Peptide Glossary
Clear, research-grade definitions for the terminology used across peptide science, administration, and protocols. Every term is written for both newcomers and experienced researchers.
Peptide Basics
Peptide
A peptide is a short chain of amino acids linked by peptide bonds, typically containing 2 to 50 amino acids. Peptides are smaller than proteins and serve as signaling molecules, hormones, and neurotransmitters in the body.
Amino Acid
Amino acids are the building blocks of peptides and proteins. There are 20 standard amino acids that combine in different sequences to create the thousands of different peptides found in biology.
Administration & Preparation
Reconstitution
Reconstitution is the process of dissolving a lyophilized (freeze-dried) peptide powder into a sterile solution for research use. Bacteriostatic water is the most common reconstitution solvent.
Subcutaneous Injection
A subcutaneous injection delivers a substance into the fatty tissue layer between the skin and muscle. This is the most common administration route for research peptides.
Bacteriostatic Water
Bacteriostatic water is sterile water containing 0.9% benzyl alcohol as a preservative. It prevents bacterial growth in reconstituted peptide solutions, extending their usable lifespan.
Intramuscular Injection
An intramuscular (IM) injection delivers a substance directly into muscle tissue. Some peptides use IM injection for faster absorption compared to subcutaneous routes.
Intranasal Administration
Intranasal administration delivers peptides through the nasal mucosa, providing a non-invasive route with potential for direct brain delivery via the olfactory pathway.
Insulin Syringe
Insulin syringes are small-volume syringes (typically 0.3-1 mL) with fine gauge needles (29-31G) designed for precise measurement of small doses. They are the standard tool for peptide injection.
Concentration (mg/mL)
Concentration describes the amount of peptide dissolved per unit volume of solution, expressed in milligrams per milliliter (mg/mL). It is determined by how much solvent is added during reconstitution.
Science & Mechanisms
Lyophilization (Freeze-Drying)
Lyophilization is a preservation process that removes water from a peptide solution by freezing it and then reducing pressure to sublimate the ice directly into vapor. This creates a stable powder form.
Half-Life
A peptide's half-life is the time it takes for half of the administered dose to be cleared from the bloodstream. Half-life determines how frequently a peptide needs to be administered.
Bioavailability
Bioavailability is the proportion of an administered peptide that reaches systemic circulation in its active form. Subcutaneous injection typically provides 65-95% bioavailability for peptides.
Peptide Bond
A peptide bond is the chemical bond formed between the carboxyl group of one amino acid and the amino group of another through a dehydration reaction. This bond is the backbone of all peptides.
Melanocortin Receptor
Melanocortin receptors (MC1R through MC5R) are a family of G-protein coupled receptors that mediate pigmentation, appetite, sexual function, and inflammation. Key targets for peptides like Melanotan and PT-141.
Bioregulator Peptide
Bioregulator peptides are short peptide sequences (2-4 amino acids) that target specific organs and tissues to normalize cellular function. Developed from Russian research by Professor Vladimir Khavinson.
Protocols & Dosing
Growth Hormone Secretagogue (GHS)
A growth hormone secretagogue is a compound that stimulates the pituitary gland to produce and release growth hormone. GHS peptides include GHRP-2, GHRP-6, Ipamorelin, and Hexarelin.
Loading Phase
A loading phase is an initial period of higher or more frequent peptide dosing designed to establish therapeutic tissue concentrations before transitioning to lower maintenance doses.