How to read a supplement facts panel

Every supplement sold in the United States carries a Supplement Facts panel, and the rules for what goes on it are set by the FDA. Once you can read one, you can compare two products properly instead of comparing the front of the box.

Start at the top: serving size

On this bottle it says four capsules, and thirty servings per container. Every number below that line is per serving. This is the single most common place to be misled — not by this label, but in general. A product boasting a large number per serving may simply have a large serving.

Four capsules a day, thirty servings, is one bottle a month.

The %DV column

%DV is the percent of the Daily Value, a reference amount set for the general population. On this panel biotin shows 8333%, and selenium 364%.

A high percentage is not automatically better. It tells you the amount relative to a reference intake, nothing more. Some nutrients have an upper limit worth knowing about, which is one of the reasons the label says to consult your doctor if you take medication or have a condition.

The dagger

Two rows on this panel carry a dagger instead of a percentage, and the footnote reads "Daily Value (DV) not established." That is not a gap in the label. It means the FDA has not set a reference intake for that ingredient, so there is no percentage to give.

Other ingredients

Below the panel sits a line headed OTHER INGREDIENTS. On this bottle it lists the vegetable capsule, maltodextrin, tricalcium phosphate, silicon dioxide, organic rice hulls and pea starch. These are what hold the product together and form the capsule — they are not the actives, but they are what someone with an allergy or a dietary restriction needs to read.

The allergen line

This one matters more than any other on the pack: Contains Fish (Cod, Haddock, Pollock). The marine collagen in the formula is the reason. If you have a fish allergy, that line is the end of the conversation.

And the disclaimer

Every dietary supplement carries it: these statements have not been evaluated by the Food and Drug Administration, and the product is not intended to diagnose, treat, cure or prevent any disease. It is on this page too, for the same reason.