Four numbers a supplement label hides in plain sight

1. The serving size, not the capsule size

The most common gap between what a label says and what a buyer understands is the serving. A front label states the amount in one unit; the Supplement Facts panel states how many units make a serving. When those differ, every downstream calculation changes — the strength you are taking, how long the bottle lasts, and what it costs per day.

2. What a proprietary blend actually withholds

A proprietary blend lists several ingredients and gives one combined weight. Regulations require ingredients to appear in descending order by quantity, so you learn the ranking. You do not learn any single amount. If an ingredient has good evidence at 400 mg, and it sits third in a 500 mg blend, it is arithmetically impossible for it to be present at the studied dose — and the label will never say so.

This matters most precisely where dose is the whole question. For ingredients whose evidence is dose-dependent, a blend converts a checkable claim into an unfalsifiable one. That is why an undisclosed blend caps an assessment on this site regardless of how good the rest of the formula looks.

3. Caffeine arrives under several names

Guarana, yerba mate, green tea extract and plain caffeine anhydrous can all appear on one panel, each contributing to a total the label never adds up for you. Then there is the coffee you already drank. The number that affects your sleep and heart rate is the sum, not the largest single line.

• Add every stimulant-bearing ingredient on the panel, not just the line marked caffeine.
• Check whether an extract is decaffeinated — some are, and the label will say so if it is.
• Count your own intake from coffee and tea in the same total.

4. Units that switch mid-label

Vitamin D is measured in both micrograms and International Units, and they differ by a factor of forty: 25 mcg is 1,000 IU. A product page can lead with one figure in the title and the other in the description, and we have found manufacturer pages that contradict themselves between the two. A reader comparing a mcg number against an IU number can be forty times wrong about relative strength.

The same trap appears with minerals, where compound weight and elemental weight are different numbers for the same capsule. A magnesium product quoting the weight of magnesium bisglycinate is not quoting the amount of magnesium.

The thirty-second habit

Turn the bottle over before you look at the front. Find the serving size and the servings per container, then divide the price by the servings. Check whether every active has its own number. Add the stimulants. If those four checks pass, the product is at least honestly presented, which is a lower bar than being effective but a necessary one.