Glossary · Pharmacology
Bioavailability
In short
Bioavailability indicates what proportion of an ingested substance reaches the bloodstream unchanged. For an intravenous dose it is 100 percent by definition, for a tablet often considerably less.
Along the way, some is lost: a swallowed substance is not fully absorbed in the gut, is broken down by digestive enzymes or is metabolized in the liver before it reaches the rest of the body. Peptides are mostly digested in the gastrointestinal tract.
Better bioavailability is a common marketing argument, for example for liposomal or micellar forms. But it is only an intermediate step: more in the blood does not automatically mean more effect, and a new form needs its own efficacy data. If a substance is already almost fully absorbed, there is nothing more to gain.
More in the blood is a measurement — not yet a benefit.
Where this comes up in the fact checks
- Liposomal creatine – Creatine monohydrate is already 99 percent absorbed; there is not a single publication on the liposomal form in humans.
- Turmeric – Piperine, micelles and phospholipid complexes are pharmacokinetically very different routes, not all of which have their own efficacy data.
- BPC-157 – Considered acid-stable, which is unusual for a peptide; the mechanism of action comes only from animal studies.
Related terms: Half-life · Peptide · Surrogate marker
Information only, not medical advice. The BK-Score is a subjective assessment according to disclosed rules – not a scientific evaluation. Scoring rules