Supplement Serving Size Explained
Why “per serving” can mean one capsule or five, and how that changes comparisons.
On a Supplement Facts panel, every amount is per serving, and the manufacturer chooses what a serving is. Always check how many capsules, gummies or scoops make one serving before comparing amounts or prices.
- Serving size is set by the manufacturer.
- Compare amounts per serving and units per serving together.
- Servings per container, not units per container, determines how long a bottle lasts at label use.
What a serving is
The serving size is the amount the label recommends taking at one time, stated in units (capsules, softgels, gummies) or by weight/scoop for powders. All amounts on the panel refer to that serving.
Why it matters for comparisons
A “200 mg magnesium” product at 4 capsules per serving delivers 50 mg per capsule; another at 2 capsules delivers 100 mg per capsule. Gummies often split a normal amount across several pieces — for example 5 g creatine across four or five gummies.
Units to watch
- mg (milligrams) and g (grams): 1 g = 1,000 mg
- mcg (micrograms): 1 mg = 1,000 mcg
- Vitamin D: 1 mcg = 40 IU
- Folate: mcg DFE (dietary folate equivalents)
Sources & references
- 21 CFR 101.36 — Nutrition labeling of dietary supplements. Electronic Code of Federal Regulations. ecfr.govRegulatory
- Dietary Supplement Labeling Guide. U.S. Food and Drug Administration. fda.govRegulatory
SuppScout links to primary and authoritative sources wherever possible. See our editorial policy for how sources are selected and how corrections are handled.
This page is educational and is not medical advice. Talk to a healthcare professional before starting a supplement, especially if you have a medical condition, take medications, or are pregnant or breastfeeding.