How to Read a Dietary Supplement Label Like a Toxicologist

The anatomy of the panel

Every dietary supplement sold in the United States must carry a Supplement Facts panel, laid out according to federal rules ^[1]. From top to bottom it shows the serving size, the servings per container, a list of ingredients with the amount per serving, the percent Daily Value where one exists, and footnotes. Below or beside the panel come the other ingredients, the directions, cautions and the name and address of the company responsible.

Learning to read the panel takes five minutes and saves money for years. It also lets you check a sales page against the product it is selling, which is often the most useful thing a buyer can do.

Serving size and servings per container

The serving size tells you what all the amounts refer to: one capsule, two tablets, a scoop, or, for Honey Harmony, 1 mL, one dropperful. If the directions tell you to take more than one serving a day, multiply every amount accordingly. If the sales page describes a different dose from the label, the label wins.

Servings per container tells you how long a bottle lasts and lets you calculate cost per day. Honey Harmony has 30 servings in a 30 mL bottle: one month at one dropperful a day. A product with a low price and few servings can cost more per day than one with a high price and many.

Units: mg, mcg, IU and mL

Amounts appear in milligrams (mg), micrograms (mcg, a thousandth of a milligram), occasionally international units for some vitamins, and grams for larger ingredients. The difference between mg and mcg is a factor of 1,000, and it is easy to misread. Honey Harmony's chromium is 7 mcg, which is 0.007 mg; its blend is 15.47 mg.

For liquids, the serving may be given in mL, but the ingredient amounts are still given by weight. Do not confuse the volume of the liquid with the amount of active ingredient it carries.

Percent Daily Value and the dagger

The % Daily Value column compares the amount with a reference intake for nutrients that have one, such as vitamins and minerals. Honey Harmony's 7 mcg of chromium is 20% of the 35 mcg Daily Value. A dagger (†) means no Daily Value has been established, which is the case for nearly all herbs and many amino acids.

The dagger is often misread. It does not mean the amount is safe, unsafe, high or low; it means there is no official reference point. To judge a botanical dose, you need the doses used in research, which you will not find on the label.

Proprietary blends

A proprietary blend lists one total weight for a group of ingredients, with the ingredients named in descending order by weight but without individual amounts ^[1]. Honey Harmony's blend is 15.47 mg for 21 ingredients.

When you see a blend, do two quick calculations. Divide the total by the number of ingredients to get the average share, about 0.74 mg each here. Then remember that no single ingredient can be more than the total. If the total is smaller than one research dose of the headline ingredient, the blend cannot contain an effective amount of it. Our guide to proprietary blends goes deeper.

Botanical names, plant parts and extracts

For herbs, a good label gives the common name, the Latin name, the part of the plant used and the form: powder, extract, tincture. The part matters because roots, leaves and seeds contain different compounds. Honey Harmony's sales page calls its ginseng an aerial extract, while the label says root extract; the label is the one that describes the bottle.

Extract ratios, such as 20:1, say how much starting plant went into each part of extract. They are useful but incomplete. A standardization figure, such as 25% gymnemic acids or 50% EGCG, tells you how much of the active compound is present, and that is the number research doses are usually based on. Honey Harmony gives ratios but no standardization.

Other ingredients

The other ingredients list everything that is not an active: capsule shells, fillers, sweeteners, flavors, preservatives and colors. For Honey Harmony: water, natural flavors, potassium sorbate, stevia, xylitol, citrus extract. Read this list for allergens and for anything you avoid. Two items here are worth knowing: xylitol, a sugar alcohol that is dangerous to dogs even in small amounts ^[2], and natural flavors, a broad term whose sources the label does not specify.

Directions and cautions

The directions are the dose the company stands behind. Exceeding them is not a fix for a weak product and may add risks. The cautions tell you who should not use the product; Honey Harmony's label excludes people under 18, pregnant or nursing women, and asks anyone with a medical condition to consult a physician. Read these before the marketing. If the sales page contradicts them, as Honey Harmony's capsule directions do, trust the label.

Who made it

The label must name the manufacturer, packer or distributor, with an address ^[1]. Often it names a distributor rather than the company that made the product, with wording such as distributed by. Honey Harmony's label names a distributor, Gex Corporation LLP, with a post office box in Ogden, Utah.

The phrase made in an FDA-registered facility appears on many labels. Food facilities must register with the FDA, and supplement makers must follow current good manufacturing practice ^[3], but registration is not approval and is not a test of the product.

Claims and the disclaimer

Supplements may make structure-and-function claims, such as supports healthy blood sugar levels, provided the label also carries the standard statement that the FDA has not evaluated the claim and that the product is not intended to diagnose, treat, cure or prevent any disease ^[4]. Claims to treat a disease, including diabetes, are not allowed for supplements. When a label or sales page claims to manage a disease, it has stepped outside the rules.

Seals and testing

Some products carry seals from independent programs that test whether a supplement contains what its label says and is free of certain contaminants. A seal is a useful sign of quality control, though it says nothing about whether the product works. Absent a seal, some companies publish certificates of analysis for each production lot. Honey Harmony shows neither; its quality claims are the FDA-registered facility line and made in the USA.

A five-minute routine

1. Find the serving size and multiply by the daily directions.
2. Note every printed amount, and the blend totals.
3. Divide each blend total by its number of ingredients.
4. Look up the research dose of the headline ingredient and compare.
5. Read other ingredients for allergens and pet hazards.
6. Read the cautions and the company name.
7. Compare the sales page with the label. Where they differ, the label describes the bottle.

Applied to Honey Harmony, the routine takes about five minutes and shows exactly what our ingredient ledger shows: one printed dose, one small blend, and a sales page that describes a different product.