Peptide glossary
The 30 terms that show up most often in protocols, lab reports and forum posts, each defined the way you would explain it to a friend.
- Peptide
- A short chain of amino acids that carries a signal in the body.
- Amino acid
- The building block that peptides are made of.
- Receptor
- The docking point on a cell that a peptide binds to.
- Agonist
- A compound that switches a receptor on.
- GLP-1
- A gut hormone that manages blood sugar and appetite.
- GIP
- A second gut hormone that works alongside GLP-1.
- Glucagon receptor
- The third target in triple-agonist compounds.
- Incretin
- The family name for gut hormones like GLP-1 and GIP.
- Secretagogue
- A compound that prompts the body to release its own hormone.
- Half-life
- How long it takes for half the dose to clear.
- Steady state
- The point where what goes in matches what clears out.
- Titration
- Stepping a dose up gradually.
- Reconstitution
- Adding liquid to a freeze-dried vial to make it usable.
- Lyophilized
- Freeze-dried into a stable powder.
- Bacteriostatic water
- Sterile water with benzyl alcohol added to limit bacterial growth.
- Concentration
- How much peptide sits in each millilitre of liquid.
- Unit (IU on a syringe)
- On a U-100 insulin syringe, one unit is 0.01 mL.
- Draw volume
- The amount of liquid you pull for one dose.
- Microgram (mcg)
- One thousandth of a milligram.
- Subcutaneous (subQ)
- Injected into the fat layer just under the skin.
- Intramuscular (IM)
- Injected into muscle tissue.
- Injection site rotation
- Moving where you inject so tissue can recover.
- Cycle
- A defined run of weeks on a peptide, followed by time off.
- Receptor desensitisation
- A receptor responding less to the same signal over time.
- Bioavailability
- How much of a dose actually reaches the bloodstream.
- Lean mass loss
- Losing muscle alongside fat during rapid weight loss.
- COA (certificate of analysis)
- A lab document reporting purity and identity for a batch.
- Third-party testing
- Testing done by a lab the seller does not own.
- Purity
- The share of the contents that is the stated peptide.
- Research use only
- The legal status most research peptides are sold under.