Prebiotics vs Probiotics

The Core Difference

Probiotics are live bacteria you ingest. They are almost always transient—they do a job as they pass through, but they don't move in permanently.

Prebiotics are selective fertilizers (usually specialized fibers) that feed the beneficial bacteria already native to your gut.

The Case for Prebiotics

Your native microbiome is uniquely adapted to you. It's incredibly difficult to introduce a foreign strain and have it outcompete established colonies. However, if you consume prebiotics like Galacto-oligosaccharides (GOS) or Inulin, you can selectively multiply your own native Bifidobacteria populations by magnitudes far greater than you could ever consume in a pill.

Type	Examples	Primary Function
Probiotic	LGG, 35624	Transient clinical effects (immune modulation, barrier support)
Prebiotic	GOS, FOS, Inulin, PHGG	Feed endogenous flora, increase SCFA (butyrate) production

What about Synbiotics?

A synbiotic combines both. However, a true synbiotic must contain enough prebiotic to matter. Many probiotics include 50mg of inulin and call themselves a synbiotic—this is marketing fairy dust. An effective prebiotic dose is typically measured in grams (e.g., 3-5g), not milligrams.