Supplement Serving Size vs Directions: Keep the Label Fields Clear

Understand the difference between the labeled serving, units in that serving, product directions, and package serving count.

Serving size, units per serving, and package directions are related but distinct label fields. A catalog comparison should preserve each one rather than translating a bottle into a personal “days’ supply.”

Read the serving-size line

FDA’s labeling guide defines supplement serving size from the maximum amount recommended for consumption at one eating occasion on the label, or a unit when no recommendation is given. Record the printed serving, such as two capsules, and servings per container. Do not assume each capsule equals one serving.

Keep package directions separate

Copy the directions and warnings as printed, but do not convert them into a recommendation for a particular reader. For price comparison, divide the package price by labeled servings. If directions say a range or use a different period, do not use that to change the facts-panel serving count.

Frequently asked questions

Is one capsule always one serving?

No. Use the label’s serving-size line.

Can serving count tell me how many days a bottle lasts?

Not without a product-specific use pattern, and this guide does not provide one. Use labeled servings for unit-price comparison.

Sources and review

Source: FDA, Dietary Supplement Labeling Guide, Chapter IV. Reviewed September 28, 2026.

Use current SuppScan data

SuppScan presents the product data available in its catalog and does not manufacture missing values. Open the Other vitamins & minerals comparison to review current offers and normalized metrics.