Probiotic potency

Why are CFU important?

CFU stands for colony forming units, which is the way to quantify the number of live bacteria in a probiotic product. It is one of the most important topics we discuss with our customers, who are developing new probiotic products. Listen to Caroline Montelius, PhD, Science Manager at Probi when she is explaining how this matters for your product. Is a higher CFU value more effective? And why is the dose not given in milligram (mg)? These are some of the questions that will be answers in the video below.

What you need to know about CFU.

Video transcription:

The definition of probiotics, stated by the World health organization in 2001, is “live microorganisms which when administered in adequate amounts confer a health benefit on the host”. Therefore, if you are going to use the word “probiotics”, then the product should by definition have the number of bacteria, the CFU, which has been found to be effective in the host. In addition, at least one study should have been conducted, with the demographic population for whom the product is intended.

Is a higher CFU better compared to a lower value of CFU?

There is no evidence that a higher dose than what has been clinically shown to be effective is more efficacious. There are several products on the market today with high CFU counts, which often contain multiple strains. These products may be effective; however, the strains in the formulation or the product itself have not always been tested in clinical studies. To ensure the effectiveness of your product, it is preferable to choose a single strain or a combination of strains, which have been clinically tested to be compatible or even to enhance each other’s effect, at a clinically tested CFU dosage.

A product with a very high CFU count may logically seem to be better or improved but this may not be an accurate evaluation. Before developing a new probiotic product and deciding which strains and CFU potency, you should first ask yourself if you want the product to come with clinical efficacy. If your goal is to have a clinically effective probiotic product, then you must carefully select strains best suited for the health condition and demographic population you are targeting.

Repetitive clinical studies utilizing the same strain, same CFU dosage and same indication are usually the preferred option to ensure the consumer can trust the product. The lesson to be learned here is when it comes to probiotic supplements “the more the merrier” is not an accurate description.

Why is the dose not given in milligram (mg) or gram (g)?

Probiotic strains are usually sold from the manufacturer or supplier either as finished products or as a bulk powder. The bulk powder can have different concentrations of bacteria, meaning that 200mg of one strain is not equal to 200mg of another strain. Probiotics should always be measured by CFU potency, which accurately provides the number of live bacteria. In 200mg of powder, you could have 100 Billion CFU, 10 Billion CFU, 1 Billion CFU, or potentially no CFU at all if the probiotics have not been manufactured or stored properly.

If you are interested in learning more about probiotics, CFU counts, or anything else concerning the microbiome – please reach out at


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