--- title: "Guides for UK research peptide buyers | Sable Peptides" description: "Practical guides: UK supplier checklist, where to buy research peptides in the UK, how to read and verify a CoA, UK legal status and a lab concentration calculator. Research use only." canonical: https://www.sablepeptides.co.uk/guides publisher: Sable Peptides Limited (UK company 17488610) note: Research use only. Not for human or veterinary use. --- # Guides Practical, checkable guidance for labs buying research peptides in the UK. Research use only. - [UK research peptide supplier checklist](/guides/uk-research-peptide-supplier-checklist)A practical checklist for choosing a UK research peptide supplier: company records, lot-specific CoAs, lab verification, labelling, dispatch, payment and pricing. Research use only. - [Where to buy research peptides in the UK](/guides/where-to-buy-research-peptides-uk)Where UK labs buy research peptides: specialist UK suppliers, chemical distributors and custom synthesis, with what to check and how to compare prices fairly. Research use only. - [How to read a certificate of analysis (CoA)](/guides/how-to-read-a-coa)How to read a research peptide CoA line by line: lot number, lab and task number, HPLC purity, mass spectrometry identity, measured content and what each figure does and does not show. - [UK legal status of research peptides: the facts](/guides/uk-legal-status-of-research-peptides)Verified summary of the UK law that applies to research peptides: the Human Medicines Regulations 2012, the Misuse of Drugs Act 1971 and the Psychoactive Substances Act 2016, each with its source. Not legal advice. - [HPLC and mass spectrometry on a peptide CoA, explained](/guides/hplc-and-mass-spectrometry-on-a-peptide-coa)What the HPLC purity figure and the mass spectrometry identity result on a research peptide certificate of analysis actually measure, what they cannot show, and how to check them. Research use only. - [Peptide purity vs net peptide content](/guides/peptide-purity-vs-net-peptide-content)Why a research peptide can be 99% pure by HPLC yet contain less than its labelled weight as peptide: counter-ions such as TFA and acetate, residual water, and how net peptide content is measured. Research use only. - [Handling lyophilised peptides in the lab: receipt to storage](/guides/lyophilised-peptide-handling-for-labs)A laboratory handling routine for freeze-dried research peptide vials: checking a delivery, recording lot numbers, avoiding moisture uptake, aliquoting and storage. Complements our storage reference data. Research use only. - [UK research peptide prices: October 2026 report](/guides/uk-research-peptide-price-report-october-2026)A dated snapshot of UK research peptide prices from Sable's daily price check of 16 October 2026: 60 compounds, 30 UK suppliers checked, Sable vs the cheapest named UK seller at the same mg size. - [Lot numbers and traceability in research peptide supply](/guides/lot-numbers-and-traceability-in-research-supply)What a lot (batch) number is, how it links a vial to its synthesis, testing and certificate, and what traceability a lab should expect from a research peptide supplier. Research use only. - [Endotoxin testing for research peptides: LAL and recombinant factor C](/guides/endotoxin-testing-for-research-peptides)What bacterial endotoxin is, how the LAL and recombinant factor C (rFC) tests detect it, what an EU/mg result on a peptide certificate means, and the limits of each method. Research use only. - [Sterility vs endotoxin vs bioburden: three different tests](/guides/sterility-vs-endotoxin-vs-bioburden)Sterility, bioburden and endotoxin answer different questions about microbial contamination. What each test measures, how it is run, and why research-grade peptide CoAs rarely include all three. Research use only. - [Amino acid analysis: how peptide content is measured](/guides/amino-acid-analysis-for-peptide-content)How amino acid analysis (AAA) quantifies the actual peptide in a lyophilised powder: acid hydrolysis, derivatisation or LC-MS detection, sources of error, and how it relates to net peptide content on a CoA. Research use only. - [Measuring residual TFA in synthetic peptides: ion chromatography and 19F NMR](/guides/measuring-residual-tfa-in-peptides)How laboratories quantify residual trifluoroacetate (TFA) in a synthetic peptide: ion chromatography, 19F NMR and related methods, what the result is expressed as, and why it affects content calculations. Research use only. - [Water content on a peptide CoA: Karl Fischer titration explained](/guides/water-content-karl-fischer-on-peptide-coas)How residual water in a lyophilised peptide is measured by Karl Fischer titration, coulometric vs volumetric methods, sources of error, and why water content matters for stability and weighing. Research use only. - [Method validation terms on a CoA: specificity, LOD, LOQ, linearity (ICH Q2)](/guides/analytical-method-validation-terms-on-a-coa)Plain definitions of the analytical validation terms that appear on peptide certificates and lab reports, from ICH Q2(R2): specificity, accuracy, precision, linearity, range, LOD and LOQ, and what they tell you about a purity result. Research use only. - [Elemental impurities (ICH Q3D) and synthetic peptides](/guides/elemental-impurities-ich-q3d-and-peptides)What elemental impurities are, how ICH Q3D classifies them, how ICP-MS and ICP-OES measure them, and where metals can enter peptide synthesis and purification. Research use only. - [ISO/IEC 17025 accreditation: what it means for a peptide testing lab](/guides/iso-17025-accreditation-for-peptide-testing-labs)What ISO/IEC 17025 accreditation covers, how to check a lab's scope, why accreditation is method-specific, and how it differs from a lab simply being independent. Research use only. - [Oxidation-prone residues in peptide solutions: Met, Cys and Trp](/guides/oxidation-prone-residues-in-peptide-solutions)Which amino acids make a peptide susceptible to oxidation in laboratory solutions, what the products look like by mass spectrometry, and handling steps that limit oxidation in assays. No dosing; research use only. - [Peptide aggregation in assay solutions: causes and checks](/guides/peptide-aggregation-in-assay-solutions)Why some peptides aggregate or self-assemble in laboratory solutions, the conditions that drive it, and practical checks (visual, UV, light scattering, thioflavin T) before an assay. No dosing; research use only. - [Khavinson short peptides: Epitalon, Pinealon, Vilon and Cartalax compared](/guides/khavinson-short-peptides-sequences-and-structure)The di-, tri- and tetrapeptides known as 'bioregulators': sequences, molecular formulas and masses from PubChem, and the research background of the Khavinson group's work on short peptides and gene expression. Research use only. - [GHRP-2, GHRP-6, hexarelin and ipamorelin: structures compared](/guides/growth-hormone-releasing-peptides-ghrp-structures)The synthetic growth hormone-releasing peptides side by side: sequences with D-amino acids and non-natural residues, PubChem formulas and masses, and the research history that led to the discovery of ghrelin. Research use only. - [GHRH analogues: sermorelin, CJC-1295 and tesamorelin compared](/guides/ghrh-analogues-sermorelin-cjc-1295-tesamorelin)How sermorelin, modified GRF(1-29), CJC-1295 with DAC and tesamorelin relate to native growth hormone-releasing hormone: sequence changes, the DAC albumin-binding group, PubChem data and analytical detection. Research use only. - [α-MSH and its analogues: Melanotan I, Melanotan II, PT-141 and KPV](/guides/melanocortin-peptides-alpha-msh-analogues)How Melanotan I (afamelanotide), Melanotan II, PT-141 (bremelanotide) and the KPV tripeptide relate to α-melanocyte-stimulating hormone: sequences, cyclisation, PubChem data and research background. Research use only. - [Selank and Semax: tuftsin- and ACTH-derived heptapeptides](/guides/selank-and-semax-tuftsin-and-acth-analogues)Selank and Semax are both short peptides capped with Pro-Gly-Pro. Their sequences, parent peptides (tuftsin and ACTH 4-10), PubChem data and research background, side by side. Research use only. - [Mitochondria-associated peptides: SS-31 and MOTS-c compared](/guides/mitochondria-targeted-peptides-ss-31-and-mots-c)Two very different peptides studied in mitochondrial research: SS-31, a synthetic cardiolipin-binding tetrapeptide, and MOTS-c, a 16-residue peptide encoded in mitochondrial DNA. Sequences, PubChem data and research background. Research use only. - [UK GH secretagogue and GHRH analogue peptide prices: October 2026](/guides/uk-gh-secretagogue-peptide-prices-october-2026)UK prices for growth hormone secretagogue and GHRH analogue research peptides from the daily price check of 16 October 2026: Sable vs the lowest other UK listing and the median, same compound and same mg size. Research use only. - [UK bioregulator peptide prices: October 2026](/guides/uk-bioregulator-peptide-prices-october-2026)UK prices for bioregulator (short peptide) research peptides from the daily price check of 16 October 2026: Sable vs the lowest other UK listing and the median, same compound and same mg size. Epitalon, Pinealon, Thymalin, Vesugen, Vilon, Cartalax. Research use only. - [UK metabolic and mitochondrial research peptide prices: October 2026](/guides/uk-metabolic-research-peptide-prices-october-2026)UK prices for metabolic and mitochondrial research peptides from the daily price check of 16 October 2026: Sable vs the lowest other UK listing and the median, same compound and same mg size. Retatrutide, tirzepatide, cagrilintide, AOD 9604, MOTS-c, SS-31, NAD+, 5-Amino-1MQ, SLU-PP-332. Research use only. - [UK neuropeptide and melanocortin peptide prices: October 2026](/guides/uk-neuropeptide-and-melanocortin-prices-october-2026)UK prices for neuropeptide and melanocortin research peptides from the daily price check of 16 October 2026: Sable vs the lowest other UK listing and the median, same compound and same mg size. Selank, Semax, Adamax, DSIP, Dihexa, oxytocin, kisspeptin-10, PT-141, Melanotan I and II. Research use only. - [Tandem mass spectrometry for peptides: b and y ions explained](/guides/tandem-ms-b-and-y-ions-explained)How MS/MS fragments a peptide along its backbone, what b and y ions are, how a sequence is read from the ladder of fragment masses, and where the method can mislead. Research use only. - [Charge states and adducts in peptide mass spectra: reading the extra peaks](/guides/esi-charge-states-and-adducts-in-peptide-spectra)Why an electrospray mass spectrum of one peptide shows several peaks: multiple charge states, sodium and potassium adducts, TFA clusters and in-source fragments, and how deconvolution turns them into one mass. Research use only. - [Deamidation and isoaspartate in peptides: detection and prevention](/guides/deamidation-and-isoaspartate-in-peptides)How asparagine and glutamine residues deamidate through a succinimide intermediate, why Asn-Gly is the fastest site, how the +0.984 Da change is detected, and handling conditions that slow it. Research use only. - [Pyroglutamate and diketopiperazine: N-terminal cyclisation in peptides](/guides/pyroglutamate-and-diketopiperazine-formation)Two cyclisation reactions that change peptides at the N-terminus: glutamine or glutamate cyclising to pyroglutamate (−17 or −18 Da), and dipeptide loss as a diketopiperazine. Mechanisms, detection and sequences at risk. Research use only. - [Marfey's method: measuring D-amino acid content in a peptide](/guides/marfeys-method-chiral-amino-acid-analysis)How chiral purity of a synthetic peptide is actually measured: total hydrolysis, derivatisation with Marfey's reagent (FDAA), HPLC separation of diastereomers, and correcting for racemisation during hydrolysis. Research use only. - [Measuring peptide concentration by UV: A280 vs A205](/guides/uv-absorbance-for-peptide-concentration-a280-and-a205)How laboratories estimate peptide concentration in solution from UV absorbance: the A280 method for Trp/Tyr-containing peptides, the A205 method for peptides without them, extinction coefficients and the common errors. No dosing; research use only. - [Nitrogen and CHN analysis: an alternative route to peptide content](/guides/nitrogen-and-chn-analysis-for-peptide-content)How elemental (CHN) or nitrogen analysis estimates the peptide content of a lyophilised powder, how it compares with amino acid analysis and UV, and when counter-ions skew the result. Research use only. - [HPLC system suitability: resolution, tailing and plate count](/guides/hplc-system-suitability-explained)What system suitability tests check before an HPLC purity result is accepted: resolution, tailing factor, theoretical plates, repeatability and signal-to-noise, and what they mean for a peptide chromatogram. Research use only. - [Why peptides elute where they do: RP-HPLC retention and hydrophobicity](/guides/rp-hplc-retention-and-peptide-hydrophobicity)How a peptide's sequence determines its retention time on reversed-phase HPLC, hydrophobicity indexes and retention prediction, and why retention time alone is not an identity test. Research use only. - [Isoelectric point (pI) of peptides: calculation and lab use](/guides/isoelectric-point-of-peptides-explained)What a peptide's isoelectric point is, how it is calculated from pKa values, why different calculators disagree, and how pI guides solvent choice, buffer pH and purification in the lab. No dosing; research use only. - [Residual solvents in synthetic peptides: ICH Q3C classes and GC testing](/guides/residual-solvents-ich-q3c-and-peptides)Which organic solvents are used in peptide synthesis and purification, how ICH Q3C classifies them, how headspace GC measures traces, and what a residual-solvent line on a CoA means. Research use only. - [Forced degradation and stability-indicating methods for peptides](/guides/forced-degradation-and-stability-indicating-methods)What forced degradation (stress testing) is, the conditions used for peptides (acid, base, oxidation, heat, light), how it proves an HPLC method is stability-indicating, and how to read the results. Research use only. - [Stability study terms explained: ICH Q1A conditions, time points and shelf life](/guides/ich-q1a-stability-study-terms)A glossary-style guide to the vocabulary of stability studies from ICH Q1A(R2): long-term, intermediate and accelerated conditions, time points, significant change, retest period and shelf life, applied to lyophilised peptides. Research use only. - [Specification vocabulary from ICH Q6B: characterisation, purity, impurities and potency](/guides/ich-q6b-specification-terms-explained)A glossary deep dive into the terms ICH Q6B uses for biological products, product-related substances vs impurities, process-related impurities, contaminants, potency, and how they map onto a research peptide CoA. Research use only. - [Reporting, identification and qualification thresholds for impurities](/guides/related-substances-and-impurity-thresholds)What the three impurity thresholds in ICH Q3A mean, why synthetic peptides are outside its scope, how peptide-specific thresholds differ, and what 'largest single impurity' and 'total impurities' tell you on a CoA. Research use only. - [What happens when a peptide test result is out of specification?](/guides/out-of-specification-results-explained)How an out-of-specification (OOS) result is investigated: laboratory error checks, retesting rules, why averaging away a failure is not allowed, and what this means for trusting a CoA. Based on FDA OOS guidance. Research use only. - [How precise is a 99% purity result? Measurement uncertainty explained](/guides/measurement-uncertainty-in-peptide-purity-results)Why every analytical result, including HPLC purity, has a measurement uncertainty; how it is estimated (Eurachem/CITAC approach), how to read '99.2% ± 0.3%', and why two labs can report different figures for the same lot. Research use only. - [What is ALCOA+? Data integrity for CoAs and lab records](/guides/data-integrity-alcoa-for-lab-records)The ALCOA+ principles of data integrity (attributable, legible, contemporaneous, original, accurate, plus complete, consistent, enduring, available), as defined in MHRA guidance, and how they apply to certificates of analysis and lab notebooks. Research use only. - [What is the difference between a retest date and an expiry date?](/guides/retest-date-vs-expiry-date-on-a-coa)The difference between a retest date, an expiry date and a manufacture or test date on a peptide certificate, how ICH Q7 and Q1A define them, and what a buyer should record. Research use only. - [What are retention samples and why do they matter for lot traceability?](/guides/reserve-and-retention-samples-explained)What reference and retention (reserve) samples are, how EU GMP Annex 19 and ICH Q7 describe them, how long they are kept, and how they let a disputed lot be re-tested. Research use only. - [What is mean kinetic temperature? Temperature excursions in peptide storage and transit](/guides/mean-kinetic-temperature-and-temperature-excursions)How mean kinetic temperature (MKT) weights short warm periods more heavily than an arithmetic average, how to calculate it from logger data, and how to judge a temperature excursion during delivery or storage. Research use only. - [Container closure integrity: how a sealed vial keeps a peptide dry](/guides/container-closure-integrity-for-peptide-vials)What container closure integrity (CCI) means for crimped peptide vials, the main test methods (dye ingress, vacuum decay, helium leak, headspace analysis), and the visual checks a lab can make on receipt. Research use only. - [Are peptides light-sensitive? Photostability and ICH Q1B explained](/guides/photostability-ich-q1b-for-peptides)Which peptide residues are light-sensitive, what ICH Q1B photostability testing requires (1.2 million lux hours and 200 W·h/m² UV), and practical light protection for peptide stocks in the lab. Research use only. - [Do peptide vials need a desiccant? Humidity control in lab storage](/guides/desiccants-and-humidity-control-for-peptide-storage)How moisture reaches stored lyophilised peptides, when desiccants help, the difference between silica gel and molecular sieves, humidity indicator cards, and the condensation problem with cold vials. Research use only. - [What is the difference between area %, weight % and assay on a peptide CoA?](/guides/area-percent-vs-weight-percent-vs-assay)A glossary deep dive into three numbers that are often confused: HPLC area percent (purity), weight percent (content), and assay against a reference standard. What each measures, how they relate, and which to use for concentration. Research use only. - [What is peptide mapping? Enzymatic digestion and LC-MS for longer peptides](/guides/peptide-mapping-by-enzymatic-digestion)How peptide mapping confirms the sequence of longer peptides and small proteins: enzymatic digestion (trypsin, Glu-C), LC-MS of the fragments, sequence coverage and what a map can and cannot show. Research use only. - [Can NMR check a peptide's identity and purity? qNMR explained](/guides/nmr-for-peptide-identity-and-qnmr-purity)How 1H NMR complements HPLC and MS for synthetic peptides: structural identity, detecting undeclared constituents, and quantitative NMR (qNMR) purity against an internal standard. Research use only. - [How is peptide aggregation measured? Size-exclusion chromatography explained](/guides/size-exclusion-chromatography-for-peptide-aggregates)How size-exclusion chromatography (SEC) separates monomer from dimers and higher aggregates, the role of MALS detection, artefacts from column interactions, and when SEC is relevant to peptides. Research use only. - [What does circular dichroism tell you about a peptide?](/guides/circular-dichroism-for-peptide-secondary-structure)How circular dichroism (CD) spectroscopy estimates α-helix, β-sheet and disordered content of peptides in solution, the characteristic far-UV signatures, analysis software, and practical sample limits. Research use only. - [TFA or formic acid? Mobile-phase additives in peptide LC-MS](/guides/tfa-vs-formic-acid-in-lc-ms-of-peptides)Why trifluoroacetic acid gives sharp HPLC peaks but suppresses electrospray MS signal, why formic acid is the usual LC-MS choice, and where difluoroacetic acid fits. What this means for comparing CoA chromatograms. Research use only. - [What are ghost peaks? Carryover and blank injections in peptide HPLC](/guides/hplc-carryover-ghost-peaks-and-blanks)How carryover from a previous injection, mobile-phase contaminants and gradient artefacts create ghost peaks in peptide chromatograms, why blank injections matter, and how to tell an artefact from a real impurity. Research use only. - [How are HPLC peaks integrated, and how can integration change purity?](/guides/chromatographic-peak-integration-rules)How chromatography software integrates peaks (baseline drop, valley, tangent skim), why manual reintegration is controlled, and how integration choices move a purity result by tenths of a percent. Research use only. - [What is a relative response factor, and why does it matter for purity?](/guides/relative-response-factors-for-peptide-impurities)Why HPLC area percent assumes every impurity absorbs UV like the main peptide, how relative response factors (RRFs) correct for it, how they are determined, and when the error is large for peptides. Research use only. - [What does 'mass accuracy 2 ppm' mean? High-resolution MS for peptide identity](/guides/high-resolution-ms-mass-accuracy-and-isotope-patterns)How high-resolution mass spectrometry confirms a peptide's elemental formula: ppm mass error, resolving power, isotope patterns and the monoisotopic peak, and how to read an observed-vs-theoretical mass line on a CoA. Research use only. - [What is the difference between GLP, GMP and ISO/IEC 17025?](/guides/glp-vs-gmp-vs-iso-17025-quality-systems)Three quality frameworks that are often confused: GLP for non-clinical safety studies, GMP for manufacturing medicines and APIs, and ISO/IEC 17025 for testing-lab competence. What each covers, who inspects it in the UK, and which applies to a research peptide CoA. Research use only. - [CoA vs CoC: what must a certificate of analysis contain under ICH Q7?](/guides/coa-vs-coc-what-ich-q7-requires-on-a-certificate)A certificate of analysis reports measured test results for one lot; a certificate of conformance only states that a product meets a specification. How to tell them apart, what ICH Q7 expects on a CoA, and why it matters for research peptides. Research use only. - [How do you send a peptide sample for independent testing?](/guides/sending-a-peptide-sample-for-independent-testing)A practical guide to commissioning an independent HPLC/MS test of a research peptide: choosing an accredited lab, chain-of-custody records, sample amount, packing, and reading the report against the supplier's CoA. Research use only. - [What should a research peptide vial label show?](/guides/what-a-research-peptide-vial-label-should-show)The information a research peptide vial label should carry: compound name, stated amount, printed lot number, storage condition and research-use statement, how it links to the CoA, and how ICH Q7 approaches labelling and traceability. Research use only. - [What is lot genealogy? Batch records and traceability explained](/guides/batch-records-and-lot-genealogy)How batch records and lot genealogy trace a finished peptide lot back through purification, synthesis and raw-material lots, and forward to every vial sold, with ICH Q7 definitions and what a research buyer can reasonably ask. Research use only. - [How to verify a peptide CoA and spot signs of alteration](/guides/how-to-check-a-peptide-coa-for-alteration)Practical document checks for a research peptide certificate: lot-number match, lab identity and verification, internal consistency of masses and dates, chromatogram plausibility, and when to request confirmation from the issuing lab. Research use only. - [Should peptides be stored at −20 °C or −80 °C?](/guides/minus-20-vs-minus-80-freezers-for-peptide-storage)How −20 °C and −80 °C storage compare for lyophilised peptides and peptide solutions, why frost-free freezers cycle temperature, door and alarm practice, and how to choose for a research lab. Research use only. - [Do lyophilised peptides need cold shipping? Ambient, cold packs and dry ice compared](/guides/shipping-peptides-cold-packs-and-dry-ice)When lyophilised peptides can travel at ambient temperature, when cold packs or dry ice are used, dry ice as a dangerous good (UN 1845), and what to check on arrival. Research use only. - [How should peptide stock solutions be aliquoted and recorded?](/guides/aliquoting-peptide-stock-solutions)Why and how to divide a peptide stock solution into single-use aliquots: choosing volumes, tubes, labelling, freezing, records linking each aliquot to the vial's lot number, and when to discard. No dosing; research use only. - [Why does freezing change the pH of a peptide solution?](/guides/freeze-thaw-and-ph-shift-in-frozen-peptide-solutions)How buffer components crystallise during freezing and shift pH (notably sodium phosphate), how freeze-concentration drives aggregation and degradation, and which buffers and practices reduce freeze–thaw damage. Research use only. - [Which syringe filter should be used for a peptide solution?](/guides/filtering-peptide-solutions-membrane-choice)How membrane material (PES, PVDF, nylon, cellulose acetate) affects peptide loss by adsorption during filtration, pore sizes, pre-rinsing and how to check recovery. No dosing; research use only. - [Which buffer should a peptide assay solution use?](/guides/buffer-choice-for-peptide-assay-solutions)How to choose a buffer for peptide research solutions: pKa and buffering range, temperature and freezing behaviour, metal and phosphate interactions, compatibility with LC-MS, and a comparison table of common buffers. Research use only. - [When is DMSO used to dissolve peptides, and what are the risks?](/guides/dmso-stock-solutions-for-peptides)Why DMSO is used for hydrophobic peptides and compound libraries, its hygroscopicity and freezing point (18.5 °C), oxidation risk for cysteine and methionine, water uptake and freeze–thaw effects on stored stocks. Research use only. - [What is the difference between hygroscopic and deliquescent?](/guides/hygroscopic-vs-deliquescent-glossary)Definitions of hygroscopic, deliquescent, efflorescent and critical relative humidity, why lyophilised peptides are hygroscopic, how moisture uptake affects weighing and stability, and practical handling. Research use only. - [Why does a peptide's molecular weight differ between the salt and free base?](/guides/salt-form-vs-free-base-molecular-weight)How counter-ions such as acetate, TFA and hydrochloride add to a peptide's formula weight, how to convert between salt and free-base mass, and why CoAs, PubChem and mass spectra can show different numbers. Research use only. - [What are lyoprotectants and bulking agents in freeze-dried peptides?](/guides/lyoprotectants-and-bulking-agents-glossary)Definitions of lyoprotectant, cryoprotectant, bulking agent, cake collapse, glass transition (Tg′) and residual moisture, with common excipients such as trehalose, sucrose and mannitol, and why many research peptides are supplied without excipients. Research use only. - [BPC-157: sequence, structure and published research background](/guides/bpc-157-sequence-structure-and-research-background)What BPC-157 is chemically: a 15-residue synthetic peptide (GEPPPGKPADDAGLV), its PubChem data, where the published research comes from and what it does and does not establish. Research use only. - [Thymosin alpha-1 vs thymosin beta-4 (TB-500): what is the difference?](/guides/thymosin-alpha-1-vs-thymosin-beta-4-and-tb-500)Thymosin alpha-1 and thymosin beta-4 share a name but are unrelated peptides. Their sequences, origins and PubChem data compared, and where TB-500 (Ac-LKKTETQ) fits in. Research use only. - [GHK-Cu vs Pal-GHK: what is the difference between the copper peptide and the palmitoyl tripeptide?](/guides/ghk-cu-vs-pal-ghk-copper-peptide-and-lipopeptide)GHK-Cu and Pal-GHK share the Gly-His-Lys sequence but are different materials: one is a copper(II) complex, the other a palmitoylated lipopeptide with no copper. Chemistry, PubChem data and literature compared. - [Matrixyl vs SNAP-8: what is the difference between these cosmetic research peptides?](/guides/matrixyl-vs-snap-8-signal-and-neurotransmitter-peptides)Matrixyl (palmitoyl pentapeptide-4, Pal-KTTKS) and SNAP-8 (acetyl octapeptide-3) come from different protein sources and are designed on different principles. Sequences, PubChem data and origin papers compared. - [Kisspeptin-10, gonadorelin and triptorelin: how do these reproductive-axis peptides differ?](/guides/kisspeptin-10-gonadorelin-and-triptorelin-compared)Kisspeptin-10 acts upstream of GnRH neurons; gonadorelin is GnRH itself; triptorelin is a D-Trp6 GnRH analogue. Sequences, receptors, PubChem data and key papers compared. Research use only. - [Oxytocin: structure, disulfide ring and research background](/guides/oxytocin-structure-disulfide-ring-and-research-background)Oxytocin is a cyclic nonapeptide with a Cys1–Cys6 disulfide and an amidated C-terminus. Its structure compared with vasopressin, PubChem data, the 2020 receptor crystal structure, and what this means for lab handling. - [LL-37: the human cathelicidin peptide's structure and research](/guides/ll-37-human-cathelicidin-structure-and-research)LL-37 is the only human cathelicidin: a 37-residue cationic amphipathic peptide cut from hCAP18. Sequence, charge, NMR structures, minimal fragments and PubChem data. Research use only. - [ARA-290 (cibinetide): the erythropoietin helix-B peptide explained](/guides/ara-290-epo-derived-helix-b-peptide)ARA-290 is an 11-residue peptide modelled on helix B of erythropoietin, designed to engage the tissue-protective receptor without the erythropoietic receptor. Sequence, PubChem data and research background. - [Dihexa and P21: what are these peptidomimetics?](/guides/dihexa-and-p21-peptidomimetics-explained)Dihexa (an angiotensin IV-derived hexanoyl dipeptide amide) and P21 (an adamantyl-glycine capped peptide) are peptidomimetics, not ordinary peptides. Structures, PubChem data and research background compared. - [Semaglutide vs tirzepatide vs retatrutide: what is the structural difference?](/guides/semaglutide-vs-tirzepatide-vs-retatrutide-structures)Semaglutide targets GLP-1R, tirzepatide GIPR and GLP-1R, and retatrutide GIPR, GLP-1R and glucagon receptor. Backbones, lipidation, receptor profiles and structural papers compared. Research use only; no clinical claims. - [Cagrilintide: what is a long-acting amylin analogue?](/guides/cagrilintide-long-acting-amylin-analogue-explained)Cagrilintide is a lipidated analogue of the 37-residue pancreatic hormone amylin, designed for stability and long action, with activity at amylin and calcitonin receptors. Structure, PubChem data and literature. - [IGF-1 LR3 vs MGF vs PEG-MGF: what is the difference?](/guides/igf-1-lr3-vs-mgf-vs-peg-mgf)IGF-1 LR3 is an 83-residue recombinant IGF-I analogue with reduced binding-protein affinity; MGF is a synthetic peptide from the IGF-I Ec E-domain; PEG-MGF is its PEGylated form. Origins, structure and literature compared. - [FOXO4-DRI: what is a D-retro-inverso peptide?](/guides/foxo4-dri-and-d-retro-inverso-peptide-design)FOXO4-DRI is a D-retro-inverso peptide based on FOXO4 and published in 2017 in a study of senescent cells. How retro-inverso design works, PubChem data, and what it means for analysis. Research use only. - [DSIP (delta sleep-inducing peptide): structure and history](/guides/dsip-delta-sleep-inducing-peptide-structure-and-history)DSIP is the nonapeptide Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu, first reported in 1977 from rabbit blood. Its sequence, PubChem data, the unresolved question of its gene, and review literature. Research use only. - [NAD+, 5-Amino-1MQ and SLU-PP-332: why are non-peptides in a peptide catalogue?](/guides/non-peptide-compounds-nad-5-amino-1mq-slu-pp-332)Three research compounds in the Sable catalogue are not peptides: NAD+ (a dinucleotide coenzyme), 5-Amino-1MQ (a quinolinium NNMT inhibitor) and SLU-PP-332 (an ERR agonist). Chemistry, PubChem data and research background. - [UK BPC-157 and TB-500 prices: October 2026](/guides/uk-bpc-157-and-tb-500-prices-october-2026)UK BPC-157 and TB-500 prices from the daily price check of 16 October 2026: Sable vs the lowest, median and highest other UK listings, same compound and same mg size. BPC-157, TB-500. Research use only. - [UK GHK-Cu, Pal-GHK and SNAP-8 prices: October 2026](/guides/uk-copper-and-cosmetic-peptide-prices-october-2026)UK copper and cosmetic peptide prices from the daily price check of 16 October 2026: Sable vs the lowest, median and highest other UK listings, same compound and same mg size. GHK-Cu, Pal-GHK, SNAP-8. Research use only. - [UK thymosin alpha-1, LL-37, KPV and ARA-290 prices: October 2026](/guides/uk-immune-and-antimicrobial-peptide-prices-october-2026)UK immune-related and antimicrobial peptide prices from the daily price check of 16 October 2026: Sable vs the lowest, median and highest other UK listings, same compound and same mg size. Thymosin alpha-1, LL-37, KPV, ARA-290. Research use only. - [UK IGF-1 LR3, MGF, PEG-MGF, follistatin and FOXO4-DRI prices: October 2026](/guides/uk-growth-factor-and-protein-research-material-prices-october-2026)UK growth-factor, protein and large-peptide prices from the daily price check of 16 October 2026: Sable vs the lowest, median and highest other UK listings, same compound and same mg size. IGF-1 LR3, MGF, PEG-MGF, Follistatin 344, FOXO4-DRI. Research use only. - [Are bigger peptide vials cheaper per mg? UK vial-size analysis, October 2026](/guides/uk-peptide-price-per-mg-by-vial-size-october-2026)How price per mg falls with vial size across 29 compounds sold in more than one size, from the UK daily price check of 16 October 2026, including the cases where a larger vial cost less in total. - [Buying retatrutide, tirzepatide or cagrilintide for research: what should you check?](/guides/buyer-checklist-for-lipidated-incretin-research-peptides)A buyer checklist for large lipidated research peptides (retatrutide, tirzepatide, semaglutide, cagrilintide): the identity, mass, labelling and pricing points that differ from short peptides. Research use only. - [How do you compare UK research peptide prices like for like?](/guides/how-to-compare-uk-peptide-prices-like-for-like)A method for comparing research peptide prices across UK sellers: same compound, same mg, in-stock, VAT, postage and per-mg arithmetic, with worked examples from the latest daily check. - [How much does postage add to a small research peptide order in the UK?](/guides/small-order-postage-and-the-real-cost-of-a-research-vial)Worked examples of how postage changes the real cost of a single research vial in the UK, where the free-delivery threshold sits, and how to plan an order around it. Uses Sable's published delivery terms. - [How does Pay by Bank work for a UK research peptide order?](/guides/pay-by-bank-for-research-peptide-orders-explained)What Pay by Bank (open banking payment) is, how a Sable order is paid via Wallid, what the buyer sees in their banking app, and what to check before authorising any payment. - [What should you check before buying a named peptide blend?](/guides/buyer-checklist-for-named-peptide-blends)Named blends such as GLOW, KLOW, Wolverine and GH stack combine several peptides in one vial. A checklist for confirming composition, per-component mass, testing and price per component. Research use only. - [Epitalon vs N-acetyl Epitalon vs Epitalon sodium: what is the difference?](/guides/epitalon-vs-n-acetyl-epitalon-vs-epitalon-sodium)Three catalogue forms built on the tetrapeptide Ala-Glu-Asp-Gly (AEDG): free Epitalon, N-terminally acetylated Epitalon, and a sodium salt form. Formulas, PubChem data and what changes chemically. Research use only. - [AOD 9604 and hGH fragment 176-191: what is the relationship?](/guides/aod-9604-and-the-hgh-176-191-fragment)AOD 9604 is a 16-residue peptide based on the C-terminal region (176-191) of human growth hormone with an added N-terminal tyrosine. Structure, disulfide, PubChem data and published research history. Research use only. - [Follistatin 344: what is it and how does it differ from FS288 and FS315?](/guides/follistatin-344-recombinant-glycoprotein-explained)Follistatin 344 names the precursor that gives rise to the FS315 isoform of follistatin, an activin- and myostatin-binding glycoprotein. Isoforms, heparin binding and what a recombinant protein needs on a CoA. Research use only. - [Thymalin vs Vesugen: what is the difference between a peptide extract and a defined tripeptide?](/guides/thymalin-and-vesugen-extract-vs-defined-peptide)Thymalin is a thymus-derived peptide complex; Vesugen is the defined synthetic tripeptide Lys-Glu-Asp. Why one has a single structure and the other does not, and what that means for identity testing. Research use only. - [Which catalogue peptides are cyclic, and how are their rings formed?](/guides/cyclic-peptides-in-the-catalogue-disulfide-and-lactam-rings)A cross-catalogue look at cyclic research peptides: disulfide-bridged (oxytocin, AOD 9604, cagrilintide) and lactam-bridged (Melanotan II, PT-141). Ring types, sizes, PubChem data and why cyclisation matters for identity. - [Which research peptides contain D-amino acids, and why?](/guides/d-amino-acids-in-catalogue-peptides)A cross-catalogue table of research peptides that contain D-amino acids (GHRP-2, GHRP-6, hexarelin, ipamorelin, triptorelin, SS-31, Melanotan II, PT-141, CJC-1295, FOXO4-DRI), where they sit and why designers use them. - [Why are so many research peptides acetylated or amidated?](/guides/n-terminal-acetylation-and-c-terminal-amidation-across-the-catalogue)N-terminal acetylation and C-terminal amidation across the Sable catalogue: which peptides carry them, what each modification removes, the mass change, and how it relates to the native hormone. - [Lipidated vs PEGylated peptides: what is the difference?](/guides/lipidated-and-pegylated-peptides-in-the-catalogue)Fatty-acid (lipidated) and polyethylene glycol (PEGylated) modifications across the catalogue: palmitoyl cosmetic peptides, fatty-diacid incretin analogues, and PEG-MGF. Purpose, mass effect and analytical consequences. - [What are Aib, Nle, 2-Nal and Dmt in research peptide sequences?](/guides/non-standard-amino-acids-aib-nle-2nal-dmt)Non-coded amino acids that appear in catalogue sequences: α-aminoisobutyric acid (Aib), norleucine (Nle), 2-naphthylalanine (2-Nal), 2',6'-dimethyltyrosine (Dmt) and others, what each replaces and why. - [How big are research peptides? Molecular weights across the catalogue compared](/guides/research-peptide-molecular-weights-compared)Every catalogue compound with a published molecular weight, ranked from smallest to largest: from a 159.21 g/mol small molecule to a ~9 kDa recombinant protein, with what size means for identity testing and weighing. - [Is PT-141 the same as bremelanotide? Research peptide names, codes and synonyms](/guides/research-peptide-names-codes-and-synonyms)A cross-reference of research peptide names, non-proprietary names, development codes and cosmetic INCI names (PT-141, ARA-290, Matrixyl, SNAP-8, GHRP-2, retatrutide and more), each tied to a primary source. - [How do you use PubChem to check a research peptide?](/guides/pubchem-records-for-research-peptides-how-to-use-them)How a buyer or lab can use a PubChem compound record (CID, formula, molecular weight, synonyms) to check a research peptide listing, where PubChem falls short for peptides, and worked examples from the catalogue. - [Buying IGF-1 LR3 or follistatin for research: what should you check?](/guides/buyer-checklist-for-recombinant-protein-research-materials)Recombinant proteins such as IGF-1 LR3 and follistatin 344 need different checks from synthetic peptides: expression system, SDS-PAGE purity, intact mass, quantity basis and activity data. A buyer checklist. Research use only. - [Buying GHK-Cu, Matrixyl or SNAP-8 for research: what should you check?](/guides/buyer-checklist-for-cosmetic-peptide-research-materials)A checklist for cosmetic-science research peptides (GHK-Cu, Pal-GHK, Matrixyl, SNAP-8): INCI vs chemical names, copper content, lipopeptide identity, mass per vial and like-for-like pricing. Research use only. - [What should you ask a UK research peptide supplier before ordering?](/guides/questions-to-ask-a-uk-peptide-supplier-before-ordering)Twelve questions to put to a UK research peptide supplier before a first order (company, testing, lot traceability, pricing evidence, payment, delivery), with the answers Sable gives for each. - [What should a research peptide product page show?](/guides/what-to-check-on-a-research-peptide-product-page)The information a good online research peptide listing should give before you buy (compound identity, mg per vial, price per mg, stock, testing, lot traceability, delivery and research-use terms), with a scoring checklist. - [How much does research peptide delivery cost to the Scottish Highlands and islands?](/guides/research-peptide-delivery-to-the-highlands-and-islands)Delivery costs for research peptide orders to the Scottish Highlands and islands compared with mainland UK, the £50 free-delivery threshold, and worked order examples from the latest price check. - [How do you check a UK peptide supplier on Companies House?](/guides/how-to-check-a-uk-peptide-supplier-on-companies-house)How to use the free Companies House register to check a UK research peptide supplier's legal identity, incorporation date, registered office and filings, and how trading history and incorporation date can differ. - [UK peptide blend and stack prices: October 2026](/guides/uk-named-peptide-blend-prices-october-2026)UK named blend and stack prices from the daily price check of 16 October 2026: Sable vs the lowest, median and highest other UK listings, same compound and same mg size. GLOW stack, KLOW blend, Wolverine stack. Research use only. - [Which research peptides do most UK suppliers stock? Coverage analysis, October 2026](/guides/uk-peptide-supplier-coverage-by-compound-october-2026)How many UK suppliers listed each compound and size in stock at the 16 October 2026 daily price check: most and least widely stocked research peptides, and what thin coverage means for price comparisons. - [How much cheaper is the lowest UK peptide price than the next? Gap analysis, October 2026](/guides/uk-peptide-price-gap-to-next-cheapest-october-2026)For every compound and size matched at the 16 October 2026 daily UK price check, the gap between Sable's price and the next-cheapest UK listing: where it was pennies and where it was pounds. - [What does a typical research peptide basket cost in the UK? October 2026](/guides/uk-research-peptide-basket-cost-october-2026)A fixed basket of ten widely stocked research peptide vials priced at the 16 October 2026 daily UK check: Sable total vs the sum of next-lowest, median and highest UK listings, with delivery. - [How much do UK peptide prices vary between sellers? Spread analysis, October 2026](/guides/uk-peptide-price-spread-between-sellers-october-2026)The range between the cheapest and dearest UK listing for the same research peptide and size at the 16 October 2026 daily price check, for every pair with three or more other sellers. - [What is the cheapest research peptide per mg in the UK? League table, October 2026](/guides/uk-research-peptide-price-per-mg-league-table-october-2026)Every compound in the 16 October 2026 daily UK price check ranked by Sable's lowest price per mg at its best-value size, with the median other-seller per-mg price for comparison. - [Which research peptides are hardest to find in the UK? Thinly stocked compounds, October 2026](/guides/uk-hard-to-find-research-peptides-prices-october-2026)Research peptide compound-and-size pairs listed in stock by only one or two other UK suppliers at the 16 October 2026 daily price check: prices, the comparisons behind them, and how to judge a thin market. - [How to verify a CoA](/learn/how-to-verify-a-coa)Confirm a certificate with the testing lab using its task number and verification key. - [Reconstitution concentration calculator](/guides/reconstitution-concentration-calculator)Peptide mass and solvent volume to concentration in mg/mL. - [CoA library](/coa/library)Published lab certificates by lot.