Probiotic supplements continue to gain traction worldwide. The global probiotics market was valued at $87.70 billion in 2023 and is projected to reach $220.14 billion by 2030, with a compounded annual growth rate (CAGR) of 14.1%.1Probiotics Market Size, Share & Trends Analysis Report By Product, By Ingredient (Bacteria, Yeast), By Distribution Channel, By End Use (Human Probiotics, Animal Probiotics), By Region, And Segment Forecasts, 2024 – 2030. Grand View Research. Retrieved September 4, 2025 from https://www.grandviewresearch.com/industry-analysis/probiotics-market. Amid this rapid growth, one question we receive quite frequently, especially from new or aspiring dietary supplement brand owners, is: “What are CFUs in probiotics?”
CFU stands for colony-forming units, the measurement used to indicate the number of viable microorganisms in a probiotic product. Unlike other nutraceutical ingredients that are measured in grams, milligrams, or micrograms, probiotics are quantified in CFUs to reflect their unique nature.
In this article, we’ll cover how CFUs are measured, the factors that influence CFU counts, and how brand owners and formulators can determine the right levels for their products in development.
What Are Colony Forming Units (CFUs) in Probiotics?
Now that we know CFU stands for colony-forming units, what exactly does the CFU mean in probiotics?
CFU is a microbiological term that refers to the number of viable (living) microorganisms, such as probiotic bacteria, in a sample that can grow and form colonies on a nutrient medium under specific conditions. In the human body, these probiotic bacteria may establish colonies in the gut and remain for some time, or they may simply pass through as transients while still interacting with the gastrointestinal environment.
For supplement brand owners, CFUs are a critical unit of measurement because they provide a standardized way to describe the quantity of probiotic organisms in a formula. This helps ensure consistency, quality, and transparency in product labeling and development.
Why Are CFUs Important?
CFUs are important because they provide a measure of a probiotic’s potency and viability. Unlike standard nutraceutical ingredients, such as vitamin C, where potency is expressed by weight in milligrams, probiotics require a different approach. Because probiotics are living organisms, their effectiveness cannot be measured by weight alone.
How Many CFUs Should a Probiotic Have?
So, how many CFU should a probiotic have? There is no single answer, as it depends on factors such as the probiotic strain, the intended application, and the available scientific research. Different strains have been studied at different CFU levels, which makes it clear that the “right amount” can vary widely.
Examples from published research include:
- Lactobacillus rhamnosus NH001 – 6 billion CFU during pregnancy is shown to help postpartum mood.2Slykerman RF, Hood F, Wickens K, Thompson JMD, Barthow C, Murphy R, Kang J, Rowden J, Stone P, Crane J, Stanley T, Abels P, Purdie G, Maude R, Mitchell EA; Probiotic in Pregnancy Study Group. Effect of Lactobacillus rhamnosus HN001 in Pregnancy on Postpartum Symptoms of Depression and Anxiety: A Randomised Double-blind Placebo-controlled Trial. EBioMedicine. 2017 Oct;24:159-165. doi: 10.1016/j.ebiom.2017.09.013. Epub 2017 Sep 14. PMID: 28943228; PMCID: PMC5652021.
- Bacillus subtilis DE111 – 1 billion CFU in adults was shown to promote healthy bowel movements.3Cuentas AM, Deaton J, Davidson J, Ardita C. The Effect of Bacillus subtilis DE111 on the Daily Bowel Movement Profile for People with Occasional Gastrointestinal Irregularity. J Prob Health. 2017; 5: 189
- Streptococcus salivarius K12 – 5 billion CFU in adults was shown to promote healthy mucous membranes in the throat.4Di Pierro F, Adami T, Rapacioli G, Giardini N, Streitberger C. Clinical evaluation of the oral probiotic Streptococcus salivarius K12 in the prevention of recurrent pharyngitis and/or tonsillitis caused by Streptococcus pyogenes in adults. Expert Opin Biol Ther. 2013 Mar;13(3):339-43.
- Akkermansia muciniphila – 10 billion CFU in overweight adults was shown to promote weight loss and healthy cardiometabolic parameters.5Depommier C, Everard A, Druart C, Plovier H, Van Hul M, Vieira-Silva S et al (2019) Supplementation with Akkermansia muciniphila in overweight and obese human volunteers: a proof-of-concept exploratory study. Nat Med 25(7):1096–1103.
Of course, these examples are only a drop in the bucket since there are hundreds of studies on the use of probiotics in human health and wellness. Nevertheless, they serve to demonstrate that the answer to “what is the best amount of CFU count for probiotics?” differs significantly from one strain to another based on the focus of the research and the population being studied.
For supplement brand owners and key decision makers, the key takeaway is that CFU counts should be based on credible research and the intended positioning of the product. Partnering with an experienced probiotic supplement manufacturer can provide valuable guidance in determining the most appropriate CFU levels for your formulations.
Factors That Influence the CFU Count in Probiotics
Are high CFU probiotics always better? In some cases, yes; in others, no. Beyond the research conducted on specific probiotic strains, several additional factors influence the CFU count in a finished product.
Specific Probiotic Strain
Each probiotic strain has its own unique structure and sensitivities. Remember, these are live organisms and, just like other life forms, there will be differences within a given family. Some of these differences affect how a strain responds to manufacturing, storage, and stress conditions, as outlined below.
Manufacturing Processes
During manufacturing, moisture can negatively impact the stability of probiotics in supplemental form. As a result, some probiotic strains do not play well with other nutraceuticals that have a bit more moisture than others. Consequently, it isn’t always a good thing to include probiotics in multi-ingredient formulas since some of those ingredients may contain more moisture than the probiotic can handle. In other cases, the probiotic strain will do just fine when included with other nutraceuticals.
This is why working with an experienced probiotic contract manufacturing partner is critical. They can guide you in selecting strains that are compatible with your formula.
Storage Conditions
In addition to moisture, heat can negatively affect probiotic stability. For example, research6Gardiner GE, O’Sullivan E, Kelly J, Auty MA, Fitzgerald GF, Collins JK, Ross RP, Stanton C. Comparative survival rates of human-derived probiotic Lactobacillus paracasei and L. salivarius strains during heat treatment and spray drying. Appl Environ Microbiol. 2000 Jun;66(6):2605-12. doi: 10.1128/AEM.66.6.2605-2612.2000. PMID: 10831444; PMCID: PMC110587. has shown that most Lactobacilli strains tested lost viability with increased temperatures. Consequently, some probiotics need a temperature-controlled and humidity-controlled environment to maintain their CFU count.
Working with a reputable contract development and manufacturing organization (CDMO) that has experience with probiotics and offers temperature- and humidity-controlled storage facilities to maintain CFUs and ensure the viability of the finished supplement is of paramount importance.
Shelf Life
Because probiotics are alive, their shelf life is typically shorter than most nutraceuticals. While standard supplements often maintain potency for 24 months, many probiotics remain stable for only 6–12 months. At Vitaquest, when manufacturing probiotic supplements, we may use 400% overage or more, when necessary, to help maintain stability for as long as possible. Consequently, verifying the CFU count of the finished supplement is recommended.
Stress Tolerance
“Stress tolerance” refers to how well probiotics survive gastrointestinal conditions such as stomach acid, bile salts, and digestive enzymes. For this reason, many studies use higher CFU counts to increase the likelihood that enough survive and reach the intestines intact. In this case, the answer to the question, “Is more CFU in probiotics better?” is yes. However, probiotics in the Bacillus genus are spore-forming. The spore is a naturally occurring protective encasement that allows the probiotic within to survive transit through the stomach and small intestine intact, retaining its potency. So, probiotics in this genus don’t require a higher CFU.
Does a Higher CFU Count Always Lead to Better Results?
We live in a society where people often assume “more is better,” but that is not necessarily true when it comes to probiotics.
A higher CFU count may be appropriate if the strain in question is sensitive and likely to lose viability during transit through the gastrointestinal tract. Even then, CFU levels should be based on studies that establish an appropriate dosage. Exceeding the amounts supported by research is not recommended, as excessively high levels of a single strain may disrupt overall balance. The most prudent approach is to align CFU counts with levels shown in human research to be safe and effective.
Wrapping up the Discussion on CFUs in Probiotics
In this article, we addressed the question “What are CFUs in probiotics?” and why they are critical in product development. CFUs measure the potency and viability of probiotic strains, with counts influenced by factors such as strain type, manufacturing, storage, and shelf life. Higher CFU counts are not always better; the key is aligning dosage with credible research. By understanding CFUs, supplement brand owners can make informed decisions that ensure product quality and consumer confidence.
If your goal is to enter the probiotic market with your own supplement, you’ll want to continue learning about probiotics. Perusing the website for the International Scientific Association for Probiotics and Prebiotics is a good resource. Another good resource should be the CDMO you choose to manufacture your probiotic supplement.
Vitaquest is the largest custom, non-originator contract manufacturer of probiotic dietary supplements in the United States, proudly producing more than 50 million retail units of finished probiotic products annually. With over 45 years of dietary supplement contract manufacturing experience and more than 100 probiotic strains available, Vitaquest can help you create a superior probiotic supplement product for your business.
To learn how we can help you “Deliver What’s Next” in probiotic supplements, call 800-526-9095 to speak with one of our knowledgeable production specialists or request a nutraceutical manufacturing price quote if you’ve already finalized your project requirements!
Frequently Asked Questions About CFUs in Probiotics
Do CFUs in probiotics remain active in the digestive system?
It all depends on the probiotic strain being used. During their journey through the gastrointestinal tract, many probiotics can be destroyed and/or lose potency when they encounter stomach acid and bile. Others, such as those in the Bacillus genus, produce a natural spore encasement that protects them, allowing the probiotic to remain intact and retain its potency.
Should CFU counts be adjusted depending on the delivery format of the probiotic?
It is less about the delivery format and more about the overall stability of the probiotic strain. Some strains are highly sensitive and can be easily compromised. For example, at Vitaquest, when manufacturing probiotic supplements, we may use 400% overage or more. In other cases, the probiotic strain is very hardy and doesn’t require such a high overage.
How are Colony Forming Units Measured?
They are measured by culturing the probiotic microorganisms on a growth medium and counting the colonies that form. Typically, this consists of placing a sample of the probiotic on a sterile Petri dish plate with an agar-based growth medium derived from seaweed.
