CFU
Also: colony-forming units
Colony-forming units, the standard probiotic label estimate for how many viable microbes a serving contains.
Definition of “CFU”
CFU stands for colony-forming units. It is the standard way probiotic labels estimate the number of live organisms that are capable of reproducing under the testing conditions used. That is why the number appears so often in gut-support shopping.
The term is useful, but it is not the whole story. A higher CFU count does not automatically mean a better product. Strain selection, stability, storage, and whether the formula actually matches the intended use matter just as much.
“CFU” In Practice
A probiotic label might say 10 billion CFU, which tells you the estimated count of viable microbes in a serving, not whether every strain is equally relevant to your goal.
Worth Knowing About “CFU”
CFU is a count estimate, not a quality guarantee. It helps compare products, but it does not replace questions about strains, heat stability, or shelf handling.