To read a Supplement Facts label, start with the serving size, because every amount underneath it refers to one serving. Then check each ingredient's amount per serving and the form or plant part it comes from, look at the %DV column, and finish with the "Other Ingredients" line just below the box.
That's the short version. Below we walk through each line using the federal rule that governs the panel, 21 CFR 101.36. Then we read a real label from our own range, OPA Resveratrol 600 mg, line by line.
Last reviewed: October 20, 2026.
Key Takeaways
- Dietary supplements sold in the US have to carry a Supplement Facts panel under federal rule 21 CFR 101.36, apart from a few small-business and low-volume exemptions.
- Amounts are per serving, and a serving can be more than one capsule. Check the serving size before you compare two bottles.
- For vitamins and minerals, the amount shown is the nutrient itself: the weight of the calcium, not the calcium carbonate it comes from.
- Herbal ingredients have to name the part of the plant used, such as root or leaf.
- A symbol in the %DV column that points to "Daily Value not established" means the FDA has no daily target for that ingredient. It doesn't mean the amount is high or low.
- The panel can't tell you whether a product works or whether it's right for you. The FDA doesn't approve supplements before they're sold.
What is a Supplement Facts label?
A Supplement Facts label is the boxed panel that federal rules require on dietary supplements sold in the United States. The rule, 21 CFR 101.36, sets what goes in the box, the order it goes in, and even the type size and the lines between rows.
The point is to make labels comparable. It doesn't mean anyone checked the product first. The FDA says it doesn't have the authority to approve dietary supplements before they're marketed. According to the NIH Office of Dietary Supplements (ODS), the company is responsible for having evidence that its products are safe and that its label claims are truthful and not misleading.
How is Supplement Facts different from Nutrition Facts?
The Supplement Facts panel looks a lot like the Nutrition Facts box on food, but the FDA's Dietary Supplement Labeling Guide lists four differences that matter when you're reading one.
| What the rule covers | Supplement Facts | Nutrition Facts (food) |
|---|---|---|
| Ingredients with no Daily Value, such as herbs and extracts | Must be listed, with amounts | Not allowed in the panel |
| The source of a nutrient, as in "Calcium (as calcium carbonate)" | May be listed in the panel | Not allowed in the panel |
| The part of the plant an ingredient comes from | Must be listed | Not allowed in the panel |
| Nutrients present at zero | Not allowed to be listed | Must be listed |
That's why a supplement panel can list an herbal extract by weight with no percentage next to it, while a cereal box can't list an herb in its panel at all.
How do you read a Supplement Facts label, step by step?
Read it from the top down. Each step below matches a part of the panel that 21 CFR 101.36 requires.
- Serving size. It sits right under the title, written in units that fit the product: capsules, tablets, packets or teaspoonfuls. Every amount below refers to this serving. If the serving is 2 capsules, the milligrams shown are for both capsules together.
- Servings per container. This comes next, unless it's already given in the package's net quantity statement. Multiply servings by the serving size and you get the number of capsules in the bottle.
- Amount per serving. Each dietary ingredient is listed with its weight per serving. For vitamins and minerals, that's the weight of the nutrient itself; the rule's own example is the weight of calcium rather than calcium carbonate. For a dried herbal extract, it's the weight of the dried extract.
- Form and source. A brand can name the source in parentheses with "as" or "from," such as "Calcium (as calcium carbonate)." Herbal ingredients must also name the part of the plant they come from.
- % Daily Value. For nutrients that have an FDA Daily Value, this column shows how much of it one serving supplies. Everything else gets a symbol that points to a footnote reading "Daily Value not established."
- Other ingredients. The ingredient statement sits below the box, or right beside it if space is tight. ODS describes this as where you'll find fillers, binders and flavorings.
One more thing the rule allows: when a label tells you to take more than one serving a day, the brand may add a "Per Day" column next to the per-serving amounts. It's optional, so don't count on seeing it.
How do you read a real label? The OPA Resveratrol 600 mg panel, line by line
Here's the Supplement Facts panel from OPA Resveratrol 600 mg, exactly as it's printed on the label and shown on the product page. We picked it because it's short: one active ingredient, one footnote and two other ingredients.
Here are the same lines typed out exactly as printed, one at a time, with what each one tells you:
| Line on the label | What it tells you |
|---|---|
| Serving Size: 1 Capsule | Every amount below is for one capsule. |
| Servings Per Container: 30 | 30 servings of 1 capsule each, so 30 capsules in the bottle. |
| Resveratrol (Polygonum cuspidatum)(root) 600mg | The ingredient, the plant species and the plant part, which the rule requires for botanicals. The 600 mg is the weight of the resveratrol complex, the extract, in one capsule. |
| (Complex Containing 50% Trans- Resveratrol) | The extract is standardized: half of it is trans-resveratrol. So one capsule supplies about 300 mg of trans-resveratrol (600 mg × 50%). |
| ** in the %DV column | Points to the footnote "Daily Value (DV) not established." The FDA hasn't set a Daily Value for resveratrol, so there's no percentage to show. |
| Other Ingredients: Vegetable Capsule (Cellulose), Microcrystalline Cellulose | The non-active ingredients: the capsule shell, made from cellulose, and microcrystalline cellulose. |
What the panel doesn't cover is just as useful to know. It doesn't say how many capsules to take a day; that's in the suggested use printed elsewhere on the label. And it can't tell you how much resveratrol your body actually absorbs. Our resveratrol guide covers what the studies show.
OPA Resveratrol 600 mg (30 veggie capsules): 600 mg of Polygonum cuspidatum root extract standardized to 50% trans-resveratrol, about 300 mg of trans-resveratrol per capsule, for antioxidant support.
What does %DV mean, and what counts as high?
%DV is the share of a nutrient's Daily Value that one serving provides. The FDA's general guide is that 5% DV or less per serving is low and 20% DV or more is high. The agency wrote that guide for food labels, but the Daily Values themselves are the same ones used on Supplement Facts panels.
Supplements often go well past 100%. The FDA's Daily Value for vitamin D is 20 mcg, so a softgel with 50 mcg (2,000 IU) shows 250% DV.
That isn't automatically a problem, but it helps to know the ceiling. ODS puts the upper limit for vitamin D at 100 mcg (4,000 IU) a day for adults 19 and older, counting food, drinks and supplements together. If you take more than one product, add up the amounts across all of them.
What does "Daily Value not established" mean?
"Daily Value not established" means the FDA hasn't set a Daily Value for that ingredient, so there's no percentage to calculate. Under 21 CFR 101.36, ingredients without one, such as most herbs and extracts, carry a symbol in the %DV column that points to that footnote.
It isn't a warning, and it doesn't mean the amount is unusual. It just means %DV can't help you judge that ingredient. To put the milligrams in context, you need the research on that specific ingredient and the form used.
What is a proprietary blend on a supplement label?
A proprietary blend is a group of ingredients listed under one name with one total weight. Under 21 CFR 101.36(c), the ingredients inside it are listed in descending order by weight, and the amount shown is the total for the blend. The rule doesn't require the amount of each ingredient.
That makes it hard to compare a blend with a studied amount of any one ingredient. We go into what to do about that in our no-hype guide to longevity supplements.
What isn't on a Supplement Facts label?
The panel describes what's in one serving. A few things people look for aren't part of it:
- Nutrients at zero. Supplement labels aren't allowed to list nutrients that are present at zero. A missing line just means none.
- How much to take each day. That's the suggested use, printed elsewhere on the label. The "Per Day" column is optional.
- The amount of each ingredient in a blend. Only the blend's total weight is required.
- Proof that it works. Claims about what a product does appear elsewhere on the label. When a label says how a supplement affects the body's structure or function, 21 CFR 101.93 requires the standard FDA disclaimer next to it or linked by an asterisk.
Where else on the bottle should you look?
The rest of the label fills in what the panel leaves out. Here's what to check.
| Part of the label | What to look for |
|---|---|
| Front of the package | The words "dietary supplement," or an equivalent such as "herbal supplement," which the FDA requires. |
| Claims with an asterisk | Any statement about what the product supports should point to the FDA disclaimer. |
| Suggested use | How many servings to take, how often, and whether to take them with food. |
| Cautions | Who should check with a healthcare provider before using the product. |
| Company contact details | ODS advises reporting any reaction to the manufacturer, using the contact information on the label, as well as to the FDA. |
For the bigger picture on choosing a product, including what independent testing seals do and don't tell you, see our longevity supplements guide. For why "healthy aging" has become the goal in the first place, read healthspan vs lifespan.
Frequently asked questions
How do you read supplement facts?
Start with the serving size, since every amount refers to one serving. Then read each ingredient's amount per serving and its source or plant part, check the %DV column, and finish with the "Other Ingredients" list just below the panel.
What's the difference between Supplement Facts and Nutrition Facts?
Supplement Facts panels must list ingredients that have no Daily Value, such as herbs, and must name the plant part. They may name the source of a nutrient, and they can't list nutrients present at zero. Nutrition Facts panels on food work the other way on all four points.
What %DV is considered high?
The FDA's general guide is that 20% DV or more per serving is high and 5% DV or less is low. Supplements often exceed 100% DV, so it's worth checking the upper limit for nutrients such as vitamin D.
What is not required on the Supplement Facts label?
The individual amounts inside a proprietary blend, a "Per Day" column, and servings per container when it's already given in the package's net quantity statement. Nutrients at zero aren't listed at all. Suggested use appears elsewhere on the label, not in the panel.
Why does my supplement say "Daily Value not established"?
Because the FDA hasn't set a Daily Value for that ingredient. That's normal for herbs, extracts and compounds such as resveratrol. It isn't a warning; it just means there's no percentage to show.
How can I tell if a supplement is high quality?
The label alone can't prove it. The FDA requires companies to follow Good Manufacturing Practices meant to help ensure identity, purity, strength and composition. Beyond that, look for a clear, fully disclosed label and ask the company how it tests finished products.
Sources
- Electronic Code of Federal Regulations. 21 CFR 101.36: Nutrition labeling of dietary supplements. Accessed October 20, 2026.
- Electronic Code of Federal Regulations. 21 CFR 101.93: Certain types of statements for dietary supplements. Accessed October 20, 2026.
- US Food and Drug Administration. Dietary Supplement Labeling Guide: Chapter IV. Nutrition Labeling. April 2005.
- US Food and Drug Administration. Daily Value on the Nutrition and Supplement Facts Labels. Content current as of March 5, 2024.
- US Food and Drug Administration. How to Understand and Use the Nutrition Facts Label. Accessed October 20, 2026.
- US Food and Drug Administration. Questions and Answers on Dietary Supplements. Accessed October 20, 2026.
- NIH Office of Dietary Supplements. Dietary Supplements: What You Need to Know. Accessed October 20, 2026.
- NIH Office of Dietary Supplements. Vitamin D: Fact Sheet for Consumers. Updated November 8, 2022.
Disclosure: OPA Nutrition sells supplements, including products mentioned in this article. This content is for education only and is not medical advice. Statements about dietary supplements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease. Talk to your healthcare provider before using any supplement, especially if you take medication or have a medical condition.
