How to read a supplement label in 2 minutes
The Supplement Facts panel tells you more than the front of the bottle. Here is a 2 minute check: serving size, amounts, upper limits, blends, claims and quality seals.
Quick answer
Skip the front of the bottle and go straight to the Supplement Facts panel. It lists the serving size, the amount of each ingredient per serving and the other ingredients, according to the NIH.
Then check 3 things: that no nutrient goes over its upper limit, that no proprietary blend hides the doses, and whether the product has a quality seal from USP, NSF or ConsumerLab.
Start with what the label can tell you
The FDA does not approve supplements before they are sold. Supplement companies are responsible for having evidence that their products are safe and that their label claims are truthful and not misleading, according to the NIH.
So the label is your best tool. Two minutes of reading tells you what you are really taking.
The 2 minute label check
Find the serving size
Every number on the panel is for one serving. If a serving is 2 capsules and you take 1, cut every number in half.
Read the amount per serving
Each ingredient shows an amount in mg or mcg. Vitamin D may also show IU. 1 mcg of vitamin D equals 40 IU, so 25 mcg is 1,000 IU (NIH). 1 mg equals 1,000 mcg.
Check the % Daily Value
The % DV is the share of the Daily Value that one serving gives you, as defined by the FDA. A number over 100% means one serving gives you more than the Daily Value. That is your cue to check the upper limit table below.
Look for a proprietary blend
A “proprietary blend” only has to list its total weight. The ingredients inside are listed from most to least by weight, but the amount of each one is not shown. Vitamins and minerals with a Daily Value must still be listed with their own amounts.
Scan the other ingredients
The label also lists the other ingredients. Check for anything you avoid, like gelatin, dyes or a sugar alcohol.
Read claims for what they are
A claim like “supports immune health” is a structure/function claim. The FDA does not approve these claims before they are used. On a supplement, the claim must come with this line: “This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.” (21 CFR 101.93)
Look for a quality seal
USP, NSF International and ConsumerLab.com test supplements. The NIH says their seals mean a product was properly made, contains the ingredients on the label and does not contain harmful levels of contaminants. The seals do not mean a product is safe or that it works.
Upper limits to know
More is not always better. These are the adult upper limits for nutrients you will often find in supplements. Most of these limits count food, drinks and supplements together. The magnesium limit counts supplements and medicines only.
| Nutrient | Adult upper limit | Too much can cause |
|---|---|---|
| Vitamin A (preformed) | 3,000 mcg | Headache, blurred vision and nausea. Birth defects if taken in pregnancy. |
| Vitamin D | 100 mcg (4,000 IU) | Nausea, vomiting, muscle weakness, confusion and kidney stones |
| Vitamin B6 | 100 mg | Severe nerve damage after a year or more of high doses |
| Iron | 45 mg | Accidental overdose is a leading cause of fatal poisoning in children under 6 |
| Zinc | 40 mg | Nausea, vomiting and headaches. Low copper over time. |
| Magnesium | 350 mg from supplements | Diarrhea, nausea and cramping |
Tell your doctor what you take
Supplements can interact with medicines. For example, vitamin K can make the blood thinner warfarin work less well, according to the NIH.
Tell your doctors, dentist and pharmacist about every supplement you take. Ask about your supplements before any surgery.
FAQ
What does % Daily Value mean?
It is the share of the Daily Value for a nutrient that one serving gives you, as defined by the FDA.
Is a proprietary blend bad?
Not always, but you can’t see the dose of each ingredient inside it. FDA rules require the blend’s total weight, not the amount of each ingredient.
Does a USP or NSF seal mean a supplement works?
No. The NIH says seals show a product was properly made and contains what the label lists. They do not guarantee it is safe or effective.
Does the FDA approve supplements?
No. Supplements do not need FDA approval before they are sold. The company is responsible for safety and for truthful labels, according to the NIH.
What is the difference between mg and mcg?
1 mg (milligram) equals 1,000 mcg (micrograms). Vitamin D, for example, is shown in mcg.
Sources
- NIH Office of Dietary Supplements: Dietary Supplements: What You Need To Know
- FDA: Dietary Supplement Labeling Guide, Chapter IV
- FDA: Structure/Function Claims
- 21 CFR 101.93: Certain types of statements for dietary supplements
- NIH Office of Dietary Supplements: Vitamin D fact sheet for consumers
- NIH Office of Dietary Supplements: Vitamin D fact sheet for health professionals
- NIH Office of Dietary Supplements: Vitamin A fact sheet for consumers
- NIH Office of Dietary Supplements: Vitamin B6 fact sheet for consumers
- NIH Office of Dietary Supplements: Iron fact sheet for consumers
- NIH Office of Dietary Supplements: Zinc fact sheet for consumers
- NIH Office of Dietary Supplements: Magnesium fact sheet for consumers
This page is general information, not medical advice. Check with a doctor before you start a new supplement. Medical disclaimer