How to Read a Supplement Facts Label

A bottle of vitamins or an herbal capsule does not carry a Nutrition Facts label. It carries a Supplement Facts panel, which follows its own federal rule, 21 CFR 101.36. The layout looks familiar, but several parts work differently: what is listed, how amounts are shown, and what a small dagger symbol means. Here is how to read one, using the regulation and guidance from FDA and the NIH Office of Dietary Supplements (ODS).

1. What must be on a supplement label

FDA's questions-and-answers page on dietary supplements lists the required label elements:

• The product name and the words "dietary supplement," or an equivalent such as "iron supplement" or "herbal supplement"
• The name and place of business of the manufacturer, packer, or distributor
• The Supplement Facts panel (with limited exceptions for some small-volume products or eligible small businesses)
• A list of "Other ingredients" not declared in the panel
• The net quantity of contents
• A domestic address or phone number for reporting serious adverse events

2. Reading the panel, top to bottom

2.1. Serving size

Under 21 CFR 101.36, "Serving Size" sits right under the "Supplement Facts" heading and uses a unit that fits the form, such as tablets, capsules, packets, or teaspoonfuls. "Servings Per Container" follows below it.

FDA adds a point many people miss: no law limits the serving size of a supplement or the amount of an ingredient in a serving. The manufacturer decides. ODS notes that the manufacturer suggests the serving size, but your health care provider might decide a different amount is better for you.

2.2. Amount Per Serving and %DV

Ingredients that have an established Daily Value, such as vitamins and minerals, are listed with an amount by weight and a % Daily Value. The regulation sets a fixed order for vitamins and minerals, beginning with vitamin A, vitamin C, vitamin D, vitamin E, and vitamin K.

The %DV is calculated by dividing the amount per serving by the Daily Value and multiplying by 100. For example, the Daily Value for magnesium for adults is 420 mg. A tablet with 100 mg of magnesium provides 100 ÷ 420 × 100 = 23.8%, which is shown as 24%, because 21 CFR 101.36 rounds supplement %DV to the nearest whole percent (as of October 2026).

The regulation also allows the source to be named in parentheses, as in "Calcium (as calcium carbonate)." When the source is named there, it does not have to be repeated in the ingredient list.

2.3. The symbol: "Daily Value not established"

Ingredients without a Daily Value, such as many herbs, amino acids, or other compounds, are still listed with an amount per serving. In the %DV column they get a symbol, such as an asterisk or a dagger (†), that points to a footnote reading "Daily Value not established." It does not mean the ingredient is unsafe or ineffective. It means FDA has no reference amount to compare it with.

3. Proprietary blends

A proprietary blend is a group of ingredients listed under a name such as "Proprietary Blend" or a branded name. The rules in 21 CFR 101.36(c):

• Ingredients without a Daily Value inside the blend are listed in descending order by weight.
• The amount shown is the total weight of those ingredients together, not each one.

So a blend label tells you which ingredient is most plentiful, but not how much of each one you are getting. FDA's Q&A confirms that dietary ingredients in a proprietary blend are the exception to the rule of listing the amount of each ingredient per serving.

4. Other ingredients

Anything not in the panel must appear in the "Other ingredients" list below it. FDA gives examples: the source of a dietary ingredient if not shown in the panel (such as rose hips as the source of vitamin C), water, sugar, food additives, color additives, gelatin, starch, stabilizers, preservatives, and flavors. ODS describes these as ingredients such as fillers, binders, and flavorings.

5. The FDA disclaimer

If a label makes a structure/function claim, such as a statement about how an ingredient supports a body function, it must carry this disclaimer under 21 CFR 101.93:

This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

FDA explains why: these claims are not approved by FDA and do not need FDA evaluation before use, and only a drug can legally claim to diagnose, treat, cure, or prevent a disease.

6. What the label cannot tell you

FDA states that, under the law, it does not approve dietary supplements before they are marketed, and that it does not test supplements before they are sold. ODS adds that FDA does not determine whether supplements are effective before they reach the market. The label tells you what the manufacturer says is in the product, not that it works.

ODS's advice is to talk with your health care providers before taking supplements, especially in place of or alongside prescribed medicines.

7. Key takeaways

• Supplements use a Supplement Facts panel under 21 CFR 101.36, not a Nutrition Facts label.
• The manufacturer sets the serving size; no law limits it.
• A symbol with "Daily Value not established" means there is no reference amount, not that the ingredient is unsafe.
• A proprietary blend shows the blend's total weight and the order of ingredients, not each amount.
• The FDA disclaimer appears with structure/function claims; FDA does not approve supplements before sale.