Glossary of Scientific Terms

Working with research reagents requires precise language. The same compound may be described by a trade name, a laboratory code, a mechanistic class and a molecular formula — and the difference between an “agonist” and an “antagonist”, or between a “lyophilisate” and a “solution after reconstitution”, determines the correctness of an experiment. The glossary below collects definitions of the concepts that appear most often in the One-Peptides catalogue and knowledge base: analytical, regulatory, mechanistic and pharmacological terms.

Each entry is a concise, self-contained definition. Where a concept is expanded in a separate article, the name of the compound or mechanism leads to the full treatment in the knowledge base.

All substances mentioned in the glossary are discussed solely in a scientific context. The peptides and SARMs in the One-Peptides catalogue are chemical reagents intended for laboratory research (Research Use Only) — not medicines or dietary supplements. The definitions describe mechanisms and concepts, not use in humans.

A

Agonist

A molecule that binds to a cellular receptor and triggers its activation — a biological response analogous to that of the natural ligand. It is the opposite of an antagonist, which blocks the receptor. Most research peptides of the secretagogue group are agonists of the ghrelin or GHRH receptors. The potency of an agonist is described by two parameters: affinity for the receptor and intrinsic activity (the ability to elicit a full response).

Amylin analogue

A molecule that mimics the action of amylin — a hormone secreted together with insulin by the pancreatic β cells, regulating satiety and the rate of gastric emptying. A research example is cagrilintide, studied among other things in combination with GLP-1 agonists. Amylin acts through amylin receptors in the brainstem. Research on the analogues concerns mainly metabolism and body weight control.

Androgen receptor modulator

A molecule that interacts with the androgen receptor and modifies its activity. The concept covers full agonists, partial agonists and antagonists. Selective modulators (SARMs) are designed to act in a tissue-selective manner. This category is distinguished from compounds acting through other receptors — Cardarine (PPARδ) is sometimes mistakenly classed as an androgen receptor modulator, although it is not one.

Angiogenesis

The process of forming new blood vessels from existing ones. It is of central importance in wound healing, the regeneration of ischaemic tissues and embryonic development. Some regenerative peptides — Thymosin Beta-4, BPC-157 — show an effect on angiogenesis in animal models through modulation of vascular endothelial growth factors (VEGF). Heightened angiogenesis is also a feature of tumour tissues, which calls for interpretative caution.

Antagonist

A molecule that binds to a receptor without activating it — blocking the access of the natural ligand and inhibiting the biological response. A classic example is yohimbine, an antagonist of the alpha-2 adrenergic receptors. An antagonist may be competitive (reversible, competing with the ligand for the binding site) or non-competitive (binding a different site). It is the opposite of an agonist.

B

Bacteriostatic water

Sterile water with the addition of a bacteriostatic agent (usually 0.9% benzyl alcohol) that inhibits bacterial growth. In laboratory practice it serves as a solvent for reconstituting lyophilised peptides — the bacteriostatic agent allows the solution to be stored longer than sterile water without additives. It is a standard element of the kit for working with peptide reagents.

Batch traceability

The ability to assign each vial of a reagent to a specific production batch and the associated quality documentation. It makes it possible to reconstruct the analytical history of the material — the synthesis date, HPLC results, declared purity. This is the standard in the professional trade in research reagents and a condition for the reliability of an experiment: without linking the batch to a certificate of analysis, the result cannot be related to the confirmed quality of the material.

Bioavailability

The proportion of an administered substance that reaches the systemic circulation in unchanged form and remains biologically available. Orally administered peptides usually have low bioavailability, because they undergo proteolytic degradation in the gastrointestinal tract — for this reason parenteral routes are more often used in research. The exception is molecules designed for oral stability, such as orforglipron.

C

COA (Certificate of Analysis)

A document (a Certificate of Analysis) confirming the identity and purity of a specific batch of a reagent. It contains analytical results: HPLC purity, confirmation of the molecular weight by mass spectrometry, water content, endotoxin level. A COA linked to a batch number is the basic proof of the quality of research material. Without a certificate of analysis, the origin and composition of a reagent remain unverified.

Cold chain

An uninterrupted system of temperature control during the storage and transport of sensitive reagents. Peptides in lyophilisate form retain stability longest when frozen (-20°C), and solutions after reconstitution under refrigerated conditions (2–8°C). Breaking the cold chain can lead to degradation of the molecule and loss of biological activity, which distorts the results of research conducted on such material.

E

ERR agonist

A compound that activates the ERR receptors (estrogen-related receptors α/β/γ) — transcription factors regulating mitochondrial biogenesis and the energy metabolism of muscle. In preclinical research, ERR agonists such as SLU-PP-332 are studied as “exercise mimetics” affecting oxidative capacity without training. The data come mainly from animal models; the significance for human physiology remains under investigation.

G

Ghrelin mimetic

A compound that mimics the action of ghrelin — a hormone that stimulates growth hormone secretion and appetite through the GHS-R receptor. Ghrelin mimetics include peptide secretagogues (GHRP-2, GHRP-6, Ipamorelin) and oral molecules (MK-677). In research they are studied for their effect on the growth hormone axis. They are also referred to as GH secretagogues.

GLP-1 agonist

A molecule that activates the glucagon-like peptide 1 (GLP-1) receptor — an incretin that regulates glucose-dependent insulin secretion, gastric emptying and the feeling of satiety. The class includes semaglutide, liraglutide and the oral orforglipron. In clinical studies, GLP-1 agonists affect glycaemia and body weight. The GLP-1 receptor belongs to the family of G-protein-coupled receptors.

H

Half-life

The time after which the concentration of a substance in the blood falls by half. A pharmacokinetic parameter describing how long a compound remains active in the body. Modifications of the molecule — adding the DAC complex to CJC-1295 or pegylation of MGF — extend the half-life. This value matters when designing experimental schedules in studies conducted on animal models.

Heptapeptide

A peptide built from seven amino acid residues. An example is the LKKTETQ fragment — the active site of Thymosin Beta-4 responsible for actin binding, also referred to as TB-500 in the narrow, strict sense. Short peptides (oligopeptides) are sometimes studied as simplified, more stable counterparts of larger parent proteins, retaining part of their biological activity.

HPG axis (hypothalamic–pituitary–gonadal)

A hierarchical hormonal system regulating reproductive functions. The hypothalamus secretes GnRH, stimulating the pituitary to release LH and FSH, which in turn stimulate the gonads to produce sex hormones — testosterone and oestrogen. Kisspeptin acts as a higher-order regulator of this axis. The abbreviation comes from the hypothalamic–pituitary–gonadal axis.

HPLC (high-performance liquid chromatography)

An analytical technique (High-Performance Liquid Chromatography) that separates the components of a mixture on the basis of their affinity for the stationary phase of the column. In peptide quality control it is used to determine purity — it detects and quantifies impurities. The HPLC result, for example ≥98%, is the basic parameter of every certificate of analysis. The RP-HPLC variant (reversed phase) is the standard for peptides.

I

Incretin

A gut hormone secreted in response to a meal, enhancing glucose-dependent insulin secretion. The main incretins are GLP-1 and GIP. They are a point of action for metabolic compounds — GLP-1 agonists and dual GLP-1/GIP agonists such as tirzepatide. The incretin effect accounts for a substantial part of postprandial insulin secretion in a healthy person.

L

Lyophilisate

A substance in the form of a dry powder obtained by lyophilisation — freeze-drying, that is the removal of water from frozen material under reduced pressure. Most research peptides are supplied as a lyophilisate, because in this form they retain stability longest. Before use in an experiment, the lyophilisate requires reconstitution in an appropriate solvent, most often bacteriostatic water.

M

Mass spectrometry (MS)

An analytical technique that determines the molecular weight of a compound by measuring the mass-to-charge ratio of ionised molecules. In peptide quality control it confirms identity — the measured mass must match the theoretical mass of the sequence. Together with HPLC, which determines purity, it forms the basic set confirming that the material is the declared molecule. The ESI-MS variant is the standard for peptides.

MC4R receptor

The type 4 melanocortin receptor — a protein of the central nervous system involved in the regulation of appetite, energy expenditure and sexual function. It is a point of action for melanocortin peptides, including PT-141 (bremelanotide), studied in the context of libido. It belongs to the G-protein-coupled receptors. Mutations of the MC4R gene are associated with disorders of body weight regulation.

Mitochondrial uncoupler

A compound that uncouples oxidative phosphorylation — separating the oxidation of nutrients from ATP production, so that energy is dissipated as heat and the metabolic rate rises. A research example is BAM15. The mechanism is studied in models of metabolism and obesity. Classic uncouplers (e.g. DNP) have a narrow safety margin, which is why the topic is treated solely as a research matter.

Molecular formula

A notation specifying the number of atoms of each element in a molecule, for example C62H98N16O22 for Thymosin Beta-4 (TB-500). Together with the molecular weight and the amino acid sequence, it constitutes an unambiguous identification of a compound. It is sometimes searched for directly (e.g. “c62h98n16o22”) as a way of confirming the identity of a substance independently of the trade name or catalogue code.

N

NNMT inhibitor

A compound that inhibits the enzyme nicotinamide N-methyltransferase (NNMT), which is involved in energy metabolism and the regulation of the NAD+ pool. In preclinical research, NNMT inhibition — studied among others for 5-amino-1MQ — is considered in the context of adipose- and muscle-tissue metabolism. The data come from cell and animal models; the role in humans remains under investigation.

P

Pentadecapeptide

A peptide composed of fifteen amino acid residues. The best-known representative in the research context is BPC-157 — a pentadecapeptide derived from a fragment of a protein present in gastric juice, studied in tissue regeneration models. The number of amino acids (15) is one of the parameters identifying the molecule, alongside the full sequence and the molecular weight.

Peptide

A molecule built from amino acids joined by peptide bonds — a chain shorter than a protein, conventionally up to around 50 amino acids. Peptides perform signalling functions: they are hormones, growth factors and neurotransmitters. In the research trade they appear as synthetic counterparts of natural molecules. They are identified by their amino acid sequence and by the molecular weight confirmed by mass spectrometry.

PPARδ agonist

A compound that activates the nuclear receptor PPARδ (peroxisome proliferator-activated receptor delta), which regulates the expression of genes for fatty-acid metabolism and mitochondrial biogenesis. The best-known representative is GW-501516 (Cardarine). In animal models, activation of PPARδ shifts muscle metabolism towards lipid oxidation. Contrary to a common classification, it is not a SARM — it acts through an entirely different receptor.

Purity ≥98%

A parameter specifying the share of the target molecule in the material, determined by HPLC. A value of ≥98% means that impurities — incomplete sequences, synthesis by-products — account for less than 2% of the mass. In scientific research, purity has a direct effect on the reproducibility of results: impurities may distort the biological response and lead to misinterpretation of experimental data.

R

Reconstitution

The process of dissolving a lyophilisate (a dry peptide powder) in an appropriate solvent — most often bacteriostatic water or sterile water — before use in an experiment. It requires careful introduction of the solvent down the wall of the vial, without vigorous shaking, so as not to damage the molecule. After reconstitution the solution is stored under refrigerated conditions. It is also referred to as dissolving.

Research reagent

A chemical substance intended solely for laboratory and scientific applications (Research Use Only), not intended for diagnosis, therapy or human consumption. The status of a research reagent defines the legal framework for its trade and prohibits making claims about health applications. The peptides and SARMs in the One-Peptides catalogue function precisely as research reagents, not consumer products.

Rev-Erb

Nuclear receptors (Rev-Erbα/β) regulating circadian rhythm and metabolism. Activated by haem, they suppress the expression of biological-clock genes and participate in lipid and glucose metabolism. Rev-Erb agonists such as SR-9009 affect energy expenditure in animal models. Research concerns mainly chronobiology and metabolism; data involving humans remain limited.

RUO (Research Use Only)

The “research use only” designation — the status of a product intended for laboratory and scientific applications, not for clinical diagnosis, therapy or human consumption. RUO substances are not medicines or dietary supplements; making claims about health effects in humans is prohibited. This is the basic regulatory framework for the trade in peptides and SARMs intended for research.

S

SARM (selective androgen receptor modulator)

A class of compounds (Selective Androgen Receptor Modulators) that interact with the androgen receptor in a tissue-selective manner — in principle with a stronger effect on muscle and bone than on other tissues. Research examples: ostarine, RAD-140, ligandrol. No SARM is an authorised medicine, and these compounds are on the WADA list. Cardarine is sometimes mistakenly classed as a SARM, although it acts through PPARδ.

Secretagogue

A substance that stimulates the secretion of a particular hormone. In the context of research peptides, the term usually refers to growth hormone secretagogues (GHS) — compounds that stimulate the pituitary to release GH through the ghrelin or GHRH receptors. These include GHRP-2, GHRP-6, Ipamorelin, CJC-1295 and the oral MK-677. They act in a pulsatile manner, mimicking the physiological patterns of growth hormone secretion.

SR-9009 (Stenabolic)

A Rev-Erb receptor agonist, known in the research trade under the code “9009”. Studied in animal models for its effect on metabolism, endurance and circadian rhythm — it is sometimes classed among “exercise mimetics”. It is not a SARM or a hormone. The data come mainly from preclinical studies; oral bioavailability and the significance for human physiology remain limited.

 

Global disclaimer

The glossary is educational in character and organises scientific terminology. All the substances mentioned are chemical reagents intended solely for laboratory research (Research Use Only) — they are not medicines, dietary supplements or products for human consumption. The definitions describe molecular mechanisms and analytical concepts, do not constitute medical, pharmaceutical or dietary advice, and do not relate to the use of substances in humans.