Key takeaways
- Probiotics are live organisms. Prebiotics are what feeds them. Postbiotics are what they produce.
- A postbiotic needs nothing to survive digestion. The active compounds are already made.
- The practical consequences are dose consistency and nothing that has to stay alive.
- Postbiotics are not inherently better. For gut recolonisation a live culture is the right tool.
The three terms, distinguished
The vocabulary is confusing because the words were coined at different times by different fields, and marketing has since blurred them further. The distinction is actually simple.
- Probiotics: live microorganisms intended to confer a benefit when consumed in adequate amounts. Yoghurt cultures, multi-strain capsules, kefir.
- Prebiotics: substrates that feed beneficial organisms already present. Typically fibres: inulin, resistant starch, galacto-oligosaccharides.
- Postbiotics: the compounds produced by microorganisms during fermentation, delivered without the organisms. Metabolites, peptides, cell-wall fractions, enzymes.
Why the format matters
A probiotic has a delivery problem that is rarely stated plainly on the label. The organisms must survive manufacturing, survive the shelf, survive stomach acid, arrive in the intestine viable, and then establish themselves against an incumbent population that is already there and not especially welcoming.
Each of those is a loss point, and the losses are why live-culture products carry cold-chain requirements, colony-forming-unit counts that decline measurably across shelf life, and famously variable individual results.
A postbiotic has no delivery chain to fail. The useful molecules were produced under controlled conditions, separated, and stabilised. Nothing has to survive anything. The dose stated on the bottle is the dose that arrives.
| Criterion | Probiotic (live culture) | Postbiotic (metabolites) |
|---|---|---|
| In the bottle | Live microorganisms | Compounds the organisms produced; no cells |
| Must survive digestion | Yes: shelf, stomach acid, then colonisation | No; the compounds are already made |
| Dose over shelf life | Colony counts decline measurably | Same chemistry batch to batch |
| Handling | Cold chain for viability | Ours: freezer unopened, fridge once open |
| Right tool for | Gut recolonisation after antibiotics | A specific compound at a steady dose over a long protocol |
Postbiotics are not automatically better
This is where we differ from most of the category, which treats "postbiotic" as a straightforward upgrade. It is not. It is a different tool for a different job.
If your goal is rebuilding gut flora after a course of antibiotics, you want live organisms, because repopulating requires something alive to do the repopulating. No postbiotic accomplishes that, and any brand implying otherwise is selling past the evidence.
Where postbiotics have the advantage is anywhere the target is a specific compound rather than a resident population, and anywhere reliability over a long protocol matters more than colonisation.
Fermentation-derived compounds are not new
There is nothing new about the underlying idea, which counts for it rather than against it. Human food cultures have relied on fermentation-derived compounds for millennia: miso, natto, koji, aged cheeses, sourdough, soy sauce. In each case what is valued is substantially what the organisms produced, not the organisms themselves.
What is new is the isolation and characterisation: identifying a specific metabolite fraction, documenting it, and delivering it at a consistent dose. That is an advance in manufacturing and analysis, not in concept.
Where Bacillus F fits
Our product is a postbiotic in the strict sense: the metabolite fraction of the Bacillus F strain, produced under controlled fermentation, separated from the cells, cold-processed into drops. There are no live organisms in the bottle and we say so on every page rather than leave you to work it out.
What follows from the format: no viability decline, the same chemistry batch to batch, and the same potency at day ninety as at day one. Ours is kept in the freezer until opened and in the fridge after, and that is the whole of the handling. For a daily habit meant to run for months, that kind of reliability is usually what decides whether the habit survives.
If a live culture is what you needed, better you hear it here than after you’ve paid.
Choosing a postbiotic supplement: what to check before you pay
The word on the front of the box tells you very little, so read the back. A postbiotic supplement worth money names the organism, says what fraction of its output is in the bottle, and states a dose that does not change over shelf life. For the Bacillus F drops that is 2 ml a day in two 1 ml presses, two 30 ml applicators per 30-day protocol, at $250 a protocol.
Provenance is the second thing to check. The strain behind our preparation was isolated in 2009 and is documented in patent WO2012060729; the strain page lists the deposit and the publications, and the Science page carries the comet-assay panels. If a brand cannot point you to that kind of record, you are buying a word, not a postbiotic supplement.
- Is the organism named, with a strain identifier, or just a genus?
- Is there a live-culture count on the label? If so, it is a probiotic, whatever the marketing says.
- Does the storage instruction match the format? Ours is freezer unopened, fridge once open, and we say why on the FAQ.
- Is the mechanism narrow and stated? Oxidative resilience is ours; read what oxidative stress is before deciding whether that is the lever you want.