1Start here
What Are Peptides, and What Do They Do?
Heard about peptides? Learn what peptides are, what they do, and how they differ from steroids and proteins in this illustrated beginner’s guide.
Read guide →Research Peptides. Pure Purpose.
Research Library
Heard about peptides and want to understand the science? Start with clear explanations, simple illustrations, and sources you can explore for yourself.
Peptide basics
Follow these guides in order to build on the basics, or choose the question that brought you here.
2Peptide basics
Peptides vs. Proteins vs. Amino Acids: What Is the Difference?
See how amino acids, peptides, and proteins fit together, with a simple comparison, an illustrated chain, and answers to common questions about the differences.
Read guide →3Peptide basics
Types of Peptides: A Beginner’s Guide
What are the different types of peptides? See how length, linear or cyclic connections, and biological role describe them in this illustrated beginner’s guide.
Read guide →4Peptide basics
Natural vs. Synthetic Peptides: What’s the Difference?
A naturally occurring peptide can also be made synthetically. Learn how origin, chemical structure, and sample testing differ—and why the labels can overlap.
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More from the library
Understanding laboratory reports
What Does 99% Peptide Purity Actually Mean?
Understand peptide purity percentages with a worked example: how peak areas are calculated, what overlapping peaks can hide, and why purity differs from quantity.
Read article →Research literacy
In Vitro vs. In Vivo: What Do Peptide Studies Actually Show?
What is the difference between in vitro and in vivo peptide studies? Compare cell and whole-organism experiments, with a plant-peptide example and reading guide.
Read article →Understanding laboratory reports
How to Read a Peptide Certificate of Analysis
Learn to check a peptide Certificate of Analysis: sample and lot details, identity, chromatographic purity, measured quantity and the limits of each result.
Read article →Molecular science
Retatrutide Explained: One Peptide, Three Receptors
What is retatrutide? Explore its modified peptide structure, three receptor targets, cellular signaling and the findings of in vitro studies.
Read article →Molecular science
Tirzepatide Explained: One Peptide, Two Receptors
What is tirzepatide? Explore its modified peptide structure, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor activity, cell signaling and findings from in vitro research.
Read article →Molecular science
Semaglutide Explained: Structure and GLP-1 Receptor Signaling
Explore semaglutide’s peptide structure, GLP-1 receptor signaling and albumin binding, with diagrams and a guide to reading an original laboratory experiment.
Read article →Molecular science
Semaglutide vs. Tirzepatide vs. Retatrutide
Compare semaglutide, tirzepatide and retatrutide by receptor targets, peptide structure and laboratory findings, with diagrams and a side-by-side table.
Read article →Research literacy
How to Find and Evaluate Peptide Research Papers
Find in vitro and non-human peptide research papers with PubMed and Google Scholar. Assess methods, controls, sample size, and study quality with a checklist.
Read article →