How to read a supplement label in 60 seconds

You can learn most of what matters about a supplement in about a minute, standing in the aisle, before you've read a single marketing claim on the front. The front of the bottle is advertising. The back is where the truth is, and it's only four checks.

Check one: serving size

Flip to the Supplement Facts panel and find "serving size" first, because every number below it is per serving, not per capsule. "1,000 mg of magnesium" sounds great until the serving size is four capsules, which means each capsule has 250 mg and the bottle empties in a quarter of the time you assumed. Multiply the daily servings out. This single check reframes half the value comparisons you'll ever make.

Check two: the form of the nutrient

This is the fastest read on whether a company is serious. The good forms cost more and absorb better, and companies that care use them. Quick tells:

• Magnesium: glycinate or citrate (good) vs oxide (cheap filler) - Folate: methylfolate or 5-MTHF (good) vs folic acid (adequate, but a red flag in a premium product) - B12: methylcobalamin (good) vs cyanocobalamin (cheap)

The form is a company telling you, in small print, whether it spent money on you or on the label.

Check three: the third-party seal

Supplements aren't verified before sale the way drugs are, so independent testing is how you know what's in the bottle matches the label, and that it isn't contaminated. Look for USP, NSF, or Informed Sport (the last one matters if you're drug-tested for sport). These programs test identity, potency, and contaminants. They don't judge whether the supplement works (that's your job and ours), but they confirm you're getting what it says. No seal isn't automatically disqualifying, but on anything you'll take daily, it's worth wanting.

Check four: the proprietary-blend trap

If the panel lists a "proprietary blend, 750 mg" followed by a list of ingredients with no individual amounts, treat it as a company hiding the doses. The reason to hide doses is almost always that the exciting-sounding ingredients are present in trace, useless amounts (this is called "fairy dusting") while the cheap filler makes up the 750 mg. A company confident in its formula prints the numbers. A blend is a curtain.

Run those four (serving size, form, seal, blend) and you've filtered out most of the supplement aisle without engaging a single health claim. What's left is a much shorter list of bottles worth reading closely.

The meta-point, and it's the whole Pragma thesis in miniature: the label is a document written by people who mostly assume you won't read it. Reading it, even for sixty seconds, changes what they can get away with.