What is CFU: Decoding Probiotic Labels

Have you ever taken a close look at the label on your probiotic? Give it a look to ensure you know all the relevant information before adding it to your supplement routine. But when you do, you may notice "CFU." What is CFU? Is it a word? Is it an acronym? Is it a series of arbitrary letters selected to sound cool? What does "CFU" mean? All good questions.

The simplest answer to “what is CFU in probiotics” is this: CFU means "Colony Forming Units." Does that clear things up? I didn't think so! Like many things worth knowing, we will need to get into the nitty gritty a bit more to demystify the meaning of CFU and help you make informed choices when selecting probiotics. Nature Made^® is committed to providing a range of quality probiotic options and information so you can find our best probiotic for you.

How to Interpret CFU on Probiotic Labels

So, "CFU" means "Colony Forming Units," but that doesn't help too much, does it? What does "Colony Forming Units" mean? In order to understand that, first let’s talk about what probiotics are. Probiotic supplements provide beneficial live bacteria that help balance the gut microbiome.

These probiotic bacteria work by multiplying within the gut microbiome, forming bacterial colonies. Are you starting to see how it connects? "Colony Forming Units," or CFUs, are the number of live, viable bacterial cells in the probiotic supplement dose.[1] It is the number of "Units" that can "Form" these probiotic "Colonies."^†

As you might imagine with all things bacteria, the numbers we're dealing with are humongous. Because bacteria are tiny, we aren't just dealing with dozens, hundreds, or even thousands. Most dietary probiotic supplements have CFU levels in the billions. This can be written in words as “15 billion” or in numbers as “1 x 15¹⁰” rather than listing all the zeroes![1]

For example, Nature Made^® Extra Strength Probiotics provide 15 billion CFU from live cultures in one capsule. Next time you take a probiotic, consider the size of the capsule, tablet, or gummy, and try to think of how you would fit billions of anything in there. I couldn't do it! That’s why we have trusted scientists to do the formulating for us.

While we're generally dealing with large numbers, when it comes to probiotics, more isn't always better. Most probiotic supplements contain 1 to 15 billion CFU per dose, but higher CFU counts don’t always mean a better product.

According to the International Scientific Association for Probiotics and Prebiotics effective doses can range from 100 million to 50 billion CFU per dose.[2] Always take the suggested dose on the label, as the dose is determined by the amount that is needed to be consumed to obtain the desired benefit.[2] When testing for clinical efficacy, the strain and dosage of probiotic bacteria matter more than the CFU.

There are many different strains, genera, and species of probiotic bacteria. Each of these strains has a unique role in the gut microbiome, so it's essential to find out which strains are present in a probiotic. To do this, ensure the probiotic you choose clearly labels the strain included by checking the supplement facts label. For example, our Digestive Probiotics Extra Strength 8 Billion CFU per 2 Gummies include the strain Bacillus Coagulans IL-2 to help support digestive health.^†

Some probiotic products offer more than one strain in a single dose. These products can support gut health in multiple ways, but it's still important to make sure that every strain is backed by research showing its efficacy. Nature Made^® Probiotics 1 Billion CFU from Live Cultures Capsules provide probiotics that support both regularity and a healthy immune system.^†

One thing to remember when evaluating CFUs on probiotic products is that the CFU count reflects the surviving viable units at the end of the product's shelf life, not just at the beginning. This means that, if stored correctly according to the conditions on the label, you should get the listed CFU in each dose until the product reaches its expiration date.

Choosing the Right Probiotic for You

Now that we're all a bit more knowledgeable about "CFU", let's "see if you" can find the right probiotic for your unique needs. When browsing probiotic supplements, here are the key factors to consider:

1. CFU Count. This gives you information on the number of viable probiotic units provided in a dosage of the given supplement.
2. Probiotic Strain. This tells you what bacterial strain is provided, so you can determine the benefit. If the product includes more than one strain, it may offer more than one benefit.
3. Potency Guarantee. Nature Made^® Probiotics are made to our guaranteed purity and potency standards.
4. Brand Reputation. It's best to go with a trusted brand when choosing any supplement. Did you know that Nature Made^® is the #1 Pharmacist Recommended Vitamin & Supplement Brand?* Now you do!

Nature Made^®'s Probiotic Collection provides several ways to support your gut's natural balance with sources of probiotic bacteria. With clear labeling of CFU count, strain, and benefits, we hope to help you make an informed decision when choosing a probiotic.^†

CFU FAQs

Here are some frequently asked questions about CFUs and some quick answers. For more in-depth answers to some of your questions, check out “How Do You Know if Probiotics are Working?” and “When is the Best Time to Take Probiotics?”

Are Higher CFU Probiotics Better?

Probiotics with a higher CFU are not necessarily better than those with a lower CFU. Nature Made^®'s probiotic benefits are based on the dose used in clinical trials.^†

How Many CFU in a Probiotic Do I Need?

That depends on the probiotic! To get the intended level of CFU in your probiotic supplement, Nature Made^® recommends following the suggested use and dosage instructions on the label.

Can CFU Decrease Over Time?

The amount listed on the label is determined by the CFUs remaining at the end of the product's shelf life. As probiotics are living things, they can decrease over time. Storing your probiotic supplement in a cool, dry place at or below 75°F (23°C) and consuming them before the expiration date can help ensure you get the dosage listed on the label of your daily supplement.

How to get the most of taking probiotics? It's recommended to take your probiotics with a meal and a cool or room-temperature beverage. Hot beverages and stomach acid can damage the bacteria in the probiotic, affecting how many viable CFUs you get from each dose.[3]

Take the Guesswork Out of Choosing Probiotics

Now you know what a "CFU" stands for, what exactly "Colony Forming Units" are, and the key criteria for selecting a quality probiotic. If you're looking for high-quality, clearly labeled probiotic supplements to help support your gut’s natural balance, check out Nature Made^®'s Probiotic Collection.^†

† These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.

References

1. National Institutes of Health. Probiotics. Nih.gov. Published November 3, 2023. https://ods.od.nih.gov/factsheets/Probiotics-HealthProfessional/
2. Probiotics - International Scientific Association for Probiotics and Prebiotics (ISAPP). International Scientific Association for Probiotics and Prebiotics (ISAPP). Published 2019. https://isappscience.org/for-consumers/learn/probiotics/
3. Tompkins TA, Mainville I, Arcand Y. The impact of meals on a probiotic during transit through a model of the human upper gastrointestinal tract. Benef Microbes. 2011;2(4):295-303. doi:10.3920/BM2011.0022 https://pubmed.ncbi.nlm.nih.gov/22146689/