The phenomenon where a drug is metabolized by the liver before reaching systemic circulation, significantly reducing bioavailability. This is a primary reason most peptides are administered by injection rather than orally.
"First-Pass Metabolism" is filed under Pharmacology in the PeptideAtlas glossary, alongside 29 other terms in that group.
The term applies directly to 2 compound profiles here: Selank (evidence D), Noopept (evidence C). Each profile states the strength of the human evidence rather than only what the compound is claimed to do.
1 other glossary entry refer to this term in their own definition, which is usually the fastest way to see how it is used in practice.
Administration under the tongue where the substance is absorbed through the oral mucosa directly into the bloodstream, partially bypassing first-pass metabolism. Some peptides are explored via this route.
The proportion of a substance that enters the circulation when introduced into the body and is able to have an active effect. Different administration routes affect bioavailability.
The time required for the concentration of a substance in the body to decrease by half. Determines dosing frequency and accumulation patterns.
The study of how a drug moves through the body — absorption, distribution, metabolism, and excretion (ADME).
Compounds where this applies: Selank, Noopept.
Terms that reference this one: Sublingual.
More Pharmacology terms: Bioavailability, Half-Life, Pharmacokinetics, Pharmacodynamics, Receptor Agonist, Receptor Antagonist, Desensitization, Tachyphylaxis, Downregulation, GLP-1 (Glucagon-Like Peptide-1), GIP (Glucose-Dependent Insulinotropic Polypeptide), Glucagon, Amylin, Ghrelin, Growth Hormone Secretagogue (GHS), GHRP (Growth Hormone Releasing Peptide), GHRH (Growth Hormone Releasing Hormone), GHS-R1a (Growth Hormone Secretagogue Receptor), Secretagogue, Melanocortin Receptor.