Peptides and amino acids
A peptide is a short chain of amino acids joined by peptide bonds. Amino acids are also the building blocks of proteins. These terms describe molecular structure; the word “peptide” alone does not tell you what a particular material does or whether it is suitable for an experiment. NHGRI: peptide; NHGRI: amino acids.
For a product comparison, start with the exact compound name and specification. A similar abbreviation is not enough to establish that two materials are equivalent.
In vitro, in vivo and preclinical
- In vitro
- Work performed outside the body in a laboratory setting. NCI definition.
- In vivo
- Work performed within a living body. Always identify the organism in the paper; the term alone does not mean a human study. NCI definition.
- Preclinical research
- Research that can use cells, animals, tissue samples or computer models to explore questions before clinical application. NCATS research spectrum.
Read our guide to preclinical and clinical evidence for the distinction between a model, a study result and a clinical claim.
Terms you will see in study results
- Experimental unit
- The entity independently assigned to a study condition. It may be an animal, a cage or another unit specified by the design.
- Sample size
- The number of experimental units in a group. Repeated measurements on one unit are not automatically additional independent units.
- Outcome measure
- The variable recorded to assess what happened in an experiment.
- Effect size
- A numerical description of a difference between groups or the strength of a relationship.
- Blinding
- Keeping group assignments unknown to people involved in relevant stages of a study, to reduce opportunities for bias.
These summaries draw on the ARRIVE 2.0 explanation and elaboration. Its guidance concerns animal research; the appropriate reporting checklist depends on the study design.
From terminology to product records
On Peptyed, the listed vial amount is a product reference, not an experimental protocol. For a blend, confirm the individual components and their amounts instead of assuming a ratio from the combined amount.
Keep the listing separate from batch-specific evidence. Our batch report guide explains how to review the lot reference, analytical methods and reported results. Use the procurement checklist to record missing information before ordering.