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Research library

The science behind the compounds

Peer-reviewed research, mechanism breakdowns, and compound profiles for every peptide in our catalog. Built for researchers who want to understand what they're working with.

Looking for guides, definitions and calculators alongside the compound overviews? The Learn hub ties the research library, laboratory guides, glossary and tools together.

Evidence-based, not marketing-based

Every compound we carry has a documented research history. We don't add products to our catalog based on trends — we add them when the peer-reviewed literature supports their study.

The profiles below summarize published research on mechanism of action, studied applications, and relevant pharmacokinetics. They are not medical claims and are intended solely for researchers.

Stated purity≥99%
Compounds profiled32
LiteraturePubMed-cited

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32 compound overviews

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Compound profiles

Growth Hormone Peptides

Secretagogues and releasing hormones studied for their role in GH axis modulation.

GHRP · Stated purity ≥99% Ipamorelin Selective GH secretagogue that binds the ghrelin receptor (GHSR-1a) without significantly elevating cortisol or prolactin. Studied in: GH pulse amplification · Body composition research · Sleep-architecture research models Half-life: ~2 hours GHRH Analog · Stated purity ≥99% CJC-1295 w/ DAC Modified GHRH(1-29) with Drug Affinity Complex technology enabling albumin binding for extended half-life. Studied in: Sustained GH elevation · IGF-1 modulation · Body-composition research models Half-life: 6–8 days GHRH Analog · Stated purity ≥99% Tesamorelin Full-length GHRH analog with N-terminal trans-3-hexenoic acid modification for enhanced stability. Studied in: Adipose-tissue biology research · Metabolic syndrome research · Lipodystrophy models Half-life: ~26 minutes IGF-1 Analog · Stated purity ≥99% IGF-1 LR3 Arg3 substitution prevents IGFBP binding; 13 aa N-terminal extension enhances receptor affinity. Studied in: Anabolic signaling pathways · Satellite cell activation · Cellular proliferation models Half-life: 20–30 hours

Recovery Peptides

Compounds studied for tissue repair, inflammation modulation, and musculoskeletal recovery.

Pentadecapeptide · Stated purity ≥99% BPC-157 Derived from a protective protein in gastric juice; may upregulate GH receptor expression in fibroblasts. Studied in: Tendon-to-bone healing · Gut mucosal repair · Ligament repair mechanisms Half-life: ~4 hours Thymosin Beta-4 Fragment · Stated purity ≥99% TB-500 Actin-sequestering peptide that promotes cell migration, angiogenesis, and tissue remodeling. Studied in: Angiogenesis research · Cardiac tissue repair models Half-life: Days

Longevity & Metabolic

Mitochondrial and metabolic peptides studied for cellular energy, longevity pathways, and metabolic regulation.

Mitochondrial Peptide · Stated purity ≥99% MOTS-c Encoded in mitochondrial 12S rRNA; activates AMPK and regulates AICAR/ZMP metabolite levels. Studied in: Insulin sensitization · Exercise mimicry research · Metabolic flexibility models Half-life: ~2–4 hours Coenzyme · Stated purity ≥99% NAD+ Essential coenzyme in over 500 enzymatic reactions; substrate for sirtuins involved in longevity pathways. Studied in: Sirtuin activation · Mitochondrial biogenesis · Age-related metabolic decline Half-life: Intracellular ~1–2 hours Dual GLP-1/GIP Agonist · Stated purity ≥99% Tirzepatide Dual incretin receptor agonism targeting GIP and GLP-1 pathways for glucose-dependent insulin secretion. Studied in: Glucose homeostasis models · Appetite regulation research · Cardiovascular risk factor studies Half-life: ~7 days Mitochondria-Targeting Tetrapeptide · Stated purity ≥99% SS-31 Aromatic-cationic tetrapeptide (D-Arg-Dmt-Lys-Phe-NH2) that selectively partitions into the inner mitochondrial membrane and reduces cardiolipin peroxidation. Studied in: Cardioprotection models · Oxidative stress reduction · Mitochondrial bioenergetics Half-life: ~2 hours Triple GLP-1/GIP/Glucagon Agonist · Stated purity ≥99% Retatrutide Triple incretin receptor agonist simultaneously activating GLP-1R, GIPR, and glucagon receptor for additive metabolic effects. Studied in: Obesity and adiposity models · Glucose regulation research · Lipid metabolism studies Half-life: ~6 days

Cognitive & Other Research Compounds

Neuropeptides and melanocortin analogs studied for CNS modulation.

Tuftsin Analog · Stated purity ≥99% Selank Heptapeptide derived from tuftsin (Thr-Lys-Pro-Arg-Pro-Gly-Pro) with enhanced metabolic stability; modulates GABA-A receptor activity and BDNF expression. Studied in: Anxiolytic-like effects · BDNF modulation · Cognitive performance models Half-life: ~1–2 minutes (plasma); active metabolites persist longer α-MSH Analog · Stated purity ≥99% MT-1 Synthetic linear analog of α-melanocyte-stimulating hormone; potent agonist at MC1R and MC4R with enhanced receptor binding affinity. Studied in: Melanogenesis research · MC1R activation studies · Photoprotection models Half-life: ~1–2 hours ACTH(4-10) Analog · Stated purity ≥99% Semax Heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) derived from ACTH(4-10); studied for neurotrophin (BDNF/NGF) expression and melanocortin pathway interactions. Studied in: Neurotrophin signaling · Neuroprotection models · Cognitive-function paradigms Half-life: Short (minutes) in published models Melanocortin Agonist · Stated purity ≥99% PT-141 (Bremelanotide) Cyclic heptapeptide α-MSH analog acting at MC3R and MC4R; used to study central melanocortin signaling. Studied in: Melanocortin receptor pharmacology · Central signaling pathways · Receptor-subtype selectivity Half-life: ~2.7 hours Nonapeptide · Stated purity ≥99% Oxytocin Hypothalamic neuropeptide acting at the oxytocin receptor (Gq/11-coupled); used in neuroendocrine and receptor-signaling studies. Studied in: OXTR signaling · HPA-axis modulation models · Social-recognition paradigms Half-life: ~1–6 minutes (plasma)

In-depth research overviews

Detailed mechanism, pharmacokinetic, and research-area breakdowns for key compounds in our catalog. All content is for informational purposes — research use only.

MetabolicRetatrutideTriple GLP-1/GIP/Glucagon receptor agonistMetabolicTirzepatideDual GLP-1/GIP receptor agonistMetabolicCagrilintideLipidated amylin analogue; amylin receptor (calcitonin receptor/RAMP) backgroundMetabolic5-Amino-1MQSmall-molecule quinolinium studied as a nicotinamide N-methyltransferase (NNMT) inhibitorRecoveryBPC-157Pentadecapeptide studied for tissue repair and cytoprotectionRecoveryTB-500Thymosin Beta-4 fragment studied for systemic repair and angiogenesisGH PeptidesCJC-1295GHRH analog with DAC for sustained GH pulse stimulationGH PeptidesIpamorelinSelective GHS and ghrelin receptor agonistGH PeptidesTesamorelinGHRH(1-44) analog studied for GHRH receptor signalingGH PeptidesIGF-1 LR3Long R3 analog of IGF-1 studied for IGF-1 receptor signalingGH PeptidesCJC-1295 / Ipamorelin Blend (no DAC)Blend of two peptides acting on the GHRH receptor and the GHS receptor; receptor backgroundGH PeptidesSermorelinGHRH (1–29) amide; GHRH-receptor agonistLongevityMOTS-cMitochondria-derived peptide studied for AMPK activation and metabolic regulationLongevitySS-31 (Elamipretide)Mitochondria-targeting tetrapeptide studied for cardioprotection and oxidative stress reductionLongevityNAD+Coenzyme studied for redox metabolism, sirtuins and DNA-repair enzymesLongevityThymalinThymus-derived polypeptide complex studied in thymic peptide bioregulator and immune-cell culture researchCognitiveSelankTuftsin-derived heptapeptide studied for anxiolytic-like effects and BDNF modulationCognitiveSemaxACTH(4-10) analog studied in neuropeptide and neuroprotection modelsCognitiveDSIP (Delta Sleep-Inducing Peptide)Nonapeptide first isolated from rabbit cerebral venous blood; neuropeptide research backgroundResearch CompoundsMT-1 (Melanotan I / Afamelanotide)Synthetic α-MSH analog studied for MC1R activation and melanogenesisResearch CompoundsPT-141 (Bremelanotide)Cyclic melanocortin receptor agonist studied in receptor pharmacologyResearch CompoundsOxytocinHypothalamic nonapeptide studied for neuroendocrine signalingResearch CompoundsMT-2 (Melanotan II)Cyclic α-MSH analogue; melanocortin receptor pharmacology backgroundResearch CompoundsKisspeptin-10RF-amide neuropeptide fragment; KISS1R (GPR54) ligand backgroundResearch CompoundsHCG (Human Chorionic Gonadotropin)Glycoprotein hormone; receptor structure, glycosylation and analytical backgroundResearch CompoundsMethylcobalamin (Vitamin B12)Cobalamin cofactor; organometallic chemistry of the cobalt-carbon bondResearch CompoundsGHK-CuCopper-binding tripeptide; copper complexation and extracellular-matrix synthesis in cell modelsResearch CompoundsKPVC-terminal tripeptide of alpha-MSH; melanocortin-receptor and PepT1 uptake studies in cell and mouse modelsResearch CompoundsEpitalonSynthetic tetrapeptide Ala-Glu-Asp-Gly (AEDG)Research CompoundsThymosin Alpha-1N-acetylated 28-residue thymic peptide (Tα1)Research CompoundsGlutathioneTripeptide thiol γ-Glu-Cys-Gly (GSH)Research CompoundsARA-290 (Cibinetide)11-residue peptide from erythropoietin helix B

Laboratory science guides

Compound-neutral education on how peptides are made, analysed, stored and put into solution. These guides cite peer-reviewed literature and do not describe use of any material.

Laboratory scienceHow to Read an HPLC Chromatogram and a Purity ValueA chromatogram is a plot, and a purity value is one number taken from that plot. This guide explains what the plot shows, how the number is calculated, and what it does not tell you.Laboratory scienceMass Spectrometry for Peptide IdentityMass spectrometry weighs molecules. For a peptide, the question it answers is whether the measured mass matches the mass calculated from the expected sequence.Laboratory scienceLyophilization: Why Research Peptides Are Freeze-DriedMost research peptides are supplied as a dry cake rather than a solution. This guide explains what lyophilization does, why it helps, and what a dry cake does and does not tell you.Laboratory sciencePeptide Storage Stability and Degradation PathwaysPeptides change chemically and physically over time. Knowing the common routes helps you read an analytical result, keep useful records, and understand why storage conditions are written the way they are.Laboratory scienceCounter-Ions in Synthetic Peptides: TFA Salts and Acetate SaltsA synthetic peptide is almost never just the peptide. It is a salt, and the identity of the anion that comes with it changes the mass you weigh, the pH of a solution, and sometimes how an assay behaves.Laboratory scienceSolid-Phase Peptide Synthesis: An Overview of the ChemistryMost research peptides are made by building the chain one amino acid at a time on a solid support. Understanding the cycle explains where common impurities come from and why they show up in analytical data.Laboratory sciencePeptide Purity Versus Net Peptide ContentPurity is the share of the peptide-like material that is the right molecule; net peptide content is the share of the powder that is peptide at all. A powder can be 98 % pure and still be only about 75 % peptide by mass, so the two numbers are not interchangeable.Laboratory sciencePeptide Solubility and Aggregation: Laboratory BasicsGetting a peptide into solution is a chemistry question with a predictable shape. This guide covers the factors that decide solubility, how aggregation shows up, and how to keep records that make a result repeatable.Laboratory scienceReconstitution Math: How to Work Out Solution ConcentrationMaking a solution from a weighed or labelled amount of dry material comes down to a few lines of arithmetic. This guide sets out those lines, the assumptions hidden inside them, and the reasons a measured concentration can differ from the calculated one.Laboratory scienceBacteriostatic Water vs Sterile Water: A Laboratory Diluent ComparisonShort answer: bacteriostatic water is sterile water with a preservative, usually 0.9% benzyl alcohol, that inhibits bacterial growth after a container is opened; sterile water has no additive and is meant for single use. Both diluents are sterile water. One carries a preservative and one does not. This guide explains what that preservative is, what the word bacteriostatic actually promises, and why the choice of diluent is a variable worth recording.Laboratory scienceFreeze-Thaw Cycles and Aliquoting: Protecting Peptide Stock SolutionsShort answer: divide a peptide stock into single-use aliquots before its first freeze, so each portion is thawed once. Published data show a second freeze-thaw cycle can cost a large share of material, but the loss depends on the molecule, the buffer and the container. Freezing a solution is not a pause button. Ice formation, concentrated solutes and container surfaces all act on the material while it is frozen and while it thaws. This guide explains the mechanisms and what published stability studies show about repeated cycles.Laboratory scienceWhat Is Semax? Structure, Chemistry and the Published ResearchSemax is a synthetic heptapeptide built from a fragment of adrenocorticotropic hormone and a Pro-Gly-Pro tail. This primer sets out what it is chemically, what the cited laboratory literature describes, and what that literature cannot tell you.Laboratory scienceWhat Is Selank? Structure, Chemistry and the Published ResearchSelank is a synthetic heptapeptide derived from the natural tetrapeptide tuftsin. This primer covers its structure and chemistry, the in-vitro and rodent literature behind it, and the limits of what that literature shows.Laboratory scienceWhat Is NAD+? The Coenzyme, Its Chemistry and the Published ResearchNAD+ is not an enzyme, and it is not a peptide. It is a coenzyme: a small dinucleotide found in every living cell that enzymes use to carry electrons and consume as a cosubstrate. This primer explains what it is, the two roles the literature describes for it, how cells make and consume it, and what that means for the bench.Laboratory scienceWhat Is DSIP? The Delta Sleep-Inducing Peptide and Its Open QuestionsDSIP is a nine-residue peptide with a distinctive history. It was isolated in 1977, named for an effect seen in rabbits, and has stayed difficult to pin down since. This primer covers its chemistry and what the literature itself says is unresolved.Laboratory sciencePeptide Sequence Notation: How to Read a Written PeptideA written peptide sequence is a compact chemical description. Read correctly, it tells you the order of residues, how the two ends are capped, which residues are mirror-image forms and whether the chain is closed into a ring, and it is the starting point for every mass you calculate.Laboratory scienceEndotoxin in Peptide Research: What It Is and How It Is MeasuredEndotoxin is a component of bacterial cell walls that survives the steps most laboratories use to make a solution sterile. In very small amounts it can switch on immune cells in culture, so a result credited to a peptide can come from a contaminant instead. This guide explains what endotoxin is, how it is measured and how it is kept out of laboratory solutions.Laboratory scienceDisulfide Bonds and Free Thiols in Peptides: A Laboratory GuideCysteine is the one common amino acid whose side chain can link to another residue on its own, through a sulfur-sulfur bond. Whether a cysteine is a free thiol or part of a disulfide changes the mass, the shape and the behaviour of a peptide in solution. This guide explains how the two forms interconvert, how each is measured, and how laboratories keep the intended form intact.Laboratory sciencePeptide Adsorption to Labware: Why Dilute Solutions Lose PeptideA peptide solution can lose a large share of its peptide without any chemical change, simply because the molecules stick to the walls of the vial, tube or pipette tip. The loss is small for a concentrated stock and can be most of the material in a dilute working solution. This guide explains why, summarises what published recovery studies measured, and sets out how laboratories reduce the effect and check for it.Laboratory sciencePeptide Stability in Serum and Plasma: How In Vitro Assays WorkBlood contains enzymes that cut peptide bonds, so a peptide placed in serum or plasma is gradually broken into fragments. Serum and plasma stability assays measure how quickly that happens and where the chain is cut. This guide explains what the assay measures, why serum, plasma and whole blood give different answers, how the incubation, quenching and readout steps are run, how a half-life is calculated, and what a result can and cannot tell you.Laboratory scienceChoosing a Buffer and pH for Peptide SolutionsThe pH of a peptide solution changes its charge, its solubility and the rate of several degradation reactions, so the choice of buffer is part of the experiment rather than a detail. This guide covers where a buffer works, recipe arithmetic, buffer capacity, temperature and freezing shifts, buffer chemistry, mass spectrometry and record keeping.Laboratory scienceCircular Dichroism for Peptides: Reading Secondary StructureCircular dichroism (CD) spectroscopy is a quick way to see whether a peptide in solution is helical, sheet-like or largely disordered, and whether that changes with solvent, temperature or time. This guide covers what the spectrum measures, the shapes to recognise, unit conversion, sample preparation, structure estimation and what CD cannot tell you.Laboratory scienceReading Peptide Receptor Assays: Kd, Ki, IC50 and EC50Papers on receptor-active peptides report Kd, Ki, IC50 and EC50 values, often side by side, but they come from different experiments. This guide explains what each one measures, how they are related, worked conversions, and why one peptide can give different values in different laboratories.Laboratory scienceHow to Measure Peptide Concentration: UV Absorbance, Amino Acid Analysis and Dye AssaysThe concentration written on a tube is usually the weighed mass divided by the volume, which is not the same as the amount of peptide in solution. This guide compares the methods laboratories use to measure it, with worked examples for UV absorbance at 280 and 205 nm and for amino acid analysis, and explains why protein dye assays are a poor fit for short peptides.Laboratory scienceDMSO Stock Solutions: Preparing, Storing and Diluting Peptides for AssaysDimethyl sulfoxide (DMSO) dissolves many hydrophobic peptides and small molecules that water will not, which is why it is the standard solvent for assay stock solutions. It is also hygroscopic, freezes near room temperature, can oxidize thiols and affects proteins and cells at low percentages. This guide covers stock preparation, storage, dilution into assays and the controls that keep DMSO from becoming a hidden variable, with worked examples.Laboratory scienceSterile Filtration of Peptide Solutions: Membranes, Peptide Losses and IntegrityPassing a solution through a 0.2 or 0.22 µm membrane is the usual way to remove bacteria from a peptide solution before cell culture or other sensitive laboratory work. The membrane is not inert: it can bind peptide, release extractable compounds and, under some conditions, let very small organisms through, and it does not remove endotoxin. This guide covers membrane choice, how to measure and limit peptide loss, pre-flushing, integrity checks and what to record, with worked examples.Laboratory sciencePeptide Oxidation in the Lab: Methionine, Tryptophan and HistidineOxidation is one of the most common chemical changes in stored peptides. It mainly affects methionine, tryptophan, histidine, cysteine and tyrosine, and it is driven by peroxides, trace metal ions, light and oxygen rather than by time alone. This guide explains how each route works, how oxidized forms show up in mass spectra and chromatograms, how analysis itself can create oxidation, and which handling steps and additives limit it, with worked examples.Laboratory sciencePeptide Deamidation in the Lab: Asparagine, Glutamine and IsoaspartateDeamidation turns an asparagine or glutamine side chain into a carboxylic acid. It is one of the most common chemical changes of peptides in solution, and its speed depends on the neighbouring residue, pH and buffer. This guide covers the succinimide route, rates, worked arithmetic, mass spectra, isoaspartate analysis and aspartimide formation in synthesis.Laboratory sciencePyroglutamate Formation in Peptides: N-Terminal Gln, Glu and DetectionPyroglutamate (pGlu, also written Glp or 5-oxoproline) forms when an N-terminal glutamine or glutamic acid closes into a five-membered lactam. Glutamine does this quickly in solution; glutamic acid is much slower. This guide covers the chemistry, rates, worked mass and half-life arithmetic, detection by MS and RP-HPLC, the difference from side-chain deamidation, and a practical record checklist.

Also in the library: the Learn hub, the laboratory glossary (127 terms), the laboratory tools and 4 free printable lab sheets.

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Research use only. All information on this page is sourced from published peer-reviewed literature and is provided for educational and research purposes only. Nothing on this page constitutes medical advice, a treatment recommendation, or a claim of efficacy. All compounds sold by Sealed Peptides are strictly for in vitro and laboratory research use. Not for human or veterinary consumption.