Postbiotics
The newest member of the 'biotics' family, formally defined only in 2021 — inanimate microorganisms and their metabolites, which don't need the bacteria to survive in order to work.
Number of studies
1
Safety
High
Time to effects
There is not yet enough clinical data to precisely determine a typical time to effects in humans.
Who it's for
Table of contents
TL;DR
The newest member of the 'biotics' family, formally defined only in 2021 — inanimate microorganisms and their metabolites, which don't need the bacteria to survive in order to work.
- →Don't require maintaining bacterial viability, which improves stability during storage
- →May modulate immune response in the gut through recognized cellular fragments
- →Provide an alternative for people who tolerate classic probiotics poorly
| Compound type | Inanimate microorganisms and their metabolites/cellular components |
|---|---|
| Level of evidence | Preliminary — the field was only formally defined in 2021 |
| Target group | People who tolerate classic probiotics with live bacteria poorly |
| Key difference from probiotics | Don't require the bacteria to survive in order to work |
| Status | Dietary supplement category, formally systematized by ISAPP in 2021 |
Understand
Overview
Postbiotics are a category, formally defined in 2021 by the International Scientific Association of Probiotics and Prebiotics (ISAPP), of preparations containing inanimate microorganisms or their components (cell fragments, metabolites) that confer a health benefit on the host. Unlike probiotics, postbiotics don't require the bacteria to survive passage through the digestive tract in a live form — which removes some of the stability and survivability challenges associated with classic probiotics.
The official ISAPP position statement, published in Nature Reviews Gastroenterology & Hepatology, organized previously imprecisely used terminology and clearly distinguished postbiotics from related but distinct concepts — dead probiotics without proven health benefits, or purified bacterial metabolites (like butyrate) sold separately. This is still a relatively young, fast-growing area of research, with fewer human clinical studies than well-established probiotics.
Who might actually find this useful? People for whom classic probiotics with live bacteria are poorly tolerated or lose activity during storage and transport, since postbiotics don't require maintaining microorganism viability. Given the still-early stage of research, it's worth treating them as a promising but less well-established direction than classic probiotics and prebiotics.
Mechanism of action
Postbiotics can act through several mechanisms at once: fragments of the cell walls of inanimate bacteria (e.g., lipoteichoic acid) can be recognized by immune-system receptors in the gut, modulating local and systemic immune response without requiring live bacteria to colonize the gut. Some postbiotics also directly contain bacterial metabolites, such as short-chain fatty acids or bacteriocins, exerting a physiological effect immediately upon delivery, without a fermentation step by the host's microbiome.
Because postbiotics don't need to survive in a live form, they are potentially more stable during storage and transport than classic probiotics, whose effectiveness strongly depends on maintaining an adequate number of live colony-forming units (CFU) until consumption — a practical, technological advantage independent of the underlying biological mechanism of action.
Recognition by immune receptors
Fragments of the cell walls of inanimate bacteria can modulate immune response in the gut.
Direct delivery of metabolites
Some postbiotics contain ready-made metabolites, like short-chain fatty acids, acting without a fermentation step.
Higher technological stability
The lack of a bacterial-survival requirement makes storage and transport easier compared to classic probiotics.
Evidence: early-stage — based on 1 study in this database.
Benefits
Common myths
MythPostbiotics are just a marketing name for dead, ineffective probiotics.
FactThe formal ISAPP definition explicitly requires that a postbiotic confer a proven health benefit — this distinguishes the category from ordinary, inactive dead bacteria with no demonstrated effect.
MythPostbiotics are better than probiotics because they're newer.
Fact'Newer' doesn't mean 'better studied' — classic probiotics have a considerably longer history of clinical research than the still-nascent postbiotics category.
Practice
Frequently asked questions
Probiotics are live microorganisms that must survive the trip through the digestive tract to work, while postbiotics are inanimate and don't require maintaining viability to confer a health benefit.
No — the postbiotics category was only formally defined in 2021 and has considerably fewer human clinical studies than well-established probiotics.
Yes, when delivered directly as a supplement — it's an example of a bacterial metabolite classified as a postbiotic.
Dosage & timing
Typical dose
Depends on the specific preparation and its ingredients — no single universal dosing standard
Form
Capsules, powders, or liquids containing inanimate bacteria or their metabolites
Given the young age of this category, it's worth choosing preparations with a clearly described, specific composition and, where possible, a reference to clinical studies.
What to combine with
Good combinations
Probiotics — Postbiotics and probiotics are sometimes used interchangeably or together, depending on individual tolerance and goal
Safety
Side effects & contraindications
Possible side effects
Limited data on side effects due to the early stage of clinical research
Contraindications
No significant contraindications at typical doses.
Is it worth taking?
Who it's for
- People who tolerate classic probiotics with live bacteria poorly
- People interested in newer directions in microbiome research
Not for
- No significant contraindications at typical doses.
Evidence
Worth knowing
The term 'postbiotic' was only formally defined by the International Scientific Association of Probiotics and Prebiotics in 2021.
Butyrate, a fermentation product of prebiotic fiber, is sometimes also classified as a type of postbiotic when delivered directly as a supplement.
Studies
A postbiotic is a preparation of inanimate microorganisms or their components that confers a health benefit on the host — this definition deliberately distinguishes the category from dead probiotics without proven benefit.
Salminen S, et al., Nature Reviews Gastroenterology & Hepatology, 2021 (ISAPP position statement)
The International Scientific Association of Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of postbiotics
Early-stage evidenceSalminen S, Collado MC, Endo A, et al. · Nature Reviews Gastroenterology & Hepatology · 2021
The official ISAPP consensus statement formally defining the term 'postbiotic' and organizing terminology in this area.
View studySources & bibliography
Citations are illustrative for this demo version and require full bibliographic verification by the editorial team before production publication.
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About the authors of this entry
Author
dr Anna KowalczykEditor-in-Chief, Molecular Biology
Anna oversees the editorial process and scientific review of every publication in the knowledge base. She previously researched autophagy and mitochondrial biology.
50 publications on this site
Medical review
Julia WiśniewskaEditor, Neurohacking & Sleep
Julia writes about nootropics, chronobiology and recovery protocols.
45 publications on this site
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Comments (2)
- KW
Kasia W. 2 weeks ago
Very clearly explained, especially the interactions section — I hadn't seen it laid out this well anywhere else.
- MT
Marek T. a month ago
Are you planning to update this with the newest study from this year? I saw an interesting meta-analysis.