Quick answer
On a supplement, the serving size is the most the label recommends taking at one time, or 1 unit, such as a tablet or capsule, when the label gives no directions. If the directions say 1 to 3 tablets with breakfast, the serving size is 3 tablets, and every amount on the panel is per serving.1,2
Key facts
- The panel must use the words Serving Size, in a unit that suits the product: tablets, capsules, packets or teaspoonfuls.2,3
- No law caps the size of a supplement serving or the amount of an ingredient in it; the manufacturer decides, and FDA approval is not needed.4
- Servings Per Container goes under the serving size, unless the net quantity already gives the count, as with 100 tablets and a 1 tablet serving.2,3
- A label that recommends more than one serving a day may add a per day column beside the per serving figures.3
- NIH notes that the manufacturer suggests the serving size, but a health care provider may decide a different amount suits you better.5
How the serving size is set
FDA rules define a supplement serving as the maximum amount the label recommends for one eating occasion. When the label recommends no amount, a serving is 1 unit. The rule looks at a single occasion, not the whole day, so a product taken as 2 capsules twice a day has a serving size of 2 capsules.1,2
The heading over the amounts can follow the serving. Amount Per Serving, Each Tablet Contains and Amount Per 2 Tablets are all allowed, as are terms such as capsule, packet or teaspoonful.2,3
Serving size, servings per container and the daily amount
| Figure | What it tells you | Where it appears |
|---|---|---|
| Serving size | The amount every figure on the panel is based on | Top of the Supplement Facts panel |
| Servings per container | How many servings the package holds | Under the serving size, unless the net quantity already says it |
| Per day amount | The total for all the servings the label recommends in a day | An optional extra column, or a short note after the serving size |
Because each amount and % Daily Value is per serving, a label that recommends two servings a day delivers twice what each line shows, unless it adds a per day column.3
Serving size and the % Daily Value
The % Daily Value on each line compares one serving with a reference amount for a whole day. FDA's own example is a supplement serving with 25 mcg of vitamin D, which lists 125% of the 20 mcg Daily Value. Two such servings would supply 50 mcg.6,7
A maker may also add a column of amounts per unit, such as per tablet, to the right of the per serving column, as long as it is clearly headed.3
Before taking more than one serving
FDA advises talking to a doctor, pharmacist or other health care professional before using a supplement, in part because some supplements interact with medicines or other supplements. That matters most when you plan to take more than the label's serving.4
Questions people ask
Is the serving size the dose I should take?
It is the label's own direction for one occasion, not a dose set by the FDA. The agency does not limit serving sizes, and NIH notes your health care provider may suggest a different amount.4,5
Why is the serving size 2 capsules if the label says to take 4 a day?
The serving size is the most the label recommends for one occasion. If the directions say 2 capsules twice a day, the serving is 2 capsules, and each figure on the panel is half the daily total unless a per day column is added.1,3
Can a product show amounts per tablet as well as per serving?
Yes. A per unit column may be added to the right of the per serving column, with a clear heading.3
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Sources
- Code of Federal Regulations, Title 21, Section 101.12: Reference amounts customarily consumed per eating occasion. Legal Information Institute, Cornell Law School (eCFR text). Opened 2026-10-07.
- U.S. Food and Drug Administration. Dietary Supplement Labeling Guide: Chapter IV. Nutrition Labeling. April 2005. Opened 2026-10-07.
- Code of Federal Regulations, Title 21, Section 101.36: Nutrition labeling of dietary supplements. Legal Information Institute, Cornell Law School (eCFR text). Opened 2026-10-07.
- U.S. Food and Drug Administration. Questions and Answers on Dietary Supplements. Content current as of August 27, 2026. Opened 2026-10-07.
- NIH Office of Dietary Supplements. Dietary Supplements: What You Need to Know. Fact Sheet for Consumers. Updated January 4, 2023. Opened 2026-10-07.
- U.S. 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. Opened 2026-10-07.
- U.S. Food and Drug Administration. Daily Value on the Nutrition and Supplement Facts Labels. Content current as of March 5, 2024. Opened 2026-10-07.
This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.