Quick answer: Start with the serving size, then read the amount and form of each ingredient and its % Daily Value, then the other ingredients and allergen statement. Check the lot number, best-by date and manufacturer contact details, and remember that a structure/function claim comes with an FDA disclaimer because the FDA has not evaluated it.
Last updated: November 10, 2026
Every dietary supplement sold in the U.S. carries a Supplement Facts panel, the supplement version of the Nutrition Facts label on foods. FDA rules (21 CFR 101.36) set what it must show. Here is how to read it, from top to bottom.
An example panel
| Supplement Facts | Amount per serving | % Daily Value |
|---|---|---|
| Serving size: 2 capsules · Servings per container: 30 | ||
| Vitamin D (as cholecalciferol) | 25 mcg (1,000 IU) | 125% |
| Magnesium (as magnesium glycinate) | 120 mg | 29% |
| Turmeric root extract (Curcuma longa) (standardized to 95% curcuminoids) | 250 mg | † |
| † Daily Value not established. | ||
| Other ingredients: hypromellose (capsule), rice flour, magnesium stearate. | ||
This is an illustration, not a real product.
1. Serving size and servings per container
Every number on the panel refers to one serving, which may be more than one capsule, tablet, gummy or scoop. If the serving is 2 capsules and you take 1, you get half the listed amounts.
2. Amount per serving and units
Amounts are listed in standard units: grams (g), milligrams (mg) or micrograms (mcg). Some nutrients use special units: vitamin A in mcg RAE, folate in mcg DFE, niacin in mg NE and vitamin E in mg of alpha-tocopherol. Vitamin D is listed in mcg, often with IU in parentheses; 1 mcg of vitamin D equals 40 IU.
3. % Daily Value
The % Daily Value (%DV) shows how much one serving contributes to the Daily Value, a reference amount set by the FDA for labeling. More than 100% is common in supplements and isn't automatically a problem, but it is a reason to check the Tolerable Upper Intake Level and add up other sources. A symbol, often †, next to an ingredient means "Daily Value not established," as with most herbs and specialty ingredients.
4. Nutrient forms
The words in parentheses tell you the form: "Magnesium (as magnesium glycinate)" or "Vitamin B12 (as methylcobalamin)." For minerals, the amount listed is the mineral itself (elemental), not the whole compound. Forms can differ in how much nutrient they provide and how they sit with your stomach.
5. Botanicals and extracts
Herbal ingredients should list the common name, often the Latin name, and the plant part used, such as root, leaf or berry. An extract may say it is standardized to a percentage of a marker compound.
6. Proprietary blends
A proprietary blend lists the ingredients in the blend in descending order by weight, but only the total weight of the blend is required, not the amount of each ingredient. That makes it harder to compare products or know how much of one ingredient you are getting.
7. Other ingredients
Below the panel, "Other ingredients" lists everything else, such as the capsule shell, fillers, flow agents, sweeteners, flavors and colors, in descending order of predominance by weight. Gelatin capsules come from animals; hypromellose capsules are plant-based.
8. Allergen statement
Supplements must declare the major food allergens they contain: milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, soybeans and sesame. Fish oil, krill oil, whey protein and some probiotics are common examples where this matters.
9. Directions and warnings
Follow the directions for how much and when to take the product. Warnings matter too: products containing iron must carry this statement under 21 CFR 101.17(e): "WARNING: Accidental overdose of iron-containing products is a leading cause of fatal poisoning in children under 6. Keep this product out of reach of children. In case of accidental overdose, call a doctor or poison control center immediately."
10. Lot number and dates
The lot number identifies the production batch, which helps with questions or recalls. Expiration or "best by" dates aren't required for supplements, but when a company uses one, it should have data to support it. Use the product before the date and store it as directed.
11. Claims and the FDA disclaimer
Supplements may make structure/function statements that describe how a nutrient affects the body, such as "calcium helps support healthy bones." When they do, the label must carry this disclaimer, often marked with a symbol such as † or *:
These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.
It means the FDA has not reviewed the statement. Supplements are not allowed to make disease claims, so be cautious of any label that promises to fix a health condition.
12. Manufacturer details and seals
The label must include the name and place of business of the manufacturer, packer or distributor, plus a U.S. address or phone number for reporting problems. Independent seals such as USP Verified or NSF Certified for Sport show that a specific product met that program's standard; read What USP, NSF and other seals really mean for what they do and don't cover.
Put it into practice
Compare two products by the amount and form per serving, not by the front of the box. Look up any unfamiliar term in our Vitamin & Supplement Glossary. Read Supplement safety before starting something new, and see how these labels apply in Vitamins, Minerals, Herbs & Botanicals and Omega-3 & Fish Oil, or in our guide Vitamin D in winter.
Talk to your doctor or pharmacist before starting a supplement, especially if you're pregnant or nursing, take medication, or have a medical condition.
†These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.
Sources
- FDA: Dietary Supplement Labeling Guide
- eCFR: 21 CFR 101.36, Nutrition labeling of dietary supplements
- eCFR: 21 CFR 101.17, Food labeling warning statements (including iron)
- FDA: Daily Value on the Nutrition and Supplement Facts Labels
- FDA: Food Allergies
- NIH Office of Dietary Supplements: Dietary Supplements, What You Need to Know
- FDA: Information for Consumers on Using Dietary Supplements