Quick answer
Label claim is the amount of an ingredient a label says each serving contains. Lab results are often given as a percentage of it. Under FDA rules, an added vitamin or mineral must be present at no less than 100% of the label claim, and a naturally occurring one at no less than 80% (21 CFR 101.9(g)).1,2
Key facts
- FDA's labeling rule for supplements applies these tests to other dietary ingredients too, not only vitamins and minerals.2
- Compliance is judged on a composite of 12 packages, or 10% of the packages in the lot if that is fewer, chosen at random.2
- FDA accepts reasonable excesses over labeled amounts within current good manufacturing practice.1,2
- For calories, sugars, fat and sodium the rule runs the other way: a product fails if it has more than 120% of the label value.1
Two meanings of label claim
On a lab report, label claim means the declared amount per serving, the number printed in the Supplement Facts panel. People also use the phrase for statements on a label about what a product does, which FDA groups as structure/function, health and nutrient content claims.3
For minerals, the label claim is the weight of the mineral itself, not of the compound that supplies it: calcium rather than calcium carbonate.2
Percent of label claim
Percent of label claim is the measured amount divided by the declared amount, times 100. A capsule labeled 500 mg that measures 520 mg is at 104%.4
| Type of ingredient | Lowest acceptable result | Highest acceptable result |
|---|---|---|
| Added vitamin, mineral, protein or fiber (Class I) | 100% of label | Reasonable excess within good manufacturing practice |
| Naturally occurring nutrient (Class II) | 80% of label | Reasonable excess within good manufacturing practice |
| Calories, sugars, total fat, saturated fat, sodium | Reasonable shortfall within good manufacturing practice | 120% of label |
For a naturally occurring nutrient, FDA will not act on a shortfall smaller than the normal variability of the test method.1
How far real products stray
Surveys show the spread. In about 30 melatonin products, measured content ranged from 83% below to 478% above label claim, more than 71% fell outside a 10% margin, and one product varied by up to 465% from lot to lot.4
Going over is common. National data on adult multivitamins found the measured amount of every nutrient but thiamin averaging above its declared amount, a result of extra added to cover losses in storage.5
Proprietary blends leave a gap. The label gives one total weight for the blend's other dietary ingredients, so there is no individual label claim for each of them to test against.2
Questions people ask
Is 110% of label claim a problem?
Not necessarily. FDA's labeling rule accepts reasonable excesses within good manufacturing practice, and makers often add extra to cover losses over shelf life, which is called an overage.2,5
Why might a product test below its label claim?
Ingredients can break down over time, especially with heat and moisture, or a product can be made with too little. For an added nutrient, a result below the declared amount makes the product misbranded under FDA's rule.1,6
What is the percent label claim formula?
Measured amount divided by label amount, times 100. Use the same units and the same basis, such as per capsule or per serving, for both numbers.4
See what we make
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Sources
- 21 CFR 101.9(g). Nutrition labeling of food: how compliance is determined. Opened 2026-10-07.
- 21 CFR 101.36. Nutrition labeling of dietary supplements. 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.
- Erland LA, Saxena PK. Melatonin natural health products and supplements: presence of serotonin and significant variability of melatonin content. J Clin Sleep Med. 2017;13(2):275-281. Opened 2026-10-07.
- Andrews KW, Roseland JM, Gusev PA, et al. Analytical ingredient content and variability of adult multivitamin/mineral products: national estimates for the Dietary Supplement Ingredient Database. Am J Clin Nutr. 2017;105(2):526-539. Opened 2026-10-07.
- Giménez R, Cabrera C, Olalla M, Ruiz MD, López MC. Ascorbic acid in diet supplements: loss in the manufacturing process and storage. Int J Food Sci Nutr. 2002;53(6):509-518. Opened 2026-10-07.
This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.