How to read a Supplement Facts label

At a glance: check these 6 things

Read the Supplement Facts panel on the back of the bottle from top to bottom. Check these 6 things and you will know how much is inside, how many capsules a day it takes, and what the label is not telling you.

Then look at any certification seals (USP, NSF and others) and the FDA statement on the bottle, and you are done. Here is what a panel looks like:

① Serving Size: how many capsules is one serving?

This is the first line to read. Every number below it is based on one serving.

Under FDA rules, a serving is the amount the label tells you to take at one time. If there is no recommendation, it is 1 unit. So products with a low amount per capsule often have a serving size of 2–4 capsules.

② Amount Per Serving: the numbers are per serving, not per capsule

The numbers under "Amount Per Serving" are the amount in the whole serving. To find the amount in one capsule, divide by the number of capsules in the serving size.

The two magnesium products above show amounts that differ by 2x per serving, but each capsule holds the same amount. When you compare products, line them up by "how much per capsule."

If the label says "Each Tablet Contains," the numbers are per tablet. If there are several columns, like "Amount per 2 Tablets," each column is for a different number of tablets.

③ % Daily Value and the * and † symbols

% Daily Value (%DV) tells you what percent of the daily target you get. It is the amount divided by the adult Daily Value set by the FDA.

• Over 100% is not automatically dangerous. The Daily Value is a target, not an upper limit you must stay under. But for fat-soluble vitamins like A and D, and for minerals like iron and zinc, add up the amounts if you take more than one product.
• If you see a symbol like * or † in the %DV column, look at the footnote below the panel. It usually says "Daily Value not established." This shows up for things like EPA, DHA, probiotics, herbs and collagen, which have no daily target.
• The symbol varies by brand. Some use *, some use †. "* Percent Daily Values are based on a 2,000 calorie diet" is a different footnote that goes with lines like calories and carbohydrates.

④ The number in the name vs. the amount you actually get

This is the most confusing part of any label. Minerals come bound to other molecules as a "compound." The big number on the front of the bottle is often the weight of the whole compound. The pure (elemental) amount your body gets is lower.

Under FDA rules, the numbers in the Supplement Facts panel are for the elemental amount. So "Magnesium (as magnesium glycinate) 100 mg" means 100 mg of elemental magnesium. The part in parentheses tells you which form was used.

Fish oil has the same trap. "Fish Oil 1,000 mg" is the weight of all the oil in the capsule. The actual omega-3 is the lines below it: EPA plus DHA.

Both say 1,000 mg, but one has more than twice the omega-3. See the numbers for each product in our omega-3 EPA + DHA comparison. Dose guidelines are on the magnesium and omega-3 pages.

⑤ Units: mg, mcg, IU, DFE, RAE, CFU

Different units can make the same product look very different. Match the units before you compare.

• Newer labels use mcg and mg instead of IU. Vitamin D is often shown as "50 mcg (2,000 IU)" with IU in parentheses. Vitamin A is now in mcg RAE, and vitamin E is in mg. Convert when you compare with an older label.
• Folate shows two numbers. For example: "Folate 680 mcg DFE (400 mcg folic acid)." The first is the adjusted amount, and the number in parentheses is the folic acid actually added. There is no official conversion for active folate (methylfolate) yet, so labels may differ. See folate for more.
• Dose guidelines are on the vitamin A and vitamin D pages.

For probiotic CFU, what matters is "as of when."

⑥ Proprietary Blend and Other Ingredients

A "Proprietary Blend" hides the amount of each ingredient. The law lets companies keep their recipe ratios private.

• By rule, ingredients in a blend are listed from most to least by weight. So the first one is the largest.
• But the ones at the end may be present in very small amounts. There is no way to check whether you are getting the amount used in studies.
• Ingredients with a Daily Value, like vitamins and minerals, must still be listed with their own amounts, even inside a blend.

"Other Ingredients" are listed below the panel. They are not the active ingredients. They are what the capsule or tablet is made of.

If you have allergies, also check the allergen line below, such as "Contains: Fish (anchovy), Soy," and any "Made in a facility that also processes…" statement.

Certification seals: what they do and don't mean

In the US, the FDA does not approve supplements before they are sold. So many people look for seals from third-party testers as a sign of quality. But each seal checks different things.

• No seal does not mean a bad product. Certification is optional and the company pays to apply, so many good products have no seal.
• "GMP" or "Made in a cGMP facility" is not a certification seal. All US supplement makers are already required to follow FDA manufacturing rules (cGMP).
• To check if a seal is real, search the product name in the certified product lists on the USP or NSF websites.

What "These statements have not been evaluated by the FDA" means

Almost every bottle has this on the side:

In plain words: "The FDA has not reviewed these benefit claims, and this product is not meant to diagnose, treat or prevent disease."

Summary + check it with a photo

1. Serving Size: how many capsules make one serving
2. Amount Per Serving: amount per serving ÷ number of capsules = amount per capsule
3. %DV: over 100% is not automatically dangerous, but add up fat-soluble vitamins, iron and zinc. * or † means no Daily Value
4. Actual amount: for minerals, the number on the "Magnesium (as …)" line; for fish oil, EPA + DHA
5. Units: compare in the same unit (mcg, IU, DFE, RAE); for probiotics, look for CFU "through expiration"
6. Hidden info: a Proprietary Blend hides each amount; check Other Ingredients for capsule material and allergens

If the label is hard to read, upload a photo of the Supplement Facts panel to our supplement check. The text in your photo is read on your device and is not sent to our server. You can also look up product labels in the NIH Dietary Supplement Label Database (DSLD), run by the US government.

If you take any medication, talk to your doctor or pharmacist before starting a new supplement. To see whether you can pay with HSA or FSA, read our HSA and FSA guide.

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