PlainVitamins

Guide

Comparing two supplements with data

Two labels can print the same number and mean different things, or different numbers and mean the same. Five checks make a comparison fair, and PlainVitamins does most of them for you.

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Written with AI tools under the editorial policy. Every figure is read from the label database, not written by the model.

1. Compare in the same measure

Milligrams compare with milligrams. Vitamin D converts exactly between IU and micrograms (40 IU per microgram), but vitamin A in IU and in micrograms RAE, folate as micrograms or micrograms DFE, and vitamin E in IU depend on the form, so they compare only within one unit. PlainVitamins compares each amount only with amounts in the same measure and says how many products that is.

2. Check what a serving is

The panel is per serving, and servings differ: two gummies, one tablet, a scoop. Forms differ systematically too. Across the database, a vitamin C gummy serving lists a median of 45 mg, a tablet serving 120 mg. Amounts by physical form has ten nutrients.

Figures: NIH ODS Dietary Supplement Label Database, version 9.4.0, current labels.

3. Compare per day, not per bottle

A product taken three times a day gives three times its panel. Where a label's directions give a number of servings a day, its PlainVitamins page shows the amount per day at the most servings allowed beside the amount per serving. Price per serving or per bottle is not in the label data; work it out from the servings per container.

4. Look at the form

Magnesium oxide and magnesium glycinate, cyanocobalamin and methylcobalamin: the same nutrient in different compounds. The label weight of a mineral is the element itself, but the form can matter for other reasons, which the NIH fact sheets discuss. Each form named on enough labels has its own page, for example magnesium glycinate.

5. Mind what is not disclosed

A row inside a proprietary blend has no amount of its own, so it cannot be compared; 29% of products have at least one. Two blend products can list the same ingredients and contain very different amounts of each.

Figures: NIH ODS Dietary Supplement Label Database, version 9.4.0, current labels.

The closest formulas, found for you

Every product page lists up to six products with the closest formula: the most ingredients in common, rare ones counting for more, at the nearest amounts. Sometimes the match is exact: 2,044 formulas of four or more ingredients appear amount for amount under two or more brand names, covering 6,154 products (one formula, many brands). To put any two products side by side, use compare.

Figures: NIH ODS Dietary Supplement Label Database, version 9.4.0, current labels.

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