Peptide Glossary — Research Terms A–Z

Amino Acid Science

The fundamental building blocks of peptides and proteins. There are 20 standard amino acids, each with a unique side chain (R group) that determines its chemical properties. Peptides are formed when amino acids are linked together by peptide bonds.

Analogue Compound

A structural derivative of a naturally occurring compound, modified to alter properties such as receptor binding affinity, metabolic stability or half-life. Many research peptides — including SM1 and TZ2 — are analogues of naturally occurring hormones.

Agonist Science

A compound that binds to a receptor and activates it to produce a biological response. GLP-1 receptor agonists (such as SM1 and RT3) bind to and activate the GLP-1 receptor.

See also: Receptor, GLP-1, Antagonist

Antagonist Science

A compound that binds to a receptor but blocks or dampens the receptor's response. Unlike an agonist, an antagonist does not activate the receptor. Used in research to study receptor function by blocking specific pathways.

Albumin Binding Science

A modification technique used in some synthetic peptides (including SM1) where a fatty acid chain is attached to the peptide, allowing it to bind to albumin (a blood plasma protein). Albumin binding significantly extends the half-life of research compounds by slowing their clearance.

Bacteriostatic Water Process

Sterile water containing 0.9% benzyl alcohol as a preservative. The standard reconstitution solvent for research peptides. The benzyl alcohol inhibits bacterial growth, extending the usable life of reconstituted solutions to approximately 28 days under refrigeration. Not the same as sterile water or water for injection.

Batch Number General

A unique identifier assigned to a specific production batch of a research compound. Batch numbers allow researchers to trace compounds back to their synthesis records and associated Certificates of Analysis (COAs). Important for research reproducibility and documentation.

Bioavailability Science

The proportion of a compound that reaches the systemic circulation when introduced to the body. Relevant in in vivo research models. Most research peptides have low oral bioavailability due to enzymatic degradation in the gastrointestinal tract, which is why they are typically studied via subcutaneous or intravenous routes in animal models.

BPC-157 Compound

Body Protection Compound 157. A synthetic pentadecapeptide (15 amino acids) derived from a protective gastric protein. Used in laboratory research to study tissue repair, angiogenesis and gastrointestinal function. Available from Pyrox Labs in combination blend format — see the full BPC-157 Research Guide.

Also known as: PL 14736

Cagrilintide Compound

A long-acting amylin analogue research compound. Amylin is a peptide co-secreted with insulin from pancreatic beta cells. Cagrilintide is studied for its amylin receptor agonist activity and is currently under research as part of combination protocols with GLP-1 receptor agonists.

Certificate of Analysis (COA) General

A document issued by the manufacturer or an independent testing laboratory confirming the identity, purity and quality of a research compound. A COA typically includes information on molecular weight, purity percentage (usually by HPLC), appearance and batch number. Available from Pyrox Labs on request — see our full COA Hub.

CJC-1295 Compound

A synthetic analogue of growth hormone releasing hormone (GHRH). CJC-1295 is modified with a drug affinity complex (DAC) to extend its half-life through albumin binding. Used in research studying growth hormone secretion pathways. Available from Pyrox Labs in combination with Ipamorelin.

Concentration Process

The amount of a compound dissolved in a given volume of solvent, typically expressed in micrograms per millilitre (mcg/ml) or milligrams per millilitre (mg/ml). Concentration is determined by the amount of peptide in the vial and the volume of bacteriostatic water added during reconstitution. Use the Pyrox Labs reconstitution calculator to determine your concentration.

Da (Dalton) Science

The standard unit of molecular mass used in biochemistry. One Dalton is approximately equal to the mass of a hydrogen atom. Peptide molecular weights are typically expressed in Daltons (Da) or kilodaltons (kDa). For example, SM1 has a molecular weight of approximately 4,113 Da.

DSIP Compound

Delta Sleep Inducing Peptide. A naturally occurring neuropeptide first identified in the 1970s. DSIP is studied in research contexts examining sleep regulation, stress responses and neuroendocrine function. A nonapeptide (9 amino acids) with a complex modulating role in the central nervous system.

Dual Agonist Science

A compound that simultaneously activates two different receptors. TZ2 is a dual GLP-1/GIP receptor agonist, activating both the GLP-1 receptor and the glucose-dependent insulinotropic polypeptide (GIP) receptor. Dual agonism allows researchers to study the combined effects of two receptor pathways.

See also: Triple Agonist, GLP-1, GIP

Endogenous Science

Originating from within an organism. Endogenous peptides are those produced naturally by the body, such as native GLP-1, insulin or ghrelin. Research compounds are typically synthetic (exogenous) versions or analogues of endogenous peptides.

Opposite of: Exogenous

Exogenous Science

Originating from outside an organism. Research peptides supplied by Pyrox Labs are exogenous compounds synthesised in a laboratory environment. All Pyrox Labs compounds are for research use only and are not intended for exogenous administration to humans.

Freeze Drying Process

See: Lyophilisation

Full Agonist Science

A compound that binds to a receptor and produces the maximum possible response that the receptor is capable of. Distinguished from partial agonists, which produce a submaximal response even at full receptor occupancy. Most GLP-1 receptor agonist research compounds are full agonists.

GHK-Cu Compound

Glycyl-L-histidyl-L-lysine copper complex. A naturally occurring tripeptide-copper complex found in human plasma. GHK-Cu is extensively studied in research examining tissue remodelling, wound healing signalling and anti-inflammatory pathways. Available from Pyrox Labs in 50mg research vials.

GIP (Glucose-Dependent Insulinotropic Polypeptide) Science

An incretin hormone secreted by K-cells in the upper small intestine in response to food intake. GIP receptors are expressed in pancreatic beta cells, adipose tissue, bone and the central nervous system. The GIP receptor is targeted alongside the GLP-1 receptor by TZ2 and RT3.

Also known as: Gastric inhibitory polypeptide

GLP-1 (Glucagon-Like Peptide-1) Science

An endogenous incretin hormone produced by L-cells in the intestinal epithelium in response to nutrient ingestion. GLP-1 is a 30 amino acid peptide derived from proglucagon. It plays a key role in glucose homeostasis. Synthetic GLP-1 receptor agonist research compounds include SM1, TZ2 and RT3 — see our full GLP-1 Research Guide.

Glucagon Receptor Science

A G protein-coupled receptor (GPCR) expressed primarily in the liver, kidneys and heart. Glucagon receptor activation stimulates hepatic glucose output and energy expenditure. The glucagon receptor is the third receptor targeted by RT3 in addition to GLP-1R and GIPR.

Half-Life Science

The time required for the concentration of a compound in a biological system to reduce by half. Half-life is a key consideration in research protocols as it determines dosing frequency and duration of effect in in vivo models. Native GLP-1 has a half-life of only 1–2 minutes; SM1 has been engineered to have a half-life of approximately 7 days through fatty acid modification and albumin binding.

HPLC (High-Performance Liquid Chromatography) Process

An analytical technique used to separate, identify and quantify components in a mixture — see this detailed HPLC overview for further reading. HPLC is the standard method for determining the purity of research peptides. A purity of ≥98% by HPLC is generally considered high quality for research-grade compounds. Purity data is included in COA documentation.

IGF-1 LR3 Compound

Insulin-Like Growth Factor 1 Long R3. A modified form of IGF-1 with an arginine substitution at position 3 and a 13 amino acid N-terminal extension. These modifications reduce binding to IGF binding proteins, extending its half-life in research models. Used in research studying growth factor signalling pathways.

Incretin Science

A class of metabolic hormones that stimulate a decrease in blood glucose levels in a glucose-dependent manner. The two main incretins are GLP-1 and GIP. Incretin hormones are secreted by intestinal cells in response to food intake and form the basis for GLP-1 receptor agonist research compounds.

In Vitro General

Latin for "in glass." Refers to research or experiments conducted outside of a living organism, typically in a controlled laboratory environment such as cell cultures or test tubes. All Pyrox Labs compounds are supplied for in vitro research use only.

Opposite of: In Vivo

In Vivo General

Latin for "within the living." Refers to research conducted within a living organism. In vivo research typically takes place in validated animal model studies under appropriate institutional and regulatory oversight. Pyrox Labs compounds are not approved for human in vivo use.

Ipamorelin Compound

A synthetic pentapeptide growth hormone secretagogue and ghrelin receptor agonist. Ipamorelin selectively stimulates growth hormone release in research models with minimal effect on other pituitary hormones. Available from Pyrox Labs in combination with CJC-1295.

Lyophilisation Process

Also known as freeze-drying. A dehydration process used to preserve research compounds by removing water content through sublimation under low temperature and pressure. Lyophilised peptides are more stable during storage and transportation than liquid solutions. All Pyrox Labs compounds are supplied in lyophilised (powder) form.

Also known as: Freeze-drying

Lyophilised Powder Process

The freeze-dried form of a research compound. Lyophilised peptides appear as a white or off-white powder or cake in the vial. They must be reconstituted with bacteriostatic water before use in research applications. See the Pyrox Labs Reconstitution Guide for full instructions.

mcg (Microgram) General

A unit of mass equal to one millionth of a gram (0.000001g) or one thousandth of a milligram. Commonly used when measuring research peptide concentrations. 1mg = 1,000 mcg. Research peptide vials are typically expressed in milligrams (mg) while working concentrations are often expressed in micrograms per millilitre (mcg/ml).

Molecular Weight (MW) Science

The sum of the atomic masses of all atoms in a molecule, expressed in Daltons (Da). Molecular weight is a key identifier for research compounds and is included on COA documentation. For example, RT3 has a molecular weight of approximately 4,683 Da.

MOTS-C Compound

Mitochondrial Open Reading Frame of the 12S rRNA-c. A mitochondria-derived peptide (MDP) encoded within the mitochondrial genome. MOTS-C is studied in research examining mitochondrial function, metabolic regulation, cellular stress responses and ageing pathways. Available from Pyrox Labs in 40mg research vials.

NAD+ (Nicotinamide Adenine Dinucleotide) Compound

A coenzyme found in all living cells, essential for energy metabolism and cellular repair processes. NAD+ plays a central role in mitochondrial function, DNA repair and sirtuin activation. Research interest in NAD+ has grown significantly in the context of ageing biology, metabolic function and cellular senescence research. Available from Pyrox Labs in 500mg research vials — see the full NAD+ Research Guide.

Nonapeptide Science

A peptide consisting of exactly nine amino acid residues. DSIP (Delta Sleep Inducing Peptide) is an example of a nonapeptide. The prefix "nona" derives from the Latin for nine.

Peptide Science

A short chain of amino acids linked by peptide bonds. Peptides typically contain between 2 and 50 amino acids; longer chains are generally classified as proteins. Peptides can be naturally occurring (endogenous) or synthetically manufactured. They play critical roles in biological signalling, enzyme function and structural processes throughout living organisms.

Peptide Bond Science

A covalent chemical bond formed between two amino acids when the carboxyl group of one amino acid reacts with the amino group of another, releasing a water molecule. Peptide bonds form the backbone structure of all peptides and proteins.

Polypeptide Science

A peptide chain containing a relatively large number of amino acids, typically more than 10. The distinction between a polypeptide and a protein is not always clear-cut but proteins are generally defined as functional polypeptides that have folded into a specific three-dimensional structure.

Purity General

The proportion of the desired compound present in a research product, typically expressed as a percentage. Purity is measured by HPLC and reported on the COA. Research-grade peptides are generally expected to have a purity of ≥98%. Higher purity compounds produce more reliable and reproducible research results.

Receptor Science

A protein molecule, usually located on the surface of or within a cell, that receives and responds to chemical signals (ligands). When a compound binds to its receptor, it triggers a cascade of intracellular events. GLP-1 receptor agonists bind specifically to the GLP-1 receptor, a G protein-coupled receptor (GPCR).

Reconstitution Process

The process of dissolving a lyophilised (freeze-dried) research compound in a sterile liquid — typically bacteriostatic water — to create a solution for laboratory use. Reconstitution must be performed carefully to avoid damaging the compound. See the Pyrox Labs Reconstitution Guide for full step-by-step instructions.

See also: Lyophilisation, Bacteriostatic Water

RT3 Compound

A synthetic triple agonist research compound targeting GLP-1, GIP and glucagon receptors simultaneously. Also known as LY3437943. RT3 represents the current frontier of multi-receptor agonist research, enabling scientists to study the combined effects of three distinct metabolic signalling pathways in a single protocol. Available from Pyrox Labs in 10mg and 20mg research vials and multi-vial research bundles — see the full RT3 Research Guide.

Also known as: LY3437943 · Triple G Agonist

Selank Compound

A synthetic heptapeptide analogue of the endogenous tetrapeptide tuftsin. Selank is studied in neuroscience research for its interactions with GABAergic and serotonergic systems, as well as its effects on anxiety-related pathways in animal models. Developed at the Institute of Molecular Genetics in Russia.

SM1 Compound

A synthetic GLP-1 receptor agonist analogue sharing approximately 94% sequence homology with native human GLP-1. SM1 incorporates a C18 fatty diacid modification via a hydrophilic linker, enabling strong albumin binding and extending half-life significantly compared to native GLP-1. One of the most widely studied GLP-1 receptor agonist compounds in biochemical research. Available from Pyrox Labs in 5mg and 10mg research vials — see the full SM1 Research Guide.

Molecular Formula: C₁₈₄H₂₉₁N₄₅O₅₉ · MW: 4,113.6 Da

Semax Compound

A synthetic heptapeptide derived from the N-terminal fragment of adrenocorticotropic hormone (ACTH). Semax is used in neuroscience research examining BDNF (Brain-Derived Neurotrophic Factor) pathways, cognitive function models and neuroprotection research. Developed in Russia in the 1980s.

SS-31 Compound

Also known as Elamipretide or MTP-131. A mitochondria-targeted tetrapeptide that selectively accumulates in the inner mitochondrial membrane. SS-31 is studied in research examining mitochondrial function, oxidative stress and cardioprotection pathways. Available from Pyrox Labs in 50mg research vials.

Also known as: Elamipretide · MTP-131

Subcutaneous Science

Referring to the tissue layer beneath the skin. In in vivo research models, subcutaneous administration involves injecting a compound into this tissue layer. Subcutaneous is a common administration route in peptide research animal models due to the relatively slow absorption rate, which can mirror physiological release patterns.

Synthesis (Peptide Synthesis) Process

The chemical process of creating peptides by joining amino acids together in a specific sequence. The most common laboratory method is Solid Phase Peptide Synthesis (SPPS), where amino acids are added sequentially to a resin-bound chain. The purity and quality of the synthesis process is a critical determinant of research compound quality.

TB-500 Compound

A synthetic version of Thymosin Beta-4 (Tβ4), a naturally occurring 43 amino acid peptide present in virtually all human and animal cells. TB-500 is studied in research examining actin regulation, tissue repair signalling, angiogenesis and inflammatory pathway modulation. Available from Pyrox Labs in combination with BPC-157.

Also known as: Thymosin Beta-4 · Tβ4

Tesamorelin Compound

A synthetic analogue of growth hormone releasing hormone (GHRH) consisting of the full 44 amino acid sequence of GHRH with a trans-3-hexenoic acid group modification. Used in research examining growth hormone secretagogue pathways, visceral adipose tissue regulation and metabolic function.

TZ2 Compound

A synthetic dual GLP-1/GIP receptor agonist research compound. Also known as LY3298176. TZ2's simultaneous activation of both GLP-1 and GIP receptors allows researchers to study the additive effects of dual incretin pathway stimulation compared to GLP-1 mono-agonism. GIP receptor expression in adipose tissue, bone and CNS opens additional research dimensions not available with SM1. Available from Pyrox Labs in 5mg, 10mg and 20mg research vials — see the full TZ2 Research Guide.

Also known as: LY3298176 · Dual GIP/GLP-1 RA

Triple Agonist Science

A compound that simultaneously activates three different receptors. RT3 is a triple GLP-1/GIP/Glucagon receptor agonist. Triple agonism represents the current frontier of metabolic peptide research, enabling scientists to study the combined and potentially synergistic effects of three distinct signalling pathways.

See also: Dual Agonist, RT3

Vial General

A small sealed glass container used to store research compounds. Research peptides are typically supplied in borosilicate glass vials sealed with a rubber stopper and aluminium crimp cap. The rubber stopper allows needles to be inserted for drawing and adding solutions while maintaining sterility.

Water For Injection (WFI) Process

Highly purified sterile water that meets specific pharmaceutical standards. Different from bacteriostatic water in that it contains no preservatives. WFI is suitable for single-use reconstitution applications but does not extend the shelf life of reconstituted solutions. For multi-use vials, bacteriostatic water is recommended.