Education
Peptide Glossary: Common Terms Explained
A quick-reference glossary of terms that commonly appear across peptide, GLP-1, and TRT educational material.
Reviewed by GoodDaily Editorial Team · Published 2026-08-10
Why a glossary is useful
Peptide, GLP-1, and TRT reference material tends to reuse the same handful of technical terms. This page collects plain-English definitions in one place so they are easy to look up.
Core terms
- Peptide: a short chain of amino acids, smaller than a full protein.
- GLP-1: glucagon-like peptide-1, a naturally occurring gut hormone; see GLP-1 Receptor Agonists Explained.
- TRT: testosterone replacement therapy, a prescribed hormone treatment; see TRT Basics.
- Half-life: the time for the amount of a substance in the body to fall by half; see What Is Peptide Half-Life?.
- Reconstitution: adding a diluent to a freeze-dried substance to return it to liquid form; see Reconstitution Basics.
- Concentration (mg/mL): the strength of a solution, calculated from the amount of substance and the volume of liquid; see What Is Concentration Math?.
- Subcutaneous (subQ): the fat layer just under the skin; see SubQ vs IM.
- Intramuscular (IM): muscle tissue, deeper than the subcutaneous layer.
- Certificate of analysis (COA): a document reporting lab test results for a product; see Evaluating Sourcing and Quality.
- Cold chain: unbroken temperature-controlled storage and transport; see Storage and Cold Chain Basics.
How to use this glossary
These definitions are general and educational. They describe how terms are commonly used in reference material, not how any specific product should be used, stored, dosed, or administered. For anything specific to a product or a person’s health, consult a licensed healthcare professional.
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