Start with the serving size
Everything on a supplement label is expressed per serving — and a serving may be one capsule or six. Before comparing prices or doses across products, normalize to the same serving count. A bottle that looks cheaper often just contains fewer servings.
Read the Supplement Facts panel, not the front
The front of the box is marketing; the Supplement Facts panel is the regulated part. Look for each ingredient's form (magnesium oxide and magnesium glycinate are not interchangeable) and its exact amount per serving.
Treat proprietary blends as missing information
A 'proprietary blend' discloses a total weight but hides individual amounts. That means you cannot compare the dose to research. It is the single most common red flag we encounter in reviews — not proof of a bad product, but a transparency failure you should price in.
Understand %DV — and its absence
Percent Daily Value tells you how a nutrient amount compares to general daily reference intakes. Botanical extracts usually have no %DV because no reference exists; for those, the only useful comparison is against amounts used in published studies.
Scan the 'Other Ingredients' line
Capsule materials, fillers, sweeteners and allergens live here. If you avoid gelatin, soy, dairy or artificial colors, this line matters more than the front label.
Decode the claim language
US supplements may make 'structure/function' claims ('supports…', 'helps maintain…') but not disease claims ('treats…', 'cures…'). A label or sales page promising to reverse a disease is not just optimistic — it is a compliance red flag about the whole operation.
A 60-second pre-purchase checklist
Named ingredient forms with disclosed amounts; doses comparable to studies; no essential information buried in a blend; allergens acceptable to you; realistic claims; a published refund policy; and a price per day you would happily pay for a modest, non-guaranteed effect.
Where to go next
See these habits applied in any of our product reviews, or start from the ingredient research library to understand what the amounts on a label actually mean.