Choosing a probiotic supplement can be daunting. “The FDA doesn't regulate supplements, and many times the client does not know what they are or are not getting,” notes Morra. Still, better probiotics share some common traits:
- They contain genetically identified, well-researched strains like those listed earlier. (An online search can reveal the level of research on any strain.)
- They’re free from all major allergens in addition to artificial colors, flavors, and preservatives.
- They have a guaranteed number of living units with the expiration date.
- They’re created using good manufacturing practices (GMP). Look for GMP certification or USP (U.S. Pharmacopeial Convention) verification around the label.
- They’re tested by a completely independent laboratory to verify label claims.
Some, but not all, quality probiotics need to be refrigerated. Freeze-dried capsules and soil-based probiotics generally don’t want it. If the label recommends refrigeration, be sure the seller has followed that instruction.
The number of colony-forming units (or CFUs) does not seem to be important, and more is not necessarily better. “When the probiotic is potent enough, you don’t need countless billions of units,” notes Rountree, adding that beneficial ranges will be different among probiotic categories.
With soil-based probiotics, for instance, 2 billion units are most likely enough to make a difference, while many Lacto-Bifido blends feature CFUs which range from 25 billion to 50 billion, plus some contain even more.
Opt for a probiotic that meets the criteria for a quality supplement over one that promises the highest quantity of CFUs.