Glossary

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A molecule that binds a receptor and triggers its signalling chain. Opposite: antagonist.

An agonist binds to a receptor and activates the signalling chain linked to it, similar to a key unlocking a lock. The counterpart is an antagonist: it also binds the receptor but does not trigger a signalling chain, instead occupying the site and blocking an agonist from binding. Studies use both roles to probe receptor signalling pathways in a targeted way.

An aliquot is a small, measured portion taken from a larger laboratory solution, usually stored separately.

Rather than repeatedly thawing and refreezing a whole reconstituted solution, laboratories divide it into several aliquots. Each portion is withdrawn and used on its own while the remaining portions stay sealed. This reduces temperature cycling and contamination risk for the rest of the volume.

Auch: Aminosäuren

The basic building block that peptides and proteins are assembled from via peptide bonds.

An amino acid is a small molecule with an amino group and a carboxyl group. When several link together via peptide bonds, a chain forms that becomes a peptide or a protein depending on its length. Twenty different amino acids occur naturally in the construction of peptides and proteins, and their order in the chain is called the sequence.

Auch: Analoga

A synthetically modified variant of an endogenous peptide with a slightly altered structure.

An analogue is a lab-made variant of a naturally occurring peptide in which individual amino acids have been swapped, added or removed. Researchers use such structural changes to study properties like stability or receptor binding behaviour in a targeted way. One example is semaglutide, an analogue of the endogenous hormone GLP-1.

Auch: AMPs, Wirtsabwehrpeptide

Antimicrobial peptides are part of innate immune defence, produced in skin and mucous membranes.

Antimicrobial peptides, also called AMPs or host defence peptides, are part of innate immune defence. They are produced by skin and mucosal cells as well as immune cells and insert into the membranes of bacteria, fungi or viruses. The best-known human group is the cathelicidins, whose only active human form is LL-37. Beyond this direct membrane mechanism, AMPs are also studied as immune system signalling molecules.

Auch: Anti-Obesity Drug 9604, Tyr-hGH Frag 177-191

A peptide fragment of human growth hormone (amino acids 177-191) studied for a fat-reducing effect without the growth-promoting effects of the full hormone.

AOD-9604 is a synthetic 16-amino-acid fragment of human growth hormone (sequence Tyr-hGH177-191), originally developed by Metabolic Pharmaceuticals in collaboration with Monash University for weight regulation. It was studied in six randomized, placebo-controlled human trials with more than 900 participants for its metabolic effects and safety. Clinical development as an obesity compound was discontinued in 2007 after the largest trial did not meet its primary efficacy endpoint.

Auch: Medikament

A medicinal product is legally defined as a substance intended to treat or prevent disease in humans.

Classification as a medicinal product determines whether marketing authorisation, a manufacturing licence and, where applicable, a prescription requirement apply. Products sold as research chemicals under an RUO label are not authorised as medicinal products and may not be advertised as such.

Auch: BAC-Wasser

Bacteriostatic water is sterile water with a preservative, usually benzyl alcohol, for solutions used more than once.

The added preservative, typically 0.9 per cent benzyl alcohol, inhibits bacterial growth in an opened solution. This lets a vial be used across several withdrawals in the lab instead of being discarded after a single use. Where no preservative is tolerated, sterile water without additives is used instead.

Auch: Peptid-Bioregulatoren, Khavinson-Peptide

Bioregulators are very short synthetic peptides of two to four amino acids studied at organ systems.

Bioregulators are a class of very short peptides, usually two to four amino acids long, developed at a Soviet institute for gerontology in the 1970s. The underlying hypothesis is that such short sequences interact with gene regulation in an organ-specific way. A well-known example is the tetrapeptide epitalon, studied in ageing research. The evidence base comes largely from Russian-language publications.

The proportion of a substance that reaches the bloodstream unchanged and can be measured there.

Bioavailability indicates what proportion of an administered substance ultimately reaches systemic circulation unchanged, measured as a percentage. It depends partly on how much the substance is broken down by enzymes, such as through proteolysis, on its way through the body. Pharmacokinetic studies determine bioavailability separately for different routes of administration.

In a blind test, a sample is sent to a lab with no indication of the manufacturer or shop, so the result stays unbiased.

Because the lab does not know the origin or sender, a possible bias in the result can be ruled out. A blind test checks the actual content of one specific sample, not the origin or authenticity of the batch itself.

Auch: Body Protection Compound 157, PL 14736

A synthetic peptide studied mainly in preclinical models of tissue regeneration.

BPC-157 is a synthetic pentadecapeptide whose sequence is derived from a protective protein found in human gastric juice. It is among the most studied peptides in tissue regeneration research, with a broad base of animal studies and a limited number of small human studies. Research focus areas include tendons, ligaments, the gastrointestinal lining, and wound healing.

Auch: AM833, NN9838

A long-acting analogue of the body's own hormone amylin, studied in clinical trials for metabolic and satiety regulation, alone and in combination with semaglutide.

Cagrilintide is a long-acting amylin analogue developed by Novo Nordisk. It is being studied both as a standalone substance and in a fixed combination with the GLP-1 compound semaglutide, marketed under the name CagriSema, in phase 3 trials. To date, cagrilintide is not approved as a standalone medication in any country.

Auch: Batch, Los

A batch is a single production run with its own batch number, the one a CoA actually refers to.

The batch number links one particular vial to the matching report, which is what makes a result traceable. A CoA with no clear batch reference cannot be tied to an actual product and says correspondingly little.

A chromatogram is the graphical output of an HPLC run, where each peak represents one component of the sample.

The area under the main peak gives the stated purity value, while smaller peaks represent impurities or degradation products. Without an additional identity check, the chromatogram alone does not show which molecule the main peak actually is.

Auch: Mod GRF 1-29, Modified GRF (1-29), CJC-1295 mit DAC, DAC:GRF

A synthetic analog of growth hormone-releasing hormone, studied in two variants with different durations of action.

CJC-1295 is a stabilized analog of the body's own GHRH, studied in the context of the growth hormone axis. It exists in two variants: without DAC (Drug Affinity Complex), which has a short duration of action, and with DAC, which achieves a substantially extended duration through binding to serum albumin. Available human data come mainly from early clinical research in healthy adults.

Certificate of Analysis

Auch: Analysezertifikat, Prüfbericht

A CoA is a report tied to a specific batch, listing batch number, test method and values such as purity or identity.

The value of a CoA depends on the batch number, since only that ties a report to one particular vial. A generic sample CoA with no link to a real batch says little about the actual product. Common entries include purity, identity and sometimes an endotoxin value.

Evidence coverage shows how many of the five score criteria are documented for a vendor.

Because missing criteria are omitted from the score calculation and the remaining weights redistributed, a single documented criterion alone can already produce a high value. Vendors with different evidence coverage are therefore only partly comparable. The number of documented criteria is shown next to the score.

Auch: PNB-0408, N-Hexanoyl-Tyr-Ile-(6)aminohexanamid

A synthetic angiotensin IV analog studied in preclinical rat models of memory function, with no published human data to date.

Dihexa is a synthetic peptidomimetic derived from the body's own angiotensin IV, developed in Joseph Harding's research group at Washington State University. To date it has been studied exclusively in preclinical models, mainly rats, in connection with learning and memory performance. No published human studies exist for dihexa, so its safety profile in humans has not been examined.

The documentation score shows how many verified vendor claims are actually documented.

The score combines five weighted criteria: lab 25 percent, legal framework 25 percent, shipping 15 percent, range 15 percent and price 20 percent. Missing criteria are not counted as zero points, they are omitted and the remaining weights are redistributed. It is not a quality seal or a legal assessment.

Auch: Doppelverblindung, doppelblind

A study design where neither participants nor staff know who gets the active substance or placebo. Reduces unconscious bias.

In a double-blind trial, the assignment to the treatment or control group is hidden from both participants and the study staff treating them. This prevents expectations on either side from influencing the result or its assessment. Together with randomisation and placebo control, double blinding counts as a strong quality marker.

Auch: Externes Labor

A third-party laboratory is an external lab that tests and documents a sample independently of the manufacturer or shop.

If a CoA names an external lab, it is worth checking whether the name is verifiable at all and whether it holds accreditation such as ISO 17025. A blind test is one way to check a result independently on top of that.

Auch: Delta Sleep Inducing Peptide, Delta Sleep Peptide

One of the longest-studied neuropeptides, originally isolated as a sleep-inducing messenger from the brain of sleeping rabbits, with an inconsistent body of research to this day.

DSIP (delta sleep-inducing peptide) is a nonapeptide first isolated in 1977 by Schoenenberger and Monnier from the venous brain blood of sleeping rabbits and named for its ability to trigger delta-wave EEG activity in that animal model. Over the following decades it was studied in numerous human trials on sleep, the stress axis, and hormone regulation. The originally described sleep-promoting effect has not been reliably reproduced in independent, more rigorous studies.

European Medicines Agency

The EMA is the EU agency that coordinates and assesses centralised marketing authorisation procedures.

The European Medicines Agency, based in Amsterdam, coordinates the scientific assessment of medicines seeking EU-wide authorisation and publishes the related assessment reports. The EMA has no role for research chemicals without an authorisation application and does not test individual batches.

Endotoxins are bacterial cell wall components, with the amount in a sample usually stated in units per milligram.

The value is a separate test point alongside purity and identity, and is usually listed on its own in a CoA. It is typically measured with the LAL test, an established method for detecting endotoxins in laboratory practice.

Auch: Epithalon, AEDG-Tetrapeptid

A synthetic tetrapeptide, studied in aging research as a research substance related to cellular aging.

Epitalon is a synthetic tetrapeptide developed by Vladimir Khavinson at the Saint Petersburg Institute of Bioregulation and Gerontology. It is studied in preclinical research in connection with cellular aging and the regulation of telomerase activity. Robust clinical data in humans is still pending.

Auch: Case Report

A detailed account of a single, often unusual case. Provides an early lead but no statistical evidence.

A case report describes observations in a single person or a small group of cases, often an unusual reaction or a rare event. It can prompt further research, but it has no control group and no statistical analysis. A case report alone does not prove a general effect.

Food and Drug Administration

The FDA is the US agency that authorises medicines, food and medical devices in the United States.

The Food and Drug Administration reviews marketing applications, oversees the US market and publishes warning notices about products. Its decisions apply to the United States and do not carry over to the EU. Peptides traded as research chemicals are not subject to an FDA authorisation procedure.

A short section of a larger endogenous peptide or protein, synthetically reproduced.

A fragment covers only a section of the original amino acid chain of a peptide or protein, not the full sequence. Such partial sequences are synthesised to study which part of a chain is responsible for particular properties, such as receptor binding. One known example is thymosin alpha-1, a fragment of a larger precursor protein.

A counter ion is a peptide's salt partner, usually trifluoroacetate (TFA) or acetate, left over from manufacturing.

Peptides are rarely supplied as the pure substance alone, but usually as a salt form with a bound counter ion. This share counts toward the total weight of the powder, which lowers the calculated net peptide content. TFA and acetate salts are the most common forms.

Auch: Glycyl-L-Histidyl-L-Lysin-Kupfer, Kupfertripeptid-1

A naturally occurring copper-binding tripeptide, studied most extensively in skin research, with additional preclinical data on other tissues.

GHK-Cu is a three-amino-acid tripeptide that occurs naturally in the body and stably binds a copper ion. It is studied mainly in cosmetic and dermatological research on collagen formation and skin renewal. Further, mostly preclinical research looks at possible effects on inflammatory processes and gene expression across various tissue models.

Growth hormone-releasing hormone

Auch: Somatoliberin

GHRH is a hypothalamic hormone that triggers the pituitary gland to release growth hormone.

Growth hormone-releasing hormone is a hypothalamic peptide that travels via the pituitary portal system to the pituitary gland, where it triggers growth hormone release from somatotroph cells. It is part of the growth hormone axis and is the counterpart to the body's own inhibitor, somatostatin. Several synthetic GHRH analogues bind the same receptor and are studied or used in this context.

Growth hormone-releasing peptide

Auch: GH-Sekretagoga, Wachstumshormon-Sekretagoga

GHRPs are synthetic peptides that trigger growth hormone release through the ghrelin receptor.

Growth hormone-releasing peptides are a class of synthetic peptides that bind the ghrelin receptor (GHS-R) to trigger growth hormone release from the pituitary gland. Unlike GHRH analogues, they use a separate signalling pathway and are often combined with GHRH analogues in research. The ghrelin receptor is also involved in regulating hunger and appetite.

Glucose-dependent insulinotropic polypeptide

GIP is a gut hormone that regulates insulin release after carbohydrate-rich meals.

Glucose-dependent insulinotropic polypeptide is the second major incretin hormone alongside GLP-1. K cells in the upper small intestine release it after eating, and it binds the GIP receptor to regulate insulin release. It is also involved in fat metabolism. Several newer diabetes and obesity compounds combine GIP with GLP-1 receptor agonism.

Glucagon-like peptide 1

Auch: Glucagon-ähnliches Peptid 1

GLP-1 is a gut hormone released after eating that regulates insulin release.

Glucagon-like peptide 1 is an incretin hormone released by L cells in the small intestine after eating. It binds the GLP-1 receptor, regulates insulin release, slows gastric emptying and is involved in satiety signalling in the brain. Several synthetic GLP-1 receptor agonists target this system, and some are approved as medicines.

Good Manufacturing Practice

GMP is a recognised quality standard for manufacturing medicinal products and similar goods.

Good Manufacturing Practice covers requirements for facilities, processes, documentation and traceability in production. GMP is mandatory mainly for authorised medicinal products. A manufacturer's GMP claim does not replace independent evidence such as a public CoA and applies only insofar as it is documented.

The time it takes for a substance's concentration in the body to drop by half.

Half-life describes how long it takes for a peptide's blood concentration to fall to half its starting value. It is measured in pharmacokinetic studies and varies considerably between individual peptides, partly depending on how quickly endogenous enzymes break down the chain through proteolysis. A shorter half-life means faster breakdown compared with a longer one.

A synthetic hexapeptide from the growth hormone-releasing peptide class, studied in early clinical research on growth hormone secretion.

Hexarelin is a synthetic hexapeptide from the GHRP (growth hormone releasing peptide) class, first pharmacologically described in 1994. It has been studied in clinical trials on growth hormone secretion in children, adults, and older adults, and separately in preclinical research on cardiac effects.

High-performance liquid chromatography

Auch: Hochleistungsflüssigchromatografie

HPLC is the standard analytical method used to determine a peptide sample's purity as a percentage.

The method separates a sample into its components and measures each one, producing a chromatogram with one peak per component. The area of the main peak gives the stated purity value. HPLC alone says nothing about identity, that requires mass spectrometry as well.

Therapeutic Products Advertising Act

The HWG regulates advertising of medicinal products and therapeutic methods to the public in Germany.

The German Therapeutic Products Advertising Act restricts how medicinal products and treatment methods may be described publicly, including claims about disease or human use. This is why Peptide Compass describes substances only in terms of research findings and makes no statements about an effect in the reader's body.

Identity, confirmed by mass spectrometry, verifies that a sample actually contains the stated peptide.

It is usually shown via LC-MS, a combination of liquid chromatography and mass spectrometry that measures molecular weight. Purity and identity are two separate figures, and a complete CoA lists both. Purity alone does not prove which molecule is actually present.

Insulin-like growth factor 1

Auch: Somatomedin C

IGF-1 is a hormone produced mostly in the liver in response to growth hormone.

Insulin-like growth factor 1 is produced mainly in the liver, triggered by growth hormone binding to liver cells, and circulates in the blood largely bound to carrier proteins. It binds the IGF-1 receptor and mediates much of growth hormone's effect on muscle, bone and connective tissue. An IGF-1 analogue with an extended half-life is used in research as a standalone tool, independent of the body's own regulation via growth hormone.

Auch: Long R3 IGF-1, LR3-IGF-1, IGF-1 Long R3

A genetically lengthened analogue of IGF-1 with 83 amino acids, studied in animal models for growth effects and listed as a doping substance in competitive sport.

IGF-1 LR3 is a recombinant analogue of the naturally occurring insulin-like growth factor 1, originally developed for cell-culture research. It carries additional amino acids at the N-terminus and an altered position 3, which makes it largely unable to bind IGF-binding proteins. It is studied mainly in animal models of organ and cell growth, but outside research it is also widely used for purported performance enhancement without solid human data.

Auch: in vitro

A test outside a living organism, usually on cell cultures. It says nothing about an effect in humans.

In vitro studies examine isolated cells or molecules in a controlled setting such as a petri dish. They can show early biochemical effects, but the cell context does not replace a whole organism. This kind of data counts as lab research only and does not translate to humans.

Auch: in vivo

A test inside a living organism, usually an animal model. Closer to reality than a cell culture, but still no proof for humans.

In vivo studies observe a whole organism with metabolism, immune system and organs, usually an animal model. This gives more realistic clues than a cell culture. Because metabolism and physiology differ, animal results do not transfer directly to humans.

Auch: Inkretinhormone

Incretins are gut hormones released after eating that are involved in regulating insulin release.

Incretins are a hormone class from the gut that includes GLP-1 and GIP. They are released from specialised gut cells after eating and bind their own receptors on pancreatic beta cells. Through this mechanism, insulin release after oral glucose intake is higher than after an intravenous dose of the same amount, an effect known as the incretin effect. Several approved and investigational medicines mimic this pathway.

Auch: NNC 26-0161

A selective pentapeptide from the growth hormone-releasing peptide class, studied in early clinical research.

Ipamorelin is a synthetic peptide made up of five amino acids that mimics the body's own messenger ghrelin. It was first described in 1998 as the first selective member of its drug class and has been studied in clinical trials including in patients recovering from abdominal surgery. For growth hormone-related applications, no controlled studies in healthy adults are available to date.

ISO/IEC 17025

ISO 17025 is the international standard for the technical competence of testing and calibration laboratories.

Accreditation under this standard means a lab's procedures, equipment and staff were independently assessed. It is a quality marker for the laboratory itself, not a guarantee for any one specific CoA result.

International Unit

Auch: IE

The International Unit measures a substance's biological potency against a reference standard, not its weight.

For substances such as growth hormone, weight alone does not describe the amount meaningfully, because different batches can vary in purity at the same weight. The International Unit instead sets the amount in relation to a defined WHO reference preparation. One milligram of one hormone therefore does not automatically equal the same number of units as one milligram of a different preparation.

Auch: Metastin (45-54), KP-10

The shortest bioactive fragment of the body's own kisspeptin system, studied in endocrine research on control of the hypothalamic-pituitary-gonadal axis.

Kisspeptin-10 is the shortest fragment of the body's own peptide kisspeptin (metastin) that retains full activity at the KISS1R receptor. In research it is used to trigger GnRH release directly and to study the hypothalamic-pituitary-gonadal axis in questions of pubertal development, hypogonadism, and fertility. Larger clinical trials on endpoints such as oocyte maturation or sexual arousal mostly used the longer natural isoform kisspeptin-54, which acts on the same receptor.

Auch: klinische Prüfung

A study in human participants, usually structured in phases I to III. The most informative study type for humans.

A clinical trial tests a substance in human participants for the first time or at a later stage, typically following phases I to III. It follows a fixed protocol with inclusion and exclusion criteria and ethical approval. Of the study types, it provides the most reliable data, but it does not replace individual medical advice.

Concentration states how much of a substance is dissolved in a given volume of liquid, usually in mg per ml.

After reconstituting a lyophilised peptide, the concentration follows from the weighed powder amount divided by the liquid volume added. A figure of 5 mg per ml means each millilitre of the solution contains 5 milligrams of dissolved substance. This figure is a plain calculation and independent of any particular use.

Auch: Lys-Pro-Val, alpha-MSH(11-13)

A three-amino-acid fragment of alpha-MSH, studied in animal models for anti-inflammatory properties in the gut and on the skin.

KPV is a tripeptide made of the amino acids lysine, proline, and valine, derived from the C-terminal end of the hormone alpha-MSH. It is among the smallest peptides studied in inflammation research, with a focus on animal models of chronic inflammatory bowel disease and skin inflammation. Human studies are not yet available.

Auch: GHK-Cu-Komplexe

Copper peptides are complexes of a small peptide and a copper ion, the best known being GHK-Cu.

Copper peptides are compounds in which a small peptide coordinates a copper ion. The best-known example is GHK, a three-amino-acid peptide found in human blood plasma, saliva and urine, where it naturally occurs bound to copper. In its copper-complex form, GHK-Cu is studied mainly in skin research, with additional preclinical data on connective tissue and wound healing.

Storage describes how a peptide is kept before use, usually cool, dry and dark depending on its state.

Lyophilised powder stays considerably more stable under cool, dark and dry storage than a reconstituted solution does. Manufacturers state specific temperature ranges on the label or datasheet, and storage follows those figures. Heat, moisture and light are the three factors that change a sample's condition over time the most.

Light protection covers measures that shield a sample from light exposure, such as amber vials or storage in the dark.

Some peptides are sensitive to UV and visible light, which can encourage breakdown of the molecular structure over time. Amber glass vials, light-blocking outer packaging or storage in a closed drawer are common light-protection measures in the lab. Combined with cool storage, these give lyophilised material its longest stability.

Auch: Cathelicidin, hCAP18(134-170), Human Cathelicidin

A naturally occurring antimicrobial peptide made of 37 amino acids that protects skin and mucous membranes, studied in clinical trials for wound healing.

LL-37 is the only known member of the cathelicidin peptide family in humans and is produced by immune cells as well as skin and mucosal cells in response to injury or infection. It is generated by cleavage from the precursor protein hCAP18. Clinical research has focused mainly on topical application for hard-to-heal wounds, such as venous leg ulcers and diabetic foot ulcers.

Lyophilisate is the freeze-dried powder form of a peptide, the most stable storage form before reconstitution.

Lyophilisate is produced when a dissolved peptide sample is frozen and then dried under vacuum in the laboratory, so the water passes directly from a solid to a gas. The result is a powder or a loose cake inside the vial. In this form a peptide stays stable for much longer than in solution and is only reconstituted shortly before use.

Auch: MS

Mass spectrometry determines a sample's molecular weight and so confirms which molecule is actually present.

Combined with liquid chromatography (LC-MS), it verifies a peptide's identity independently of its purity value. A high purity value without this check says nothing about whether the correct molecule is present at all.

Auch: Melanocortin-System

Melanocortins are peptide hormones derived from POMC that bind five receptor types regulating skin, appetite and sexual response.

Melanocortins are a family of peptide hormones derived from the precursor protein proopiomelanocortin (POMC), including alpha-MSH and ACTH. They bind five distinct melanocortin receptors (MC1R to MC5R) that regulate skin pigmentation, appetite, energy balance, inflammatory processes and sexual response, among other functions. Synthetic melanocortin receptor agonists target individual receptors within this system.

Auch: MT-2, MT2

A synthetic analog of the body's own hormone alpha-MSH, studied in early clinical trials on pigmentation and sexual function.

Melanotan II is a synthetic, cyclic seven-amino-acid peptide that binds several melanocortin receptors in the body. It was developed in the 1980s at the University of Arizona and is considerably more potent than its natural counterpart, alpha-MSH. Areas of study include a role in skin pigmentation as well as sexual desire and arousal.

A statistical pooling of multiple individual studies on one question. Gives a more reliable picture than a single study.

A meta-analysis pools the data of several already published studies on the same topic and evaluates them together using statistical methods. This increases the participant count and evens out random variation between individual studies. The reliability of a meta-analysis depends heavily on the quality and comparability of the included studies.

One milligram equals 1000 micrograms, the standard mass unit for small peptide amounts on labels and CoAs.

Milligrams (mg) and micrograms (µg) are both subunits of the gram and differ by a factor of 1000. Vial labels and CoAs usually state the peptide amount in milligrams, while individual component figures sometimes appear in micrograms. The calculator on this page converts between grams, milligrams and micrograms on a purely mathematical basis.

Auch: Mitochondrien-Peptide

Mitochondrial peptides target cellular energy production or originate from mitochondrial DNA.

Mitochondrial peptides are not a single substance class in the classical sense. The term groups together peptides that either bind at the inner mitochondrial membrane or are encoded by mitochondrial rather than nuclear DNA. The second group includes a short peptide derived from the mitochondrial 12S rRNA gene, studied in metabolic research. Another example binds cardiolipin in the inner membrane and is used in research on cellular ageing and energy metabolism.

Auch: Mitochondrial-Derived Peptide MOTS-c, Mitochondrial Open Reading Frame of the 12S rRNA Type-c

A mitochondrially encoded peptide studied as an exercise mimetic in metabolic research.

MOTS-c is a 16-amino-acid peptide encoded directly in mitochondrial DNA rather than in the cell nucleus. It was discovered in 2015 and is studied as an endogenous signaling molecule that is released in greater amounts during physical exertion. Research focuses on possible effects on insulin sensitivity, fat metabolism, and cellular aging.

A peptide that acts as a signalling molecule between cells in the nervous system.

Neuropeptides are peptides released by nerve cells that act as signalling molecules within the nervous system. They differ from classic neurotransmitters in their larger molecular structure and also bind to specific receptors on target cells. In research, neuropeptides are used among other things to map signalling pathways in the central nervous system.

Auch: Smart Drugs

Nootropics are a broad substance class studied in relation to memory, learning or stress processing.

Nootropics is an umbrella term for a very heterogeneous substance class ranging from vitamins to plant extracts to synthetic peptides, studied in relation to memory, learning ability, attention or stress processing. Within peptide research, this includes ACTH-derived fragments and tuftsin analogues, among others. The term was coined in 1972 by Romanian chemist Corneliu Giurgea. Most peptide nootropics are supported mainly by preclinical and Russian-language data so far.

Di-, tri- and oligopeptide

Auch: Dipeptid, Tripeptid

A short amino acid chain, classified by length as di-, tri- or oligopeptide.

Chain length sets the name at the shorter end of the scale. Two amino acids form a dipeptide, three a tripeptide. Chains of up to roughly ten amino acids are generally called oligopeptides. From around ten up to roughly 50 amino acids, the term is polypeptide, and beyond that, once the chain has a fixed three-dimensional shape, it becomes a protein.

Auch: OXT, Pitocin

An endogenous nonapeptide hormone, approved as a medication to induce labor and also studied in research on social behavior and bonding.

Oxytocin is a nine-amino-acid hormone produced in the hypothalamus and released via the pituitary gland. As a medication, such as Syntocinon or Pitocin, it is approved to induce labor and control postpartum bleeding. Separately, intranasally administered oxytocin is studied in basic research on social behavior, trust, and bonding.

A partner code is the discount code our partners honour for you; currently peptidecompass10.

The code is entered at the respective shop's checkout and, according to the vendor, may unlock a discount. Its size and terms are set by the vendor and are not always documented here. On purchases attributed through the code, Peptide Compass may receive a commission, without this affecting the documentation score.

Expert review of a study manuscript by independent specialists before publication.

In peer review, independent experts check the methodology, data analysis and conclusions of a manuscript before publication. They can request corrections or reject the work. A peer-reviewed publication is considered more trustworthy than an unreviewed text, though it is no guarantee against error.

Auch: PDA, BPC-157 Arginat-Salz

A pentadecapeptide sharing the amino-acid sequence of BPC-157, offered as an arginine salt for improved solubility and stability.

Pentadeca Arginate, often abbreviated PDA, carries the same 15-amino-acid sequence as the well-known peptide BPC-157. The difference lies in the counter-ion: instead of an acetate salt, the sequence is bound to arginine, which suppliers describe as improving solubility and shelf stability. Independent studies examining this specific salt form are not yet available.

Auch: Peptide

A short chain of amino acids linked by peptide bonds.

A peptide is made up of several amino acids strung together by peptide bonds. Two amino acids form a dipeptide, three a tripeptide, and up to roughly 50 is called a polypeptide. Above 50 amino acids, once the chain settles into a fixed three-dimensional shape, a peptide becomes a protein. Peptides sit on the same scale as proteins, just smaller and often still unfolded.

The chemical link that joins two amino acids into a chain.

A peptide bond forms when the carboxyl group of one amino acid reacts with the amino group of the next, releasing a water molecule in the process. This link repeats along the entire chain and forms the backbone of peptides and proteins. The order of the amino acids joined this way sets the sequence.

Net peptide content states what share of a powder's mass is actually the peptide itself.

The rest of the mass is usually moisture, salts and the counter ion. A powder can show a high HPLC purity value and still have a lower net peptide content, because purity only describes the ratio within the chromatogram, not the total weight of the sample.

A hormone the body produces that is chemically an amino acid chain.

A peptide hormone is a signalling molecule built from a chain of amino acids, unlike steroid hormones, which are based on cholesterol. Peptide hormones are produced in glands or specialised cells and bind to receptors on target cells. Insulin is a well-known example of an endogenous peptide hormone.

Auch: Scheinpräparat

A dummy preparation with no active ingredient, used to compare against a real substance in a trial. Separates real from expected effects.

A placebo looks like the tested preparation but contains no active ingredient. In a study design it serves as the comparison group, showing how much of a response comes from participant expectation rather than the substance itself. Placebo control is a core feature of informative clinical trials, often combined with blinding.

Auch: Präklinik

The research stage before any human use: cell culture and animal model. Clinical trials follow only after this stage.

Preclinical research covers in vitro and in vivo experiments that check early effects and safety before a substance is ever tested in humans. It provides the data basis for a possible later clinical trial. A preclinical result alone does not support a claim about humans.

Price per milligram makes offers with different pack sizes directly comparable.

The figure is the list price divided by the milligram content of a product, compared for the same active substance and currency. Shipping, availability and discount terms are included only when explicitly documented. A lower figure says nothing about purity or documentation.

A study manuscript published before peer review. Results count as preliminary, not yet independently checked.

A preprint is published on an open platform before a journal has reviewed it. This speeds up the exchange of results but means the methodology and conclusions have not yet been independently checked. Content from a preprint should be judged more cautiously than a peer-reviewed publication.

Auch: Eiweiß

A long amino acid chain with a fixed three-dimensional shape, larger than a peptide.

Like a peptide, a protein is made of amino acids linked by peptide bonds, but it is substantially longer, usually above 50 amino acids, and folds into a fixed three-dimensional shape. That folding is what sets a protein apart from a peptide, which is often still unfolded. Both terms describe points on the same size scale rather than a fundamentally different molecule.

The enzymatic breakdown of an amino acid chain into smaller fragments.

Proteolysis is the process by which enzymes called proteases cleave the peptide bonds in an amino acid chain, breaking it into smaller fragments. This breakdown happens continuously in the body and affects how long a peptide stays intact, in other words its half-life. Studies often report proteolytic stability as a measure of a peptide's durability.

Auch: Bremelanotide, Vyleesi

A synthetic heptapeptide and melanocortin receptor agonist, approved in the US under the name Vyleesi for a specific form of low sexual desire in women.

PT-141 (bremelanotide) is a seven-amino-acid peptide developed at Palatin Technologies as a follow-on compound to melanotan II. Unlike melanotan II, which was studied mainly for skin pigmentation, research on bremelanotide focused on the central regulation of sexual desire. Since 2019, the compound has been approved in the US under the name Vyleesi for the indication hypoactive sexual desire disorder (HSDD) in premenopausal women.

A free database run by the US National Library of Medicine for biomedical literature.

PubMed indexes millions of articles from medicine and life sciences and usually shows a free abstract directly. The full text often sits behind the respective journal's paywall. A PubMed listing confirms that a paper is indexed, but it says nothing about the quality of that individual study.

Randomised controlled trial

A study design with random assignment to a treatment and a control group. Considered the gold standard for proving an effect.

In a randomised controlled trial, participants are assigned by chance to a treatment or a control group, often blinded as well. This reduces bias from expectation or selection. RCTs are considered the methodological gold standard in clinical research, especially combined with placebo control.

Purity states how much of a sample's chromatogram peak area belongs to the main molecule, usually as a percentage from HPLC.

The figure shows how clean a sample is relative to by-products and impurities, not how much peptide it actually contains, that question is answered by net peptide content instead. A high purity value without an identity check also says nothing about whether the correct molecule is present.

Reconstitution is dissolving a lyophilised peptide in a liquid to prepare a solution for laboratory use.

During reconstitution, the freeze-dried powder in the vial is combined with a liquid, usually bacteriostatic or sterile water, until the peptide has fully dissolved. The concentration of the finished solution follows from the powder amount and the liquid volume added. Stability drops noticeably once dissolved, which is why cooling and light protection matter more. The calculator on this page covers plain mass-unit conversion.

Auch: LY3437943

A peptide that acts on GLP-1, GIP, and glucagon receptors simultaneously, currently in advanced clinical trials related to metabolic regulation.

Retatrutide is a so-called triple agonist that acts on three metabolic receptors simultaneously: GLP-1, GIP, and glucagon. It is currently in phase 3 trials and is not approved as a medication in any country to date.

A protein on or inside a cell that a peptide binds to specifically.

A receptor is a protein that specifically recognises and binds a matching molecule, such as a peptide, similar to a lock and key. This binding triggers a signalling chain inside the cell. In research, how strongly a peptide binds to a given receptor is called affinity and is often studied in the lab using cell cultures.

A prescription requirement means a medicinal product may only be dispensed against a doctor's prescription.

Whether an authorised medicinal product requires a prescription is decided by the responsible authority based on its risk profile, such as dosage, side effects or potential for misuse. This classification applies to authorised medicinal products. Substances sold as unauthorised research chemicals have no corresponding regulatory classification.

Research Use Only

RUO labels a product as a research chemical, not authorised for human use.

RUO stands for Research Use Only, a labelling convention from laboratory supply. It shows that a vendor offers the product for research purposes only and that no marketing authorisation as a medicinal product exists. The label does not replace quality testing and is not proof of purity or identity.

A synthetic heptapeptide analog of the body's own tuftsin, studied in research on anxiety regulation and cognitive function.

Selank is a heptapeptide derived from the body's own tetrapeptide tuftsin, originally developed in Russia as an anxiolytic. Research links it to anxiety-regulating and mildly cognition-supporting effects, without the sedation typical of benzodiazepines.

A GLP-1 receptor agonist, known as an approved medication and listed here as a research substance for metabolic regulation.

Semaglutide is a GLP-1 receptor agonist approved as a medication under several brand names. It is the subject of extensive clinical research on metabolic and satiety regulation. The research batches listed here are not equivalent to approved medications and are intended for laboratory use only.

A synthetic ACTH-derived heptapeptide, approved in Russia for neuroprotection and studied in research on cognition and stress adaptation.

Semax is a heptapeptide derived from the ACTH(4-10) fragment of the stress hormone ACTH, approved as a medication for ischemic stroke in Russia. Research also examines it in relation to neuroplasticity and cognitive function, without activating the cortisol axis.

Auch: Aminosäuresequenz

The fixed order of amino acids in a peptide or protein chain.

The sequence describes the order in which the individual amino acids are strung together via peptide bonds. It is usually written using standardised one- or three-letter codes per amino acid. Two peptides made of the same amino acids but in a different order count as different molecules, which makes the sequence a key identity marker.

Auch: GRF 1-29, GHRH(1-29), Geref (historischer Markenname)

A short-chain fragment of the body's own GHRH, historically approved as a medication, now sold as a research substance.

Sermorelin is the biologically active fragment GHRH(1-29) of the body's own growth hormone-releasing hormone. In the US it was approved in 1990 as a diagnostic agent and in 1997 for growth hormone deficiency-related short stature in children; the approval was withdrawn in 2008 for manufacturing reasons. Today it is studied outside that historical approval as a research substance.

Auch: Elamipretide, MTP-131, Bendavia

A mitochondria-targeted tetrapeptide studied in several clinical trials for heart failure and mitochondrial disease, not yet approved.

SS-31, also known under the generic name elamipretide as MTP-131 or Bendavia, is a synthetic tetrapeptide that binds specifically to cardiolipin, a lipid in the mitochondrial membrane. It has been studied in several phase 1 to phase 3 clinical trials for heart failure, primary mitochondrial myopathy, and Barth syndrome. Despite a comparatively broad clinical data base, none of these studies has yet led to approval as a medication.

Sterile water is germ-free water with no preservative, intended for single use per vial.

Sterile water is cleared of micro-organisms through filtration or heat treatment and filled without further additives. Because it contains no preservative, it does not offer the extended growth inhibition that bacteriostatic water provides. An opened batch is therefore used promptly in the lab or discarded rather than kept for an extended period.

Sterility describes the absence of viable microorganisms in a sample, checked through its own dedicated lab test.

The test is independent of purity, identity and endotoxin value, and is documented separately. It matters mainly for lyophilised peptides that are dissolved and handled further in a laboratory setting.

Auch: Phase I bis IV

The four stages of clinical testing: phases I to III before approval, phase IV afterwards in everyday use.

Phase I mainly tests safety and tolerability in a small group of healthy volunteers. Phase II checks early signs of efficacy and dose ranges in a larger group. Phase III compares outcomes in many participants, often with placebo and blinding, before a possible approval. Phase IV monitors an already approved product in wide everyday use.

Auch: BI 456906

A peptide that acts on both GLP-1 and glucagon receptors simultaneously, currently in advanced clinical trials related to metabolic regulation.

Survodutide is a dual agonist at GLP-1 and glucagon receptors, developed by Boehringer Ingelheim in collaboration with Zealand Pharma. It is being studied in phase 3 trials for weight regulation in obesity as well as in metabolic dysfunction-associated steatohepatitis (MASH), and is not approved as a medication in any country to date.

Auch: Thymosin-Beta-4-Fragment, TB4 Frag

A synthetic fragment of the body's own protein thymosin beta-4, studied in preclinical research on cell migration and tissue regeneration.

TB-500 is the synthetically produced, seven-amino-acid core sequence of the body's own protein thymosin beta-4. Most available data, including clinical studies, relate to the full 43-amino-acid thymosin beta-4, not to the isolated TB-500 fragment itself. Areas of study include cell migration, angiogenesis, and a possible role in hair follicle activation.

Auch: Egrifta, TH9507, Egrifta WR

A stabilized GHRH analog, approved in the US as the medication Egrifta for reducing visceral abdominal fat in HIV-associated lipodystrophy.

Tesamorelin is a stabilized analog of the full 44-amino-acid GHRH. Under the brand name Egrifta, it has been approved by the US FDA since 2010 for reducing visceral abdominal fat in HIV-associated lipodystrophy. This makes it the only peptide in its class with a completed phase 3 approval study in more than 800 participants.

Auch: Tα1, Zadaxin (Handelsname)

A naturally occurring thymus-derived immune peptide, approved as a medication in more than 35 countries, though not currently in Germany, Austria, or Switzerland.

Thymosin alpha 1 is a 28-amino-acid peptide originally isolated from the thymus gland, the central organ where T cells mature. It acts as an immune modulator and is used both in clinical research and, under the trade name Zadaxin, as an approved medication for certain immune conditions. Areas of study include chronic viral infections, the immune response to vaccination, and a supportive role in oncology.

Auch: Thymosinpeptide

Thymosins are a family of peptides originally isolated from the thymus gland.

Thymosins are a family of small peptides originally isolated from the thymus and divided into two main groups: alpha thymosins, studied mainly in relation to the immune system, and beta thymosins, involved in organising the actin cytoskeleton. Several studied peptide fragments are derived from thymosin beta-4. Thymosin alpha 1 is approved as a medicine under the name Zadaxin in several countries.

A laboratory animal, such as a mouse or rat, used to study a substance in vivo. Not direct proof for humans.

An animal model is a laboratory animal such as a mouse, rat or zebrafish in which metabolism, behaviour or tissue is studied under controlled conditions. It serves preclinical research before a possible clinical trial. Because genetics and physiology differ, an effect in an animal model is not proof of an effect in humans.

Auch: LY3298176

A dual GIP/GLP-1 receptor agonist, known as an approved medication and listed here as a research substance for metabolic regulation.

Tirzepatide is a dual GIP/GLP-1 receptor agonist approved as a medication under the names Mounjaro and Zepbound. It is the subject of extensive clinical research on metabolic and weight regulation in type 2 diabetes and obesity. The research batches listed here are not equivalent to approved medications and are intended for laboratory use only.

U-100 describes a graduation scale that divides a volume into 100 equal units, 100 units per millilitre.

The designation U-100 comes from a graduation where each marker on the scale represents one hundredth of a millilitre, so 100 units correspond to one millilitre. This scale appears on correspondingly marked measuring aids and is used to read off small liquid volumes precisely. It is purely a unit of measurement and independent of the dissolved substance.

Auch: Fläschchen

A vial is a small glass container, usually sealed with a rubber stopper, holding a peptide as powder or solution.

Vials are the standard packaging for lyophilised peptides in the research trade. The rubber stopper allows a closed withdrawal, and the printed label usually carries the batch number and amount. A single vial can be matched to a CoA as long as the batch number lines up.

Somatotropin

Auch: GH, HGH, Somatotropin

Growth hormone is a pituitary hormone that regulates growth, metabolism and body composition.

Growth hormone, also called somatotropin or GH, is produced by somatotroph cells in the pituitary gland and released into the blood in pulses, controlled by GHRH, somatostatin and ghrelin. It regulates longitudinal growth, muscle and fat metabolism and bone density, both directly and via IGF-1 from the liver. Several peptide classes target different points along this axis, including release from the anterior pituitary.

World Anti-Doping Agency

WADA publishes an annual prohibited list for sport that also includes peptides.

The World Anti-Doping Agency coordinates anti-doping rules in organised sport and updates its prohibited list annually. Several categories cover peptide hormones and related substances, independent of their legal status outside sport. Which specific substance is covered is set out only in the current WADA list itself.

Auch: Marktzulassung

Marketing authorisation is the regulatory approval required to sell a medicinal product in a market.

Before authorisation, the responsible authority reviews submitted data on quality, safety and efficacy. In the EU, centralised procedures run through the EMA, national ones through bodies such as national medicines agencies. Substances traded only as research chemicals do not go through this procedure for that purpose.

Auch: 5-Amino 1MQ, 5A1MQ, NNMT-Inhibitor

A small molecule and selective inhibitor of the enzyme nicotinamide N-methyltransferase (NNMT), studied to date exclusively in preclinical animal models related to fat metabolism.

5-Amino-1MQ is not a peptide but a small molecule, a selective, orally bioavailable inhibitor of nicotinamide N-methyltransferase (NNMT). It has a molecular weight of 173.21 Da, and research batches sold commercially typically carry a purity of at least 98 percent. It is listed under the metabolism category because NNMT is involved in energy metabolism in adipose tissue and muscle. To date, only preclinical data from rodent models are available, and no controlled human studies are known.