PeptideX information

Peptide research.
In plain English.

A beginner-friendly glossary of peptide research terms, study types and common scientific measurements.

A quick reference for curious readers

These explanations help you read research and follow discussion. They are not instructions for using a product.

Peptide

A molecule made from amino acids joined by peptide bonds. Peptides have many different roles and properties; the word alone does not describe a product’s effects or suitability.

Amino acid

A building block used to make peptides and proteins.

In vitro

Research carried out outside a living organism, for example in cells or a laboratory preparation.

In vivo

Research carried out in a living organism. Check whether the study involved animals or humans.

Preclinical research

Research conducted before clinical studies, often using laboratory preparations or animal models. It cannot on its own establish an effect in people.

Clinical study

Research involving human participants. Its design, size, population and measured outcomes matter when interpreting the result.

Randomised controlled trial

A study in which participants are assigned by chance to groups receiving different interventions or a comparison. Randomisation can help reduce bias.

Placebo

A comparison intervention designed to resemble the treatment being studied without its specific active component.

Peer review

Assessment of research by other specialists before publication. It is a quality-control process, not a guarantee that a finding is correct.

Systematic review

A structured review that searches for, selects and assesses research addressing a defined question.

Meta-analysis

A statistical method for combining results from multiple studies. Its reliability depends on the studies included and how they are combined.

Mechanism of action

An explanation of how a substance produces an effect. A proposed mechanism is different from evidence of a meaningful benefit in people.

Bioavailability

The extent and rate at which a substance reaches the circulation. Findings can differ by preparation and route.

Half-life

The time taken for a measured amount or concentration to fall by half under specified conditions. It is not, by itself, a dosing instruction.

Concentration

The amount of a substance in a specified volume, such as milligrams per millilitre. It is different from the total amount in a container.

mg, micrograms and ml

mg means milligram; a microgram is one thousandth of a milligram. ml means millilitre, a unit of volume. Mass and volume are different measurements.

Research use only

A stated intended use for research. It does not itself demonstrate regulatory approval, safety or suitability for human use.

When you open a study

Start with four questions: who or what was studied, what was compared, what was actually measured, and what limitations do the authors report? Look for the original publication rather than relying on a screenshot or a headline.

Useful starting points: PubMed for published research, ClinicalTrials.gov for study registrations and the Cochrane evidence library.

Prepared by the PeptideX team as a plain-English community reference. For website questions, contact PeptideX.

Last updated: 9 November 2026