How Much Probiotic Bacteria is Good?

How Much Probiotic Bacteria is Good?


What is CFU?

cfu, colony forming unit
The Potency of probiotics is related to the amount of bacteria. Generally, a higher amount of probiotic bacteria is better for you. When you see the supplement facts of probiotics, you will notice an unusual word after the number of bacteria, CFU. CFU stands for “colony forming unit.” It is used to quantify the number of bacteria in probiotics that are capable of dividing and forming colonies. In other words, CFU means the number of living bacteria (1). To find the CFU, microbes are cultured in petri dishes and the number of growing dots (colonies) are counted by observations with the naked eyes or counting machines. 

How Much Bacteria Do We Need?

How much probiotic bacteria is good enough for your body? 10 to 20 billion CFU per day for adults
How much probiotic bacteria is good enough for your body? Some probiotic products don’t even list the amount of bacteria their product contains. Common dosages in products range from 10 to 20 billion CFU per day for adults (2). This amount is 0.1% to 0.2% of the total number of bacteria (100 trillion) in our body.  Because it is known that fairly high dosages of probiotics are safe, it is okay to get higher doses. However, dosages higher than 20 billion CFU are generally more expensive and unnecessary.


  1. Colony-forming unit. (2016, April 20). In Wikipedia, The Free Encyclopedia. Retrieved 17:21, May 26, 2016, from
  2. Kligler B, Cohrssen A. Probiotics. Am Fam Physician. 2008 Nov 1 ;78(9):1073-8.