How to read a supplement label

The Supplement Facts panel holds almost everything you need to judge a product — if you know where to look. Here's a quick tour.

Serving size

Start here. The amounts listed are per serving, and a serving might be two or three capsules, not one. A bottle of 120 capsules at three per serving is only a 40-day supply. Comparing two products means comparing them per serving, not per capsule.

Amount per serving and % Daily Value

This shows how much of each nutrient you get and, for many vitamins and minerals, what percentage of the recommended daily intake that represents. A %DV over 100% isn't automatically better — for some nutrients, much higher amounts add no benefit and can carry risk.

The form of each ingredient

Look at the exact form in parentheses — magnesium (as magnesium glycinate), or vitamin B12 (as methylcobalamin). Forms differ in how well they're absorbed and tolerated, and this is often where a quality product sets itself apart.

The 'Other ingredients' line

Below the panel is a list of everything else: capsule material, fillers, flow agents, colors, and allergens. Shorter is usually better. This is also where you'll spot things you may want to avoid, like certain allergens or artificial colors.

Proprietary blends

If you see 'proprietary blend' followed by a single total weight and a list of ingredients with no individual amounts, be cautious. You can't tell how much of each ingredient you're getting, which makes it impossible to compare against the research.

Dates and seals

Check the expiration date, and look for a third-party testing seal (NSF, USP, Informed Choice). The front-of-bottle marketing is the least useful part of the package — the Supplement Facts panel is where the truth is.