Pillar · Glossary
Peptide Glossary: Research Terminology Explained
Peptide literature is dense with terms that carry precise meanings. This glossary defines the vocabulary used across the site so that every other page can be read accurately, and links each definition into the hub where the concept matters most.
Evidence position
Established clinical evidence
Research evidence, established clinical evidence and regulatory approval are three different things. This page distinguishes them throughout and does not present research compounds as approved treatments.
Core pharmacology terms
Agonist — a molecule that binds a receptor and activates it. Antagonist — binds and blocks activation. Partial agonist — produces a submaximal response even at receptor saturation. Selectivity — the degree to which a molecule acts on its intended receptor rather than related ones. Potency — the concentration required to produce an effect, which is not the same as how large that effect can be.
Pharmacokinetic terms
Half-life — the time for circulating concentration to fall by half. Bioavailability — the proportion of an administered amount that reaches systemic circulation, which for unmodified oral peptides is close to zero. Clearance — the rate at which a compound is removed. Cmax and Tmax — peak concentration and the time it occurs.
Research method terms
In vitro — in cells or isolated systems. In vivo — in a living organism. Randomised controlled trial — participants allocated by chance to intervention or comparator. Double-blind — neither participants nor assessors know allocation. Surrogate endpoint — a measurement standing in for the outcome that matters. Meta-analysis — statistical pooling of multiple studies.
Quality and safety terms
HPLC — chromatographic purity analysis. Mass spectrometry — confirms molecular weight and therefore identity. Endotoxin — bacterial cell-wall contaminant that survives sterile filtration. Lyophilised — freeze-dried for stability. Certificate of analysis — a batch document reporting analytical results, only as reliable as the laboratory that produced it.
Key takeaways
- Peptide literature is dense with terms that carry precise meanings. This glossary defines the vocabulary used across the site so that every other page can be read accurately, and links each definition into the hub where the concept matters most.
- Overall evidence position for this topic: established clinical evidence.
- Findings in cells or animals are hypotheses about humans, never demonstrations in humans.
- Nothing on this page is medical advice, a protocol, or a dosing recommendation.
Frequently asked questions
What does 'in vitro' mean?
Research performed in cells or isolated biological systems outside a living organism. In-vitro findings do not establish effects in animals or people.
What is a secretagogue?
A compound that stimulates the body to secrete a substance of its own — for example, a growth hormone secretagogue prompts pituitary release of growth hormone.
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Related research hubs
Peptide Science
How peptides are built, how they signal, how they are synthesised and how they are studied — the foundational science behind every other topic on this site.
Peptide Research & Clinical Trials
How peptide research is conducted and graded — trial phases, endpoints, evidence hierarchy, and how to read a peptide study without over-reading it.
Peptide Safety
What is actually known about peptide safety — immunogenicity, contamination, unknown long-term profiles, and why absence of reported harm is not evidence of safety.
About this page
Written and reviewed by the Peptide Intel Hub Editorial Team. Last reviewed 8 September 2026.
Scientific disclaimer: this page is educational and does not constitute medical advice. Research compounds referenced here are not approved treatments. See our research disclaimer.