Don’t Buy a Probiotic Until You Can Read These Three Lines
The useful information is usually smaller than the promise on the front.
Turn the package around. Ignore words such as “advanced,” “balance” and “maximum” for a moment. Your first job is to find out what organism is actually present, how much is promised, and whether that amount is expected to remain through the end of shelf life.

1. Find the full identity
A microorganism can be listed by genus, species and strain—for example, three increasingly specific parts of a name. Benefits observed with one strain should not automatically be assigned to another strain in the same species. If no strain is shown, connecting the label to a particular study becomes harder.
2. Check the amount—and when it applies
Live probiotics are often measured in colony-forming units (CFUs). Look for whether the stated count applies at manufacture or through expiration. A larger number is not automatically better; an appropriate dose depends on the organism and purpose studied. Heat-killed preparations are different and may use other measures.
3. Read storage and expiration instructions
Heat and moisture can affect some live organisms. Follow the product’s storage directions and check the expiration date. A shelf-stable claim should not override instructions printed on the label.
Then inspect the claims
Ask whether the promised outcome was studied using the same strain, dose, format and type of participant. Testimonials and an ingredient’s general reputation are not substitutes for product-specific evidence. In the United States, dietary supplements are not approved by the FDA for effectiveness before they reach the market.