Prebiotic, probiotic or postbiotic? How to check each word on a gummy label
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Gummy labels now use three similar words: prebiotic, probiotic and postbiotic. Some products claim all three at once. Each word has a formal scientific definition, and each should appear on the Supplement Facts panel in a different unit. Knowing which unit goes with which word is the fastest way to tell a substantial product from a decorative one.
This article is a label checklist. For the science behind each term, see our probiotics, prebiotics and postbiotics guide.
The three words in one table
| Probiotic | Prebiotic | Postbiotic | |
|---|---|---|---|
| What it is | Live microorganisms | A substance your gut microbes feed on | Inactivated microorganisms or their components |
| Alive? | Yes, it must be | Not applicable | No, by definition |
| Unit to look for | CFU, usually billions | Grams | Milligrams or cell count, with a strain name |
| Typical label names | Bacillus coagulans, Bacillus subtilis, Lactobacillus, Bifidobacterium | Inulin, FOS, GOS, XOS | “Heat-treated” or “heat-killed” plus a strain |
| Common weak point in gummies | No CFU count | Amount far below studied doses | Strain not named |
All three definitions come from expert panels of the International Scientific Association for Probiotics and Prebiotics, published in 2014, 2017 and 2021. All three end with the same condition: the ingredient must provide a health benefit. A name on a label does not satisfy that. Evidence for the specific ingredient at the amount provided does.
Checking the probiotic line
What the definition requires
Live microorganisms, in adequate amounts, with a demonstrated benefit. On a label that translates into three things to find.
- A strain code. Genus, species and strain, for example Bacillus subtilis DE111. Benefits are strain-specific, so the code is what connects a product to research.
- A CFU count. Colony forming units measure live cells. Research doses are given in CFU.
- The words “at expiration” or similar. Live counts decline in storage.
Red flags
- “Probiotic blend” with no strains listed.
- The probiotic given only in milligrams.
- A count “at time of manufacture”.
- A strain that does not form spores in a gummy with no explanation of how it survives. See do probiotic gummies survive.
Checking the prebiotic line
What the definition requires
A prebiotic is a substance that microbes in the body use selectively, with a resulting health benefit. In practice most are particular kinds of fiber: inulin, fructooligosaccharides (FOS), galactooligosaccharides (GOS) and xylooligosaccharides (XOS). Not every fiber is a prebiotic, and the definition is not limited to fiber.
The unit is grams
This is where gummies struggle. Studies of prebiotic fibers generally use gram amounts: typically 3 g or more a day for inulin and FOS, and around 1 g to 4 g a day for XOS, which is active at lower amounts than most. A gummy weighs a few grams in total, and most of that is sweetener and pectin. There is little room for grams of fiber.
| Label amount | How to read it |
|---|---|
| 3 g or more of inulin or FOS per serving | In the range used in studies. Rare in gummies; more common in fiber gummies sold as such |
| 1 g or more of XOS | In the studied range |
| 50 mg to 500 mg of any prebiotic | Well below studied amounts. Present, but unlikely to act as a prebiotic dose |
| Inside a proprietary blend | Amount unknown |
Remember that 1 g is 1,000 mg. A label listing 50 mg of a prebiotic is listing one twentieth of a gram. Our article on proprietary blends explains why hidden amounts matter.
A practical note
You already eat prebiotics. Onions, garlic, leeks, asparagus, bananas, oats and beans all contain them. A serving of beans supplies more prebiotic fiber than most gummies. Prebiotic fibers in gram amounts can also cause gas and bloating, especially at first.
Checking the postbiotic line
What the definition requires
The 2021 definition describes a postbiotic as a preparation of inanimate microorganisms, their components, or both, that provides a health benefit. In plain terms, it is made from microbes that have been deliberately inactivated, usually by heat. The cells are not alive and are not meant to be.
The definition is narrower than popular use. Purified substances produced by microbes, such as a vitamin or an isolated acid, do not count as postbiotics on their own under this definition.
What to look for
- The source strain, named with its code. As with probiotics, evidence belongs to a particular strain and preparation.
- The word “heat-treated”, “heat-killed” or “inactivated”.
- An amount, in milligrams or as a cell count.
Postbiotics suit gummies well for one reason: nothing has to be kept alive. Heat in manufacturing and time on the shelf are not threats. The limitation is the research, which is newer and smaller than for probiotics and is specific to each preparation.
“3-in-1” products
A product that combines a probiotic with a prebiotic is often called a synbiotic. Adding a postbiotic gives the “pre, pro and post” claim. There is nothing wrong with the idea. Check each ingredient on its own line, with its own unit, exactly as above. The combination does not lower the bar for any of them.
A worked example
The Supplement Facts panel for Goli Probiotic+ Gummies lists three ingredients per three-gummy serving.
| Line on the label | Type | Check |
|---|---|---|
| Bacillus subtilis DE111, 10 mg | Probiotic | Strain named, and it is a spore-former suited to gummies. Given in milligrams; no CFU count on the page we read |
| Heat-treated Lactobacillus paracasei MCC1849, 20 mg | Postbiotic | Source strain named and described as heat-treated. Amount given in milligrams |
| Xylooligosaccharides, 50 mg | Prebiotic | A recognized prebiotic. The amount is below the gram-level amounts used in studies |
That reading shows the method. All three types are present and named, which is more than many labels offer. The open questions are the CFU count and the size of the prebiotic amount. Statements about what the product does for digestion are Goli’s own, and our review sets out which line each one relates to.
Sugar, the fourth thing to check
It is easy to forget on a gut health product. A probiotic gummy serving often contains 2 g to 5 g of sugar. If you take several different gummies a day, add them up. See added sugar in gummies.
Which do you need?
There is no rule that a healthy adult needs any of the three as a supplement. A varied diet with plenty of plants supplies prebiotic fiber. Fermented foods such as yogurt and kefir with live cultures supply live microbes, although not all of those have been tested as probiotics. Supplements make most sense when there is a specific reason and a specific strain or ingredient with evidence for it. If a doctor has recommended one, buy what was recommended.
People with a weakened immune system or a serious illness should speak to a doctor before taking live probiotics. Postbiotics and prebiotics do not carry that particular concern, since they contain no live organisms, but ask anyway if you have a medical condition.
The background on all three terms is in the probiotics, prebiotics and postbiotics guide. Our Goli Probiotic+ Gummies review reads one label in full, and related reviews are on the gut and digestion gummies page.
The short version
- Probiotic: live microbes. Look for a strain code and CFU through expiration.
- Prebiotic: food for your gut microbes. Look for grams, not a few milligrams.
- Postbiotic: inactivated microbes. Look for the source strain and “heat-treated”.
- All three definitions require a demonstrated benefit.
- A “3-in-1” claim is three separate checks.
- Count the sugar too.
Common questions
What is the difference between a prebiotic and a probiotic?
A probiotic is a live microorganism. A prebiotic is a substance, usually a type of fiber, that microbes already in your gut feed on.
What is a postbiotic?
A preparation of deliberately inactivated microorganisms or their components that provides a health benefit. The cells are not alive.
How much prebiotic should a gummy have?
Studies generally used gram amounts: about 3 g or more for inulin and FOS, and around 1 g to 4 g for XOS. Many gummies contain far less.
Is a postbiotic better than a probiotic in a gummy?
It is more stable, because nothing has to stay alive. Its evidence is newer and specific to each preparation.
What does synbiotic mean?
A product that combines a probiotic with a prebiotic.
Should the probiotic be listed in mg or CFU?
CFU. That is the unit research uses, and milligrams cannot be compared with it.
Sources
- Hill C, et al. The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nat Rev Gastroenterol Hepatol. 2014.
- Gibson GR, et al. The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of prebiotics. Nat Rev Gastroenterol Hepatol. 2017.
- Salminen S, et al. The International Scientific Association of Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of postbiotics. Nat Rev Gastroenterol Hepatol. 2021.
- Cutting SM. Bacillus probiotics. Food Microbiol. 2011.
- Freedman KE, et al. Examining the gastrointestinal and immunomodulatory effects of the novel probiotic Bacillus subtilis DE111. Int J Mol Sci. 2021.
- NIH National Center for Complementary and Integrative Health. Probiotics: usefulness and safety.
- NIH Office of Dietary Supplements. Probiotics: fact sheet for health professionals.
These statements have not been evaluated by the Food and Drug Administration. Products discussed here are not intended to diagnose, treat, cure or prevent any disease. This page is not medical advice. It is written for adults 18 and over.