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74 Terms · Updated Reference
Peptide Glossary:
A–Z Reference
Researchers are familiar with lab results and peptide calculator readings, but sometimes they get confused about specific terms related to peptides. Here we explain, in the glossary, each and every term that you may come to read or hear during research in labs, universities, or research academies. Simple, plain-English meanings for every term you'll see in research peptide science — from basic amino acid facts to the exact compounds we stock, each one linked straight through to the research material itself.
74+
Terms Defined
26
Letters Covered
20+
Linked Products
UK
Research Supply
✦ In-Vitro Research Use Only
✦ A–Z Reference
✦ Linked To 20+ Research Peptides
✦ Updated As New Products Land
✦ UK Lab-Tested Supply
✦ In-Vitro Research Use Only
✦ A–Z Reference
✦ Linked To 20+ Research Peptides
✦ Updated As New Products Land
✦ UK Lab-Tested Supply
A
5 terms
Agonist
A molecule that attaches to a receptor and switches it on, causing a biological effect. Peptides PT-141 are labeled as receptor agonists.
Amino Acid
Amino acid is a basic building block of peptides and proteins. It is made of an amino group, a carboxyl group, and a side chain that changes from one amino acid to another.
AOD-9604
AOD-9604 is a modified piece of human growth hormone (parts 176–191), studied for its role in metabolism and fat research. See our AOD-9604.
Antagonist
Antagonist is a functional opposite of agonist. It is a compound that attaches to a receptor but blocks or weakens its activity.
Assay
Assay is a lab test or procedure used to measure the presence, concentration, or biological activity of a substance such as a peptide.
B
5 terms
Bacteriostatic Water
Bacteriostatic Water (BAC) is a sterile liquid containing a small amount of benzyl alcohol, used to mix freeze-dried peptides back into liquid form. Shop 3ml or 10ml.
Bioactive Peptide
Bioactive peptide is a peptide sequence that has a measurable effect on living tissue or cell cultures.
Bioavailability
Bioavailability is actually the portion of a compound that enters the bloodstream and becomes able to act biologically.
BPC-157
BPC-157 is a man-made peptide made of 15 amino acids, studied for tissue-repair research. Browse 10mg and 5mg BPC-157.
Buffer
Buffer is a solution that keeps pH levels stable. It is used to help mix (reconstitute) and store peptides safely.
C
4 terms
Certificate of Analysis (COA)
COA is a lab document that confirms a peptide batch's purity, identity, and quality, usually produced using HPLC and mass spectrometry.
CJC-1295
CJC-1295 is a man-made version of growth hormone-releasing hormone (GHRH). See CJC-1295 (no DAC) or the CJC-1295 + Ipamorelin blend.
Cold Chain
Cold Chain: An uninterrupted, temperature-controlled process used to keep peptides stable from the time they're prepared through to storage.
Cytokine
Cytokine is a small signaling protein released by cells, used in cell-to-cell communication and immune research.
Chromatography
Chromatography is a lab technique used to separate the different parts of a mixture, often used to check a peptide's purity.
D
4 terms
DAC (Drug Affinity Complex)
DAC is a chemical modification that extends a peptide's active life by allowing it to bind directly to albumin in the bloodstream.
Denaturation
Denaturation is when a peptide's structure comes undone, usually caused by heat, extreme pH, or shaking, making it lose its biological activity.
Diluent
Diluent is a liquid (e.g. BAC) used to turn a freeze-dried peptide back into a solution. See acetic acid water.
Dipeptide
Dipeptide is a term used for a peptide made of exactly two amino acids joined by a single peptide bond.
E
3 terms
Elamipretide (SS-31)
A man-made (synthetic) peptide made of four amino acids that targets mitochondria, studied in cell-energy research. See SS-31 10mg or SS-31 50mg.
Enzyme
Enzyme is a protein that speeds up chemical reactions, often building or breaking down peptides in biological systems.
Excipient
Excipient is an inactive ingredient added to a peptide (for example mannitol) to help keep it stable during freeze-drying.
F
3 terms
FOXO4-DRI
A peptide made to interfere with the interaction between the FOXO4 and p53 proteins, studied in research on cell ageing. See FOXO4-DRI.
Fragment
Term fragment used for a shorter piece of a larger peptide, such as HGH Fragment 176-191, that keeps a specific part of biological interest.
Freeze-Drying (Lyophilisation)
Freeze-Drying is a process that removes water from a frozen peptide solution using a vacuum, producing a stable powder for storage.
G
4 terms
GHK-Cu
A naturally occurring tripeptide that binds copper, studied for tissue and skin research. Shop GHK-Cu, and read about its studied effects.
GHRH
GHRH is an endogenous hormone that stimulates growth hormone release; serves as the basis for synthetic analogs like Tesamorelin and CJC-1295.
GHRP
A group of synthetic (man-made) peptides studied for how they interact with growth hormone secretagogue receptors to stimulate growth hormone release.
GLOW Blend
A mix of BPC-157, GHK-Cu and TB-500, studied together in tissue-repair and skin research. See our GLOW Blend.
Growth Hormone Secretagogue Receptor (GHS-R)
A receptor that, when activated, triggers the release of growth hormone. GHRP-type peptides are studied for how they act on this receptor.
H
3 terms
HGH Fragment 176-191
A truncated segment of human growth hormone, studied in metabolism and fat-loss research. See HGH Fragment.
HPLC
High-Performance Liquid Chromatography, the standard method for checking a peptide's purity and identity.
Hydrophilic / Hydrophobic
Hydrophilic/ Hydrophobic are terms describing whether a molecule attracts water/is water-soluble (hydrophilic) or repels water/is water-insoluble (hydrophobic), which dictates how it dissolves and is formulated.
Half-Life
The time required for half of a substance to break down or clear from a system, used to measure how long a peptide remains active in biological research.
I
3 terms
IGF-1 LR3
IGF-1 LR3 is a longer-lasting version of insulin-like growth factor 1, changed so it resists breaking down. See IGF-1 LR3.
In-Vitro
In-vitro means when research is done outside a living organism, for example, in a test tube or cell culture. All products here are for in-vitro research only; see our note for UK researchers.
Ipamorelin
A specific GHRP studied for triggering growth hormone release with little effect on other hormones. See the CJC-1295 + Ipamorelin blend.
Isoelectric Point
Isoelectric point is the pH level at which a peptide carries no overall electrical charge, relevant to how it dissolves and behaves in solution.
J
1 term
JAK-STAT Pathway
A cell-signalling pathway often mentioned in research on cytokines and peptide receptors, linking receptor activity to gene activity.
K
2 terms
Kilodalton (kDa)
Kilodalton (kDa) is a unit equal to 1,000 daltons, used to measure the size of peptides and proteins.
KPV
A short three-amino-acid piece of alpha-MSH, studied for its possible anti-inflammatory properties.
L
3 terms
Ligand
Any molecule that attaches to a specific spot on a receptor or protein, causing or blocking a biological response.
LR3
Short for "Long Arg3", the change used in IGF-1 LR3 that helps it stay stable in solution.
Lyophilisation
Lyophilisation (or lyophilization) is the formal technical term for freeze-drying, a dehydration process typically used to preserve biological material or peptides for storage.
M
3 terms
Melanocortin
Melanocortin is a part of a group of peptide hormones, including some studied for libido and skin-colour research, such as PT-141.
Mitochondrial Peptide
Accurately identifies peptides like SS-31 that target cellular energy and mitochondrial function.
Molecular Weight
Molecular Weight is the mass of a peptide molecule, usually given in daltons or kilodaltons, which affects how it dissolves and behaves.
Mass Spectrometry
Mass Spectrometry is a lab technique that measures the mass of molecules, used to confirm a peptide's identity alongside HPLC.
Molarity
A way of measuring how concentrated a solution is, based on the amount of a substance dissolved in a set volume of liquid.
N
3 terms
NAD+ (Nicotinamide Adenine Dinucleotide)
A critical coenzyme found in all living cells involved in redox reactions and cellular energy production, widely studied in longevity and metabolic research. Shop 500mg or 1000mg.
Neuropeptide
A small, protein-like messenger molecule (short amino acid chain) produced and released by neurons to communicate and modulate signals in the nervous system.
Nomenclature
The systematic naming conventions used for peptides, typically based on their amino acid sequence, physiological origin, or structural modifications (e.g., "LR3", "DAC", "BPC-157").
O
2 terms
Oligopeptide
A peptide chain made of a small number of amino acids, usually between two and twenty.
Osmolarity
The total concentration of solute particles in a solution, which is essential to match when preparing peptide solutions to prevent cellular stress or tissue damage.
P
4 terms
Peptide Bond
Peptide bond accurately describes the condensation reaction (releasing water) that links amino acids together via carboxyl and amino groups.
Peptidomimetic
A man-made compound designed to copy a natural peptide's activity while being more stable or better absorbed.
PT-141 (Bremelanotide)
A man-made peptide similar to alpha-MSH, studied for how it interacts with melanocortin receptors. See PT-141.
Purity
The percentage of a sample made up of the intended compound, usually checked by HPLC (e.g. "≥98% purity").
pH
A scale used to measure how acidic or alkaline a solution is, which affects a peptide's stability and structure.
Q
2 terms
Quality Control (QC)
The testing steps, including HPLC and mass spectrometry, used to confirm a batch matches its stated purity and identity before it's sold.
Quaternary Structure
Correctly defines the assembly of multiple distinct polypeptide subunits into a multi-subunit protein complex, contrasting it with smaller, single-chain peptides.
R
3 terms
Receptor
A protein, usually on the outside of a cell on its surface, that attaches to specific molecules (ligands) and causes a biological response.
Reconstitution
Adding a liquid, such as bacteriostatic water, to a freeze-dried peptide to turn it back into a solution. Read our reconstitution guide or BPC-157 mixing guide.
Research Use Only (RUO)
A label showing that a product is meant only for lab research, not for use in humans or animals. See our FAQ.
S
5 terms
Somatostatin
Somatostatin is a peptide hormone that slows the release of growth hormone and insulin, helping regulate the endocrine system.
SS-31
See Elamipretide, above.
Sterile
Correctly defines the complete absence of viable microorganisms, which is critical for preventing contamination in injectable solutions.
Storage & Stability
Accurately outlines the temperature, light, and moisture parameters needed to prevent peptide degradation (e.g., hydrolysis, oxidation). See our peptide storage box.
Synthetic Peptide
A peptide made artificially, usually through solid-phase peptide synthesis, rather than taken from a natural source.
Secretagogue
A substance that causes another substance, such as a hormone, to be released. GHRPs are studied as growth hormone secretagogues.
Shelf Life
The length of time a peptide stays stable and usable when stored correctly, before it starts to break down.
Solid-Phase Peptide Synthesis (SPPS)
The most common lab method for building peptides, where amino acids are added one at a time to a chain attached to a solid support.
Subcutaneous
Referring to the layer of tissue just under the skin, a term often used in research when describing injection sites.
T
3 terms
TB-500
A man-made piece of Thymosin Beta-4, widely studied in tissue-repair and recovery research. See TB-500 and our TB-500 research guide.
Tesamorelin
Tesamorelin is a man-made version of GHRH, studied for growth hormone research. See 10mg and 20mg.
Tripeptide
Tripeptide is a peptide made of exactly three amino acids joined by two peptide bonds, such as GHK-Cu.
Titration
The process of adjusting an amount step by step to reach a target concentration or effect, often referenced in dose-response research.GHK-Cu.
U
2 terms
Uptake
Uptake is the process by which a cell takes in a peptide or other molecule through its outer membrane.
USP Grade
A purity standard (United States Pharmacopeia) sometimes used for water and other ingredients in peptide preparation.
V
2 terms
Vasopressin
A peptide hormone involved in water balance and blood pressure control, often mentioned in comparisons of peptide hormones.
Vial
The sealed, sterile container used to store peptides. Shop vials, stoppers & flip caps or sterile 10ml vials.
Vial Adapter
A small fitting attached to a vial that pierces the stopper once, allowing syringes to connect without using needles each time.
W
2 terms
Water for Injection
See Bacteriostatic Water, above.
Wolverine Stack
A well-known (Popular) research combination of BPC-157 and TB-500. Read the Wolverine Stack guide or shop the 5mg blend.
X
1 term
X-Ray Crystallography
A technique used to work out the 3D atomic shape of a peptide by studying its crystal form.
Y
1 term
Yield
The amount of purified peptide obtained at the end of a synthesis, shown as a percentage of the highest possible amount.
Z
1 term
Zwitterion
A zwitterion is a molecule carrying both a positive and a negative charge at normal body pH — common in free amino acids and some peptides.
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Every peptide named in this glossary is in stock, lab-tested, and shipped from the UK.
All products referenced on this page are sold for in-vitro laboratory research use only. They are not medicines and are not intended for human or veterinary use, or for any therapeutic, diagnostic or clinical application. Definitions are provided for general educational reference only.