Postbiotics are the beneficial compounds produced when probiotic bacteria ferment fibre in your gut — plus the useful components of the bacteria themselves. In 2021 the International Scientific Association for Probiotics and Prebiotics (ISAPP) defined a postbiotic as a "preparation of inanimate microorganisms and/or their components that confers a health benefit." In short: prebiotics feed the bacteria, probiotics are the bacteria, and postbiotics are what they produce.
Postbiotics are the newest of the three to get attention, and search interest has climbed sharply as more formulas start including them. Here's what they actually are, how they differ from the terms they're often confused with, and what the evidence supports — in plain English.
What are postbiotics, exactly?
Postbiotics are the by-products and components left after probiotic bacteria do their work. When good bacteria ferment the fibre you eat, they produce beneficial compounds — most notably short-chain fatty acids such as butyrate — along with other molecules and useful fragments of the bacteria themselves. It's these end-products, not live organisms, that make up a postbiotic. Because they're not live, they tend to be more stable and don't need to survive your stomach acid the way live probiotics do.
Prebiotics vs probiotics vs postbiotics: the simple difference
The three sound alike and get muddled constantly. The easiest way to hold them apart:
| Term | What it is | Everyday analogy |
|---|---|---|
| Prebiotics | Fibres that feed your good bacteria | The food / fertiliser |
| Probiotics | The live beneficial bacteria themselves | The plants |
| Postbiotics | The beneficial compounds the bacteria produce | The harvest |
A well-rounded gut-support formula often includes all three: a prebiotic to feed the bacteria, a probiotic to add them, and a postbiotic to deliver the useful end-products directly.
What do postbiotics do? What the research shows
Research into postbiotics is younger than for pre- and probiotics, but it's growing. Short-chain fatty acids like butyrate are a key energy source for the cells lining your colon and are studied for their role in supporting the gut barrier (the lining that keeps your gut environment in order). Postbiotics are also being researched for their interaction with the immune system, much of which sits around the gut. As always with supplements, the honest framing is "studied for a supportive role," not "cures" anything.
Why postbiotics matter more after 40
As covered in how the gut changes after 40, the microbiome tends to become less diverse around menopause, and digestion can feel less predictable. A less diverse microbiome may produce fewer of these beneficial by-products on its own — which is part of why formulas that supply a postbiotic directly, alongside a probiotic and prebiotic, are increasingly popular for this stage of life. It's a way of supporting the gut environment rather than relying on the microbiome to do everything unaided.
Are postbiotics safe?
For most healthy adults, postbiotics from foods and reputable supplements are generally well tolerated — and because they're not live organisms, they're stable and don't carry the "will they survive to my gut?" question that live probiotics do. If you're pregnant, immunocompromised, or managing a health condition, check with your GP or a registered dietitian before starting any new supplement.
How to get more postbiotics
- Feed your own bacteria. Eating plenty of varied plant fibre gives your gut bacteria the raw material to make postbiotics themselves.
- Eat fermented foods. Foods like kombucha, yoghurt, kefir and sauerkraut contain a mix of live cultures and their by-products.
- Choose a complete formula. A supplement that combines a prebiotic, probiotic and postbiotic covers all three roles in one daily step.
All three in one daily gummy — pre + pro + postbiotic.
GutBio Probiotic Kombucha Gummies combine a prebiotic, live probiotic cultures and a postbiotic, plus slippery elm and dandelion root — designed to support digestion and everyday gut comfort for women over 40.* One gummy a day, 60-day buyback guarantee.
Explore GutBio →Frequently asked questions
What are postbiotics in simple terms?
They're the beneficial compounds your good gut bacteria produce when they ferment fibre — such as short-chain fatty acids like butyrate — plus useful components of the bacteria themselves. Prebiotics feed the bacteria, probiotics are the bacteria, and postbiotics are what they make.
What is the difference between probiotics and postbiotics?
Probiotics are live beneficial bacteria you add to your gut. Postbiotics are the non-living, beneficial end-products those bacteria create. Because postbiotics aren't alive, they're more stable and don't need to survive stomach acid to be useful.
Are postbiotics better than probiotics?
Neither is "better" — they do different jobs, and they work well together. A probiotic adds bacteria, a prebiotic feeds them, and a postbiotic supplies the beneficial compounds directly. Formulas that include all three tend to be more complete than any one alone.
Do postbiotics help with bloating?
Postbiotics are studied for supporting the gut lining and a balanced gut environment, which is linked to more comfortable digestion. No supplement cures bloating, but supporting the gut environment — with postbiotics as one part of a complete routine — is a sensible, evidence-informed approach.
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Sources & further reading
- Salminen S, et al. "The International Scientific Association of Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of postbiotics." Nature Reviews Gastroenterology & Hepatology (2021).
- General reference on short-chain fatty acids and gut health: peer-reviewed reviews via PubMed/PMC.
*These statements have not been evaluated by the Food and Drug Administration. This product is a food supplement and is not intended to diagnose, treat, cure, or prevent any disease. This article is educational and not a substitute for medical advice; speak to your GP or a registered dietitian about your own symptoms. Individual results may vary.