet on supplement labels, in formula guides and in official advice. Each entry says where the definition comes from. Some terms, such as "overage", are not defined in the official pages we read, and the entry says so rather than guessing. Definitions are about the United States unless a body from another country is named. This is information, not advice: a clinician or pharmacist can tell you what is right for you.
How to use this page
Look up the term, read the short definition, then follow the link for the full guide. If you want a label walk-through first, start with Reading Supplement Labels or the Supplement Facts panel guide.
Amounts and reference values
| Term | What it means | Where to read more |
|---|---|---|
| Adequate intake (AI) | EFSA (the European Food Safety Authority) describes it as a recommendation used "when there isn't enough data to calculate an average requirement". [1] | More about Adequate intake (AI) → |
| Population reference intake (PRI) | EFSA defines it as the intake "likely to meet the needs of almost all healthy people in a population". [1] | More about Population reference intake (PRI) → |
| Tolerable upper intake level (UL) | EFSA describes it as the maximum amount of a nutrient that can be consumed safely over a long period of time. [1] A UL is a limit for a stated group, not a target. | More about Tolerable upper intake level (UL) → |
| Daily Value (DV) | A reference amount used on US labels. FDA says DVs are "the recommended amounts of nutrients to consume or not to exceed each day". [2] On a label it is a yardstick, not a personal requirement. | More about Daily Value (DV) → |
| Percent Daily Value (%DV) | How much a nutrient in one serving contributes to the Daily Value. FDA gives a general guide: 5% DV or less is low and 20% DV or more is high. [2] | More about Percent Daily Value (%DV) → |
| Serving size | FDA's labeling guide says one serving equals the maximum amount recommended on the label per eating occasion. [3] Every amount on the panel is "per serving", so a product with a larger serving shows larger numbers. | More about Serving size → |
| Elemental amount | The weight of the nutrient itself, not the compound that carries it. FDA's guide gives calcium as the example: list the weight of calcium, not of the calcium carbonate source. [3] | More about Elemental amount → |
| Source ingredient | The compound a nutrient comes from (for example a salt). FDA says you may list the source of a dietary ingredient in the panel. [3] | More about Source ingredient → |
Units
| Unit | What it means | Source |
|---|---|---|
| mcg, mg | Micrograms and milligrams. A microgram is 1,000 times smaller than a milligram. [4] | NHS |
| IU | International units, a measure used for some vitamins. For vitamin D, the NHS says 1 microgram equals 40 IU. [5] Conversion factors differ by vitamin, so do not assume this one applies to others. | NHS |
| mcg RAE | Micrograms of retinol activity equivalents, the unit FDA uses for vitamin A Daily Values. [2] | FDA |
| mcg DFE | Micrograms of dietary folate equivalents, the unit FDA uses for folate and folic acid. [2] | FDA |
| mg NE | Milligrams of niacin equivalents. [2] | FDA |
Vitamin groups
| Term | What it means | Source |
|---|---|---|
| Fat-soluble vitamins | Vitamins A, D, E and K. MedlinePlus says they are stored in the liver, fatty tissue and muscles. [9] | MedlinePlus |
| Water-soluble vitamins | Vitamin C and the B vitamins. MedlinePlus says leftover amounts of most leave the body through the urine, with vitamin B12 an exception. [9] "Water-soluble" does not mean harmless. | MedlinePlus |
| Folate and folic acid | FDA lists them together for the Daily Value (400 mcg DFE on US labels). [2] The two are not identical forms, so check which one a study or label names. | Folate |
Terms with no official definition in our sources
| Term | What we found |
|---|---|
| Overage | The word is not defined in the official pages we read, so we do not define it here from memory. FDA's labeling guide says an added ingredient must be present at 100 percent of the declared amount, and a naturally occurring one at 80 percent. [3] What a label amount means for a given product is a question for the maker or a clinician or pharmacist. |
| "Bioavailable", "clinically proven", "pharmaceutical grade", "clean" | Marketing wording. Not described in the sources we read as official terms. See clean and natural claims. |
| Third-party tested | Not defined in the sources on this page. See what third-party testing can and cannot show. |
Frequently asked questions
What is the difference between an Upper Level and a Daily Value?
A tolerable upper intake level is the highest amount EFSA describes as safe over a long period for a stated group. [1] A Daily Value is a label reference amount on US labels. [2] They answer different questions and come from different bodies.
Does "water-soluble" mean a vitamin cannot be harmful?
No. MedlinePlus says excess amounts of most water-soluble vitamins leave the body through urine, [9] but that statement does not say every high amount is safe. Official bodies set upper levels for several water-soluble nutrients, such as EFSA's level for vitamin B6. [1]
Is a proprietary blend illegal?
Not as described in the sources we read. FDA's labeling guide explains how a blend must be listed, with the total weight and the ingredients in order of predominance. [3] The point for readers is that individual amounts inside a blend may not be shown.
What does overage mean on a supplement?
We did not find an official definition in the pages we read. What those pages do say is that FDA's guide sets 100 percent of the declared amount for added ingredients. [3]
Where do I report a problem with a supplement?
FDA says first to contact or see your health care provider, then you or your provider can report the adverse event to FDA. [6] See side effects and reporting.
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.
Label and regulation terms
| Term | What it means | Where to read more |
|---|---|---|
| Dietary supplement | A product intended for ingestion that contains a "dietary ingredient" intended to supplement the diet, as defined by the US Dietary Supplement Health and Education Act of 1994. [6] | More about Dietary supplement → |
| Dietary ingredient | FDA says the term includes vitamins and minerals, herbs and other botanicals, and amino acids, among others. [6] | More about Dietary ingredient → |
| Other dietary ingredients | In FDA's labeling guide, dietary ingredients with no Daily Value, such as phosphatidylserine. [3] | More about Other dietary ingredients → |
| Other ingredients | Items not in the Supplement Facts panel but listed beneath it. FDA says they include fillers, binders, excipients, preservatives, sweeteners and flavorings. [6] | More about Other ingredients → |
| Proprietary blend | A group of ingredients under one name. FDA's guide says the blend's total weight is listed, with its ingredients in descending order of predominance by weight. [3] The individual amounts inside the blend are not required. | More about Proprietary blend → |
| Structure/function claim | FDA's labeling guide describes it as a statement about the role of a nutrient or dietary ingredient intended to affect the structure or function in humans. [7] | More about Structure/function claim → |
| Disclaimer | Wording that must accompany a structure/function claim: "This product is not intended to diagnose, treat, cure, or prevent any disease." [7] | More about Disclaimer → |
| Health claim | FDA says it describes the effect a substance has on reducing the risk of a disease, and it requires FDA evaluation and authorization before use. [7] | More about Health claim → |
| New dietary ingredient | An ingredient that meets the definition of a dietary ingredient and was not marketed in the United States before October 15, 1994. [6] | More about New dietary ingredient → |
| Adulterated / misbranded | FDA's examples: a product is adulterated if an ingredient is unsafe, and misbranded if its labeling is false or misleading. [8] | More about Adulterated / misbranded → |
| Adverse event | A harmful effect or illness thought to be related to a supplement. FDA says to contact your health care provider first and that it wants to hear about such problems. [6] | More about Adverse event → |
Safety terms worth knowing
FDA says it does not have the authority to approve dietary supplements before they are marketed. [6] NCCIH adds that dietary supplements may interact with medicines or pose risks for people with certain medical problems or before surgery. [10] Before using a supplement, FDA advises talking to a doctor, pharmacist or other health care professional. [6] For a short summary, see the safety quick reference and the frequently asked questions.
References
- Dietary reference values (EFSA, European Union). Dietary reference values (EFSA, European Union). Read 2026-10-23.
- Daily Value on the Nutrition and Supplement Facts Labels (FDA, US). Daily Value on the Nutrition and Supplement Facts Labels (FDA, US). Read 2026-10-23.
- Dietary Supplement Labeling Guide: Chapter IV, Nutrition Labeling (FDA, US). Dietary Supplement Labeling Guide: Chapter IV, Nutrition Labeling (FDA, US). Read 2026-10-23.
- Vitamin K (NHS, UK). Vitamin K (NHS, UK). Read 2026-10-23.
- Vitamin D (NHS, UK). Vitamin D (NHS, UK). Read 2026-10-23.
- Questions and Answers on Dietary Supplements (FDA, US). Questions and Answers on Dietary Supplements (FDA, US). Read 2026-10-23.
- Dietary Supplement Labeling Guide: Chapter VI, Claims (FDA, US). Dietary Supplement Labeling Guide: Chapter VI, Claims (FDA, US). Read 2026-10-23.
- Mixing Medications and Dietary Supplements Can Endanger Your Health (FDA, US). Mixing Medications and Dietary Supplements Can Endanger Your Health (FDA, US). Read 2026-10-23.
- Vitamins (MedlinePlus, US National Library of Medicine). Vitamins (MedlinePlus, US National Library of Medicine). Read 2026-10-23.
- Using Dietary Supplements Wisely (NCCIH, US NIH). Using Dietary Supplements Wisely (NCCIH, US NIH). Read 2026-10-23.