Peptide Research Glossary: Reconstitution, Purity, Receptor, and Storage Terminology

A reference glossary of common terminology you’ll encounter in peptide research literature, dosing guides, and certificates of analysis. Bookmark this page for quick lookups.

Reconstitution & dosing terms

Reconstitution

The process of dissolving a lyophilized (freeze-dried) peptide powder back into solution, typically by adding bacteriostatic water to the sealed vial. Reconstitution converts the dry research material into a measurable, injectable-volume liquid.

Bacteriostatic water (BAC water)

Sterile water containing 0.9% benzyl alcohol as a preservative. The benzyl alcohol inhibits bacterial growth, making BAC water the preferred diluent for reconstituting research peptides that will be used over multiple sessions.

Lyophilized

Freeze-dried under vacuum. The standard form for shipping research peptides because removing water dramatically extends shelf life. Lyophilized peptides need to be reconstituted before use.

Concentration

The amount of peptide per unit volume of solution, usually expressed in mg/mL or mcg/mL. Concentration determines how many milliliters or insulin units correspond to a target research dose.

Aliquot

A measured sub-portion of a reconstituted peptide solution, transferred into a separate vial. Aliquoting protects the bulk supply from repeated freeze-thaw cycles, which degrade peptide stability.

Titration

A research protocol that gradually escalates dose over time — often weekly — to allow study models to adjust before reaching target dose levels.

Purity & quality terms

HPLC (High-Performance Liquid Chromatography)

The standard analytical method for measuring peptide purity. HPLC separates components of a solution and quantifies them, expressed as a percentage. Research-grade peptides typically aim for ≥99% HPLC purity.

Mass spectrometry (MS)

A complementary analytical method that verifies the molecular weight of a peptide matches its expected structure. HPLC measures purity; MS confirms identity. Pairing the two is standard for high-quality research peptides.

Certificate of Analysis (COA)

A lab-issued document that reports HPLC purity, mass spectrometry results, and other quality parameters for a specific manufacturing batch. Reputable suppliers publish COAs per lot.

Endotoxin

A bacterial contaminant byproduct that can confound research outcomes. Research-grade peptides are typically tested for low endotoxin levels (often via LAL assay).

Receptor-class terms

GLP-1 receptor agonist

A compound that activates the glucagon-like peptide-1 receptor, mimicking the endogenous hormone GLP-1. Studied for effects on glucose-dependent insulin secretion, satiety pathways, and gastric emptying. Semaglutide is the prototypical example.

GIP receptor agonist

A compound that activates the glucose-dependent insulinotropic polypeptide receptor. Often combined with GLP-1 activity in dual agonists like Tirzepatide.

Glucagon receptor agonist

A compound that activates the glucagon receptor — studied for direct effects on energy expenditure, lipolysis, and hepatic metabolism. Retatrutide is a triple agonist that includes glucagon activity.

GHRH analog

A peptide that mimics growth-hormone-releasing hormone, stimulating pulsatile growth hormone release from the pituitary. Tesamorelin is a synthetic GHRH analog studied in research literature.

GH secretagogue

A compound that triggers growth hormone release through a different mechanism than GHRH — often binding the ghrelin receptor instead. Ipamorelin, MK-677 (Ibutamoren), and CJC-1295 are examples.

Peptide-class shorthand

Pentadecapeptide

A peptide consisting of 15 amino acids. BPC-157 is the most-studied pentadecapeptide in research literature.

Tripeptide

A peptide of 3 amino acids. KPV (Lys-Pro-Val) and GHK-Cu (when bound with copper) are examples.

Melanocortin receptor agonist

A compound that binds receptors in the melanocortin family. PT-141 (Bremelanotide) is the most-studied melanocortin agonist in research.

Mitochondrial-derived peptide

A peptide encoded by mitochondrial DNA, secreted from mitochondria as a signaling molecule. MOTS-C is the most-studied example.

Storage & stability terms

Freeze-thaw cycle

One round of freezing a peptide solution and thawing it back to liquid. Each cycle measurably degrades peptide stability. Single-use aliquots eliminate the problem.

Oxidation

Chemical degradation caused by exposure to oxygen and light. Methionine, tryptophan, and cysteine residues are particularly vulnerable. Light-protected, refrigerated storage slows oxidation significantly.

Hygroscopic

A material that readily absorbs moisture from the air. Most lyophilized peptides are hygroscopic — once a vial is opened, ambient humidity can compromise stability if storage isn’t tight.

Research-use terms

For research use only (RUO)

A regulatory designation indicating a product is sold for laboratory research, not for human or veterinary use, diagnosis, or treatment. All Prax Peptides products are research-use only.

Research-grade

Material that meets purity, identity, and quality standards suitable for laboratory research — typically third-party verified ≥99% HPLC purity with a COA per batch.

Want to go deeper?

• Peptide reconstitution calculator — translates these concepts into exact research-dose math
• Peptide storage guide — temperature, shelf life, and stability best practices
• Peptide purity testing guide — HPLC, mass spec, and COA verification explained
• Browse research peptides