Probiotic Labels: CFU Count, Expiration vs Manufacture, Strain Names and Storage

Probiotic labels carry numbers you will not see on most other supplements: a weight in milligrams, a count in the billions of “CFUs”, a three-part name such as Lactobacillus rhamnosus GG, and sometimes a promise about when that count still holds. This explainer covers only what is special about probiotic labels. For the Supplement Facts panel as a whole, start with our guide to reading a supplement label. Our worked examples are the two products we carry that list live cultures: Culturelle Digestive Daily Probiotic (30 capsules), a probiotic on its own, and Amazing Grass Super Greens, Original, a greens powder with one probiotic line.

How we wrote this: the Culturelle details come from the Culturelle product page and its Supplement Facts image, plus the NIH Dietary Supplement Label Database record for Digestive Daily Probiotic. The Amazing Grass details come from the Supplement Facts image on the Amazing Grass product page. All were viewed in October 2026. The labeling policy is FDA’s draft guidance on quantitative labeling of dietary supplements containing live microbials (September 2018). We describe what the labels and the guidance say. We have not tested these products, the package in your hand may be a different version, and this is not medical advice. Whether a probiotic makes sense for you is a question for your doctor.

Step 1: Check the serving size

Every number on the panel is per serving, so read the serving line first.

• Culturelle Digestive Daily: One (1) Capsule per serving.
• Amazing Grass Super Greens, Original: 8 g (about 1 scoop) per serving, 30 servings per container. The probiotic is one ingredient among many in that scoop.

Some probiotic products use two capsules, a packet or several gummies per serving. If the serving is more than one piece, divide before you compare.

Step 2: Weight comes first, CFUs come second

Under FDA’s Supplement Facts rules, a live microbial ingredient has to be declared by weight, usually in milligrams. The 2018 draft guidance says FDA does not intend to object if a brand also gives the count in colony forming units (CFUs), as long as a few conditions are met. The main ones:

• The weight is listed first.
• The CFU count is clearly separate from the weight, for example in parentheses or on its own sub-line.
• The count is written in plain terms, such as “10 billion”.
• The count includes only live microbes, not dead or nonviable ones.
• Live microbes in a proprietary blend are listed in descending order by weight.

Here is how our two examples show it:

• Culturelle: Lactobacillus rhamnosus GG, 40 mg (10 billion CFUs).
• Amazing Grass: Bacillus subtilis DE111 (1 Billion CFU), with 10 mg in the amount column. Here the count sits beside the strain name rather than under the weight.

A CFU is a measure of microbial cells that can still grow and form a colony in a lab count. FDA’s guidance explains why the weight alone falls short: it does not show how many of the cells are alive, and live microbes die off over a product’s shelf life. Our two labels show it plainly. 40 mg gives 10 billion CFUs on one, and 10 mg gives 1 billion on the other. Weight does not convert to a count in any fixed way across different strains, so compare CFUs, not milligrams.

You will also see “Daily Value not established” next to both lines. There is no Daily Value for probiotics, so there is no percentage to read.

Step 3: At time of manufacture or through expiration?

Because live cells die off over time, a CFU count is only meaningful if you know when it applies. Labels usually fall into one of three groups:

• Through expiration (or “through the date on the package”): the brand states the count should still be at least the labeled amount on the last day of shelf life, usually only if you store it as directed.
• At time of manufacture: the count when the product was made. By the time you open it, the live count can be lower.
• Not stated: the panel gives a number but no time point.

The Culturelle box, as recorded in the NIH label database in 2021, says “Guaranteed potency through date on box when stored as directed.” Its product page also says the brand measures the number of live probiotics at the expiration date. That is the brand’s statement, and we have not checked it.

The Amazing Grass Supplement Facts image we viewed lists 1 Billion CFU without saying whether that figure is at manufacture or through the date. Check the rest of the package, or ask the brand, if that matters to you. When a label says nothing, do not assume the count holds through expiration.

Step 4: Read the full strain name

A probiotic name has up to three parts: genus, species and strain. The strain is the code or letters at the end.

• Lactobacillus (genus) rhamnosus (species) GG (strain), often shortened to LGG. Culturelle Digestive Daily lists this one strain.
• Bacillus (genus) subtilis (species) DE111 (strain) in Amazing Grass Super Greens.

Two products can share a genus and species and still contain different strains. A label that names the strain tells you exactly which organism is inside, so you can compare products or look the strain up. A label that stops at genus and species, or lists a “probiotic blend” with one total weight, tells you less. Also count the strains: Culturelle is a single-strain product, and many probiotics list several. More strains or a bigger number is not automatically a better choice for you, and a label cannot answer that question.

Step 5: Follow the storage line

Storage is part of the promise. “Through expiration when stored as directed” only holds if you store it the way the label says.

• Culturelle: the label says to store it in a cool, dry place away from direct sunlight, and the capsules come sealed in blisters with a note not to use one if its blister is torn or open. The brand says the capsules do not need refrigeration.
• Other products: some probiotics say “refrigerate” or “keep refrigerated after opening”. If yours does, a pantry shelf is not “as directed”.

Heat and moisture are the usual concerns, so keep any probiotic away from a stove, a dishwasher or a steamy bathroom unless the label says otherwise.

Step 6: Separate the microbes from everything else

Not every line near the probiotic is a probiotic.

• Prebiotic fiber: Culturelle’s panel lists Inulin (Chicory Root Extract) at 200 mg. Inulin is a fiber, not a microbe, and it is not part of the CFU count. If you avoid chicory or inulin, note it.
• Other ingredients: Culturelle lists hydroxypropyl methylcellulose (the capsule), vegetable magnesium stearate and titanium dioxide (color).
• Multi-ingredient products: in Amazing Grass Super Greens the probiotic sits under a greens blend, an antioxidant blend and a fiber blend of organic flax seed and apple pectin. Read the whole panel, not only the CFU line.

Also read the directions and warnings. Culturelle’s label gives directions for ages 12 and up (one capsule daily) and says to inform a healthcare professional before starting any dietary supplement, particularly with a known immune-compromised condition. If you are pregnant, nursing, take medication or have a medical condition, talk to your doctor first.

Quick checklist

• Serving size: one capsule, or more?
• Weight first, then CFUs in parentheses or on a sub-line.
• Compare CFUs, not milligrams.
• Time point: through expiration, at manufacture, or not stated?
• Full strain name, including the strain code.
• Storage: room temperature or refrigerated, and in what packaging?
• Non-microbe ingredients such as inulin, capsule material and colors.
• Directions, age range and warnings.

For more on how supplement brands back up their labels, see our list of third-party tested supplements. Two other label explainers use the same step-by-step format: fish oil labels and vitamin D3 labels.

FAQ

What does CFU mean on a probiotic label?

Colony forming units: a count of microbial cells that are alive and able to grow. FDA’s draft guidance lets brands list CFUs in addition to the required weight, and says the count should include only live microbes.

Why is the probiotic listed in milligrams too?

FDA rules require ingredients on a Supplement Facts panel to be declared by weight. The CFU count is an extra, optional declaration that comes after the weight.

Is a higher CFU count better?

A label cannot tell you that. It tells you how many live cells the brand states, for which strain and at what point in time. Whether any amount suits you is a question for your doctor.

What does “guaranteed through expiration” mean?

The brand states the live count should still meet the labeled amount on the expiration date, usually only if stored as directed. “At time of manufacture” refers to when the product was made, and the live count can drop after that.

Do all probiotics need to be refrigerated?

No. Some are labeled for room temperature, such as Culturelle Digestive Daily, and some say to refrigerate. Follow the storage line on your package.

Is a probiotic in a greens powder labeled the same way?

Yes. In Amazing Grass Super Greens it appears as its own line, Bacillus subtilis DE111 (1 Billion CFU) at 10 mg, with weight and count on the panel like a standalone probiotic.

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.