How to read a US dietary supplement label
Work from serving size and Daily Value to other ingredients, and understand what a label can and cannot tell you.
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Start with the product and jurisdiction
In the United States, products marketed as dietary supplements generally use a Supplement Facts panel, while conventional foods generally use Nutrition Facts. The applicable panel depends on classification and rules. Do not treat the two panels as the same system or assume a US label is automatically suitable for China.
A label is a regulated presentation of information, not a complete proof of individual suitability, therapeutic effect or actual product quality. Review the destination, final classification and requirements for the specific SKU separately.
Read a US supplement label in four steps
Confirm the basis of measurement before comparing amounts.
- Serving Size
How many capsules, scoops or grams make one serving?
- Amount Per Serving
The amount is per serving, not necessarily per container.
- % Daily Value
A labeling reference percentage, not an individual requirement percentage.
- Other Ingredients
Review excipients, carriers and relevant warnings in the full label.
This describes the US label context, not a China labeling assessment.
Begin with the serving size, not the largest number
Start with serving size and servings per container, then read the amount per serving. If a serving is two scoops but a person uses one, the per-serving numbers are not the amount in that one scoop; using two servings requires a corresponding calculation.
Check units when comparing products: 1 gram equals 1,000 milligrams and 1 milligram equals 1,000 micrograms. The weight of an ingredient complex is not necessarily the amount of a particular vitamin, mineral or other target constituent within it.
Daily Value is not an individual prescription
Percent Daily Value (%DV) shows the amount of a nutrient in a serving relative to a labeling reference value and helps compare products. It is not an individual prescription, does not mean that higher is always better, and does not replace accounting for intake from food and other supplements.
Some ingredients do not have an established Daily Value, so a %DV may not be established on the label. That does not automatically mean an ingredient is ineffective, nor does it establish a safe or effective dose. Assess the actual amount, intended use and evidence.
Proprietary blends and other ingredients
A proprietary blend may disclose the total amount of the blend without the exact amount of each ingredient. The total alone therefore cannot establish whether a particular component matches the amount used in a study; a brand name does not supply the missing number.
Also read Other Ingredients, which may include flavors, stabilizers or other excipients, and check allergen information against individual needs. An ingredient list helps describe a formula but does not independently establish finished-product quality.
Put two supplement labels on the same basis
If product A lists two capsules per serving and product B lists one, decide whether the comparison is per capsule, per serving or per day of actual use. Then compare the same nutrient amount and %DV.
For procurement, check that the label matches the specification, sample and batch documents. People taking medicines, pregnant or breastfeeding, preparing for surgery or living with illness should discuss the actual label with a clinician or pharmacist.
Review the key points
- Check serving size before comparing amounts and units.
- %DV is a labeling reference, not an individual treatment dose.
- A blend total does not reveal the amount of each component.