Ingredient guide
Probiotics: species, strains, and CFUs
Decode the naming and quantity information commonly shown on probiotic labels.
Whole for Good editorial guide · Content version July 18, 2026
Names can be specific
A probiotic label may identify genus, species, and strain. Products containing the same species are not necessarily identical when their strains or combinations differ.
CFUs describe quantity
Colony-forming units estimate the number of viable microorganisms. Review whether the stated quantity applies at manufacture or through the end of shelf life.
Storage and context matter
Follow the label’s storage directions. People with serious underlying illness or weakened immune systems should seek clinical guidance before use.