How to read a Supplement Facts label

Read a Supplement Facts label from the top down: serving size, servings per container, then the amount of each ingredient per serving, then the % Daily Value column, and finally the "Other Ingredients" line underneath. Compare two products only after you convert both to the same serving. Most label mistakes come from skipping the first two lines.

This guide follows the FDA's own labeling rules, so you can check a bottle in your hand or the label image on a sales page in about two minutes.

What is on a Supplement Facts panel?

By FDA rules, the panel must list the serving size, the number of servings per container, and the name and quantity of each dietary ingredient in the product. The FDA's labeling guide adds one exception: "servings per container" can be left off when it matches the net quantity statement, for example a bottle of 100 tablets with a serving size of one tablet.

Below the panel comes a separate line, headed "Other Ingredients" when some ingredients are already named inside the panel. The label must also carry a domestic address or phone number where serious adverse events can be reported, according to the FDA's Q&A on dietary supplements.

One thing the panel is not: an approval. The FDA says it does not have the authority to approve dietary supplements before they are marketed, and it generally does not approve label claims before use. A tidy panel tells you what the seller declares, nothing more.

How do you read the serving size and servings per container?

Start here, because every other number on the panel is "per serving." The FDA guide defines one serving as the maximum amount the label recommends per eating occasion, or one unit (a tablet, capsule, packet or teaspoon) if there is no recommendation. Its own example: if the directions say to take 1-3 tablets with breakfast, the serving size is 3 tablets.

This matters because the serving is not always one pill. If a panel says "Serving Size: 2 capsules" and "Servings Per Container: 30," the bottle holds 60 capsules and lasts 30 days at a once-a-day dose. Sales pages sometimes quote the per-capsule price or the per-capsule amount, so check that the number you are comparing matches the serving on the panel.

Also check the directions. A panel built on 2 capsules a day may sit next to a bottle that says "take up to 4 a day." The amounts on the panel then cover only half of the top dose.

What does "Amount Per Serving" tell you?

This column is the point of the whole panel. The FDA requires the quantity by weight of each dietary ingredient per serving (mg, mcg or g), with one exception covered below: proprietary blends. For vitamin D, the amount must be in mcg, and IU may follow in parentheses.

Look at three things in this column:

• The form. "Calcium (as calcium carbonate)" tells you the source. The FDA guide notes that source ingredients can be named inside the panel this way.
• The unit. mg and mcg differ by a factor of 1,000. Misreading one for the other is a common arithmetic slip.
• The extract, if any. A liquid extract must be listed by the volume or weight of the total extract. A bare plant name with a big weight does not say how much of the active part you get.

What does the % Daily Value column mean?

The % DV is the share of a Daily Value that one serving supplies. The FDA guide gives the formula and an example: 60 mg of vitamin C is 100% of the Daily Value for vitamin C. It is listed for ingredients that have an established Daily Value, such as vitamin C, vitamin D, calcium and iron.

The FDA's general guide on the Nutrition Facts label says 5% DV or less per serving is low and 20% DV or more is high. That guide is written for foods, so treat it as a rough yardstick, not a dosing target. A higher %DV is not automatically better, and a doctor or pharmacist can tell you what fits your situation.

Ingredients without a Daily Value, such as most herbs and amino acids, get a symbol in that column that points to the footnote "Daily Value Not Established" (the FDA guide describes this). Do not read that as a bad sign. It only means there is no benchmark to compare against.

What does a missing amount mean?

Under the FDA rule as the guide describes it, an ingredient in the panel must come with its weight per serving unless it sits inside a proprietary blend. So a missing amount usually means one of three things:

1. The ingredient is inside a blend, and only the blend has a total weight.
2. You are looking at a sales-page ingredient list, not the real panel. A page can name nine ingredients and never show a Supplement Facts panel at all.
3. The label is not following the rules. That is a question for the seller, and for the FDA if it is a real bottle.

The first case is common. For example, our ProDentim review notes that the total of 3.5 billion is given, while the split between strains is not. Our Gluco6 review shows the opposite mix: exact amounts for vitamin D3, vitamin B1 and chromium, and seven plant and stimulant ingredients sharing a single 525 mg total. Both are labeling choices you can only spot by reading the amount column, which is why we check it first in every review. Blends get their own section in our next guide on the DoseAudit blog.

What is in the "Other Ingredients" line?

These are the ingredients that are not dietary ingredients: binders, colors, fillers, flavors, sweeteners and other excipients, according to the FDA guide. The line must sit immediately below the panel, and the ingredients must be listed in descending order of predominance by weight. The first item weighs the most, the last weighs the least.

That order is a useful clue. If a filler is listed first, it outweighs everything after it. Also scan this line for anything you avoid, such as an allergen or a sweetener. The FDA Q&A states that ingredients not listed in the panel must appear in "Other Ingredients."

How do you compare two labels side by side?

Put both on the same footing before you look at price. Here is a made-up example to show the method:

Bottle A looks twice as strong per serving, but per capsule the two are identical, and Bottle B costs half as much per serving because it uses one capsule instead of two. That is why the amount per serving, the serving size and the real price of the bundle you are buying belong in the same calculation. Our how we review page explains how we do the same with the actual checkout price.

What is a quick checklist for any label?

1. Is there a real Supplement Facts panel, or only a list of names?
2. What is the serving size, and does it match the directions?
3. How many servings are in the container, and what is the price per serving?
4. Does every ingredient have an amount in mg, mcg or g, or does it sit in a blend?
5. Is the form named (for example "as calcium carbonate" or a specific probiotic strain)?
6. What is the % DV, and is there a Daily Value at all?
7. What is in "Other Ingredients," and is there anything you avoid?
8. Is there a company name and a way to reach it?

If you take prescription medicine, are pregnant, or are planning surgery, show the label to your doctor or pharmacist before you start. The NIH's NCCIH page on using dietary supplements wisely says to tell your health care providers about all supplements you take. You can browse our blood sugar reviews or all reviews to see how each panel is broken down.

FAQ

Is the serving size the same as the recommended dose?

Usually it matches the directions, since the FDA guide defines a serving as the maximum amount the label recommends per eating occasion. Still, read the directions: some labels say to take the serving more than once a day.

What does "Daily Value not established" mean?

It means there is no Daily Value to compare the ingredient with, so no % DV is given. The amount in mg or mcg is still listed unless the ingredient is inside a blend.

Are the ingredients on a sales page the same as the label?

Not necessarily. The panel on the bottle is the label. A sales page can show a different list, a photo of an older label, or no panel at all. Ask the seller for a clear image of the current panel before you pay.

Does a complete Supplement Facts panel mean the product is safe or effective?

No. The panel describes what the seller says is in the product. The FDA does not approve supplements before they are sold, and NCCIH notes that what is on the label may not always be what is in the product.