How to Read Supplement Labels

Every dietary supplement sold in the United States must carry a Supplement Facts panel. It is the most useful part of the package, because it tells you exactly what is in each serving. Once you know how to read it, you can compare products properly and avoid taking more than you intend.

The Supplement Facts panel, line by line

Serving size and servings per container

The serving size is the amount the manufacturer recommends taking at one time, for example one tablet or two capsules. If a serving is two capsules, a bottle of 90 lasts 45 days. Check this before comparing prices.

Amount per serving

Each nutrient is listed with its quantity. Units vary:

• mg: milligrams, a thousandth of a gram;
• mcg: micrograms, a millionth of a gram;
• IU: international units, an older measure still shown for some vitamins;
• mcg DFE, mcg RAE: units for folate and vitamin A that account for how well different forms are absorbed.

Percent Daily Value (%DV)

The %DV tells you how much one serving contributes to the recommended daily amount for adults and children aged 4 and over. The FDA gives a simple guide: 5% DV or less is low, and 20% DV or more is high. A value above 100% means the serving supplies more than the reference amount. A symbol in place of a number means no Daily Value has been set for that ingredient.

Proprietary blends

Some labels list a blend with a total weight but not the amount of each ingredient. You cannot tell how much of any one component you are getting.

Other ingredients

Below the panel is a list of non-nutrient ingredients, such as fillers, binders, colors, flavors and the capsule shell. Check this section for gelatin if you avoid animal products, and for allergens.

Other things to find on the label

• Suggested use: how and when to take the product.
• Warnings: who should not use it, and possible interactions.
• Expiration or best-by date and lot number.
• Storage instructions.
• Manufacturer or distributor name and address, required so you can contact them.

Understanding the claims

Supplements can carry three kinds of claims.

• Nutrient content claims, such as “high in vitamin C”.
• Health claims, describing a relationship between a nutrient and reduced risk of a disease, which require evidence and FDA authorization.
• Structure/function claims, such as “calcium builds strong bones”. These must be accompanied by a disclaimer that the FDA has not evaluated the statement and that the product is not intended to diagnose, treat, cure or prevent any disease.

A supplement cannot legally claim to treat or cure a disease.

Quality seals

Some products display seals from independent organizations that test supplements. The NIH notes that such seals indicate the product was properly manufactured, contains the ingredients listed and does not contain harmful levels of contaminants. They do not guarantee that a product is safe or effective.

Adding up your intake

If you take more than one supplement, add the amounts of each nutrient across all labels, and include fortified foods. Compare the total with recommended amounts and upper limits. Our Daily Multivitamin and single-nutrient products list their serving details so you can do this.

A quick label checklist

1. What is the serving size?
2. How much of each nutrient, and what %DV?
3. Any proprietary blends?
4. Any allergens or animal-derived ingredients?
5. What do the warnings say?
6. Is it in date?

The bottom line

Read the Supplement Facts panel before the marketing. Serving size, amounts and warnings tell you what you are really taking. Compare products in our vitamins and nutrition department.

Sources

1. U.S. Food and Drug Administration. Daily Value on the Nutrition and Supplement Facts Labels.
2. U.S. Food and Drug Administration. Questions and Answers on Dietary Supplements.
3. NIH Office of Dietary Supplements. Dietary Supplements: What You Need to Know.
4. U.S. Food and Drug Administration. Information for Consumers on Using Dietary Supplements.