For research purposes only. Not for human consumption. This article is educational and references published laboratory research; it is not medical advice and does not describe an approved use of any compound.
Short answer
GLP-1 and GIP are incretin receptors studied in metabolic research. A COA, or certificate of analysis, is the batch document that records identity, purity and peptide content. Reconstitution is the step where a lyophilised powder is dissolved in a solvent such as bacteriostatic water before laboratory use. The sections below define these and the other terms used across our research guides. Material supplied by Vitality Peps is for in vitro laboratory research only.
Peptide research listings and batch documents carry a dense vocabulary. This glossary defines the terms that appear most often across our guides and product pages, grouped into receptor and signalling language, documentation and analysis language, and laboratory handling language. Each definition is descriptive only and describes how a term is used in published research and in supplier paperwork.
How to use this glossary
Terms are grouped by where you meet them. Receptor and signalling terms appear in compound descriptions and in trial literature. Documentation and analysis terms appear on batch paperwork. Handling terms appear on storage labels and in laboratory procedure notes. Unit terms appear whenever a concentration is calculated.
Definitions here describe what a word means, not what a compound does in a person. Where a term connects to a longer article, the relevant guide is linked from that section.
Receptor and signalling terms
These terms describe what a compound binds to and how that interaction is characterised in published research.
| Term | Definition |
|---|---|
| GLP-1 | Glucagon-like peptide-1, an incretin hormone released after nutrient intake. Usually discussed as a receptor target in metabolic research. |
| GIP | Glucose dependent insulinotropic polypeptide, the second incretin hormone, acting on its own receptor and associated with adipose tissue effects. |
| Glucagon receptor | A receptor engaged by the hormone glucagon. In preclinical work its activation was observed to raise hepatic lipid oxidation and energy expenditure. |
| Agonist | A compound that binds a receptor and activates it, producing a response similar to the natural signalling molecule. |
| Dual or triple agonist | A single molecule engineered to activate two or three receptors at once, for example GLP-1 and GIP, or GLP-1, GIP and glucagon. |
| Analogue | A synthetic molecule closely based on a natural sequence, modified to change stability, receptor affinity or duration. |
| Secretagogue | A compound that prompts the release of a hormone, for example growth hormone secretagogues studied alongside GHRH analogues. |
| GHRH | Growth hormone releasing hormone, the upstream signal studied by tesamorelin and CJC-1295 research. |
| DPP-4 | Dipeptidyl peptidase-4, the enzyme that degrades native incretins. Resistance to it is a common design goal in analogues. |
| Half-life | The time for the plasma concentration of a compound to fall by half. Longer half-lives underlie weekly rather than daily dosing schedules in trials. |
Documentation and analysis terms
These terms appear on the paperwork that accompanies a lot. The guide to reading a peptide COA works through a full document field by field.
| Term | Definition |
|---|---|
| COA | Certificate of analysis. The batch level report recording identity, methods, purity, peptide content and date of analysis for one lot. |
| Lot or batch number | The identifier tying a specific vial to the analysis that was run on it. Documentation without a matching lot number cannot be verified. |
| HPLC | High performance liquid chromatography, the separation method most often used to quantify purity as a percentage of peak area. |
| Mass spectrometry | An identity method that measures molecular mass, confirming that the material matches the expected sequence. |
| Purity | The proportion of peptide material that is the target sequence rather than related impurities, typically reported from HPLC. |
| Net peptide content | The proportion of total vial mass that is peptide rather than water, salts and counterions. |
| TFA salt | Trifluoroacetate, a counterion left over from purification. It contributes to vial mass and is one reason peptide content is below 100%. |
| Appearance | A visual specification such as white to off-white lyophilised powder, used as a first check against the document. |
Handling and storage terms
These terms describe the physical state of the material and how it is kept. The storage guide covers temperatures and shelf life in detail.
| Term | Definition |
|---|---|
| Lyophilised | Freeze dried. Solvent removed under vacuum, leaving a dry cake or powder that stores more stably than a solution. |
| Reconstitution | Returning a lyophilised powder to solution by adding a measured volume of solvent. |
| Bacteriostatic water | Sterile water with a small proportion of benzyl alcohol, which inhibits bacterial growth and allows repeated access in laboratory work. |
| Sterile water | Water for injection with no preservative, used where a single access preparation is required. |
| Aliquot | A measured portion of a solution divided out into a separate container, used to avoid repeatedly accessing one stock. |
| Freeze and thaw cycle | One round of freezing and warming a solution. Repeated cycles were associated with peptide degradation in stability research. |
| Cold chain | Keeping material within a defined temperature range from dispatch to arrival, usually 2 to 8 degrees Celsius for peptides in solution. |
| In vitro | Work carried out in a controlled laboratory setting such as cell culture, rather than in a living organism. |
Units and concentration
- mg: milligram, one thousandth of a gram. The mass stated on a vial label refers to the peptide, not the total contents.
- mcg: microgram, one thousandth of a milligram. Commonly used where working solutions are dilute.
- mL: millilitre, the volume unit used for solvent added at reconstitution.
- Concentration: mass divided by volume, for example 10 mg in 2 mL gives 5 mg per mL. The reconstitution calculator performs the arithmetic.
- IU: international unit, an activity based unit used for some biological preparations. It does not convert to milligrams by a single fixed factor across compounds.
Compound shorthand you will meet
- BPC-157: a synthetic pentadecapeptide sequence studied in tissue repair research. See the BPC-157 overview.
- TB-500: a synthetic fragment related to thymosin beta-4, studied alongside BPC-157. See BPC-157 vs TB-500.
- GHK-Cu and AHK-Cu: copper binding tripeptides studied in skin and matrix research. See GHK-Cu vs AHK-Cu.
- CJC-1295 and ipamorelin: a GHRH analogue and a growth hormone secretagogue often discussed together. See CJC-1295 vs ipamorelin.
- Semax and Selank: short peptides of Russian origin studied in cognitive and anxiolytic research. See Semax vs Selank.
- Incretin agonists: semaglutide, tirzepatide and retatrutide, compared in the three way incretin comparison.
Sourcing terms
- Research grade: material synthesised for laboratory investigation and documented by a batch report. Not manufactured or authorised as a medicine.
- Pharmaceutical grade: material manufactured under GMP conditions, authorised by a regulator and dispensed on prescription.
- GMP: good manufacturing practice, the regulated quality framework applied to medicinal products.
- HS code: the customs tariff classification used on shipping paperwork for a consignment.
- EU dispatch: shipment originating inside the European Union, which avoids third country customs handling for EU destinations. See the European buyer's checklist.
Research use only
Every compound named in this glossary and supplied by Vitality Peps is for in vitro laboratory research only. Nothing here is a medicine, a supplement, dosing guidance or a recommendation for human or veterinary use. All material remains subject to the regulations of your jurisdiction.
Frequently asked questions
What does GLP-1 stand for?
GLP-1 stands for glucagon-like peptide-1, an incretin hormone released by the intestine after nutrient intake. In research it is most often discussed as a receptor target: a GLP-1 receptor agonist is a compound that binds and activates that receptor, which in published studies was associated with delayed gastric emptying, glucose dependent insulin release and reduced food intake.
What is GIP and how does it differ from GLP-1?
GIP stands for glucose dependent insulinotropic polypeptide, the second major incretin hormone. It acts on a different receptor from GLP-1. In published research GIP receptor activation was observed to influence adipose tissue metabolism and energy expenditure, effects that GLP-1 receptor activation alone does not produce. Compounds that engage both receptors are described as dual agonists.
What is a COA for a research peptide?
A COA, or certificate of analysis, is the batch level document a supplier issues for a specific lot. It normally records the compound identity, the lot number, the analytical methods used, the measured purity, the peptide content and the date of analysis. Our guide to reading a peptide COA walks through each field in order.
What does reconstitution mean?
Reconstitution is the step where a freeze dried peptide powder is returned to solution by adding a measured volume of solvent, typically bacteriostatic water in laboratory settings. The resulting concentration depends on the mass in the vial and the volume added. Our reconstitution guide describes the handling routine.
What does lyophilised mean?
Lyophilised means freeze dried. The peptide is frozen and the solvent is removed under vacuum, leaving a dry cake or powder that is more stable in storage than a solution. Most research peptides are supplied lyophilised in a sealed vial.
What is the difference between purity and peptide content?
Purity, usually measured by HPLC, describes what proportion of the peptide material in the vial is the target sequence rather than related impurities. Peptide content, sometimes called net peptide, describes what proportion of the total vial mass is peptide rather than residual water, salts and counterions. A lot can show high purity and lower peptide content at the same time, because the two measure different things.
What is bacteriostatic water?
Bacteriostatic water is sterile water containing a small proportion of benzyl alcohol, which inhibits bacterial growth and allows a vial to be accessed more than once in laboratory work. Plain sterile water contains no such agent and is used for single access preparations.
What does in vitro mean on a product listing?
In vitro means in glass, that is, work carried out in a controlled laboratory environment such as cell culture or an assay plate, rather than in a living organism. Stating that material is for in vitro research only signals that it is not a medicine, not a supplement and not intended for human or veterinary use.
For research purposes only. Not for human consumption. This article is educational and references published laboratory research; it is not medical advice and does not describe an approved use of any compound.