Winhycare Pharma · Peptide research guides
Peptide Research Library
The Peptide Research Library is Winhycare Pharma’s set of technical guides on peptides: what a peptide API is, how peptides are made, how lyophilization (lyophilisation in UK spelling) and storage affect a peptide, how quality is tested, and the EU and US regulatory routes. Each guide names its author and reviewer and cites its sources.
Guides on research peptides are for laboratory research only. We do not give dosing or usage advice.
56 guides · Updated
Molecule guides
Structure, identity and research context for individual peptides, and how related molecules compare.
-
Amycretin: what it is, how it works and what studies have found
Amycretin, now named zenagamtide, is a 68-amino-acid single peptide that activates GLP-1 receptors and amylin and calcitonin receptors. It has been tested as a weekly subcutaneous and a daily oral form in phase 1 and phase 2 trials, and entered phase 3 (AMAZE and AMBITION) in 2026. It is not approved anywhere.
11 min read · Updated
-
Amylin analogues explained: amylin receptors and the peptides that target them
Amylin analogues are engineered versions of amylin, a 37-amino-acid hormone co-secreted with insulin. They act on amylin receptors (AMY1, AMY2, AMY3), each a calcitonin receptor paired with a RAMP protein. Pramlintide is the only approved one; long-acting analogues such as cagrilintide, petrelintide, eloralintide and amycretin are in clinical trials.
13 min read · Updated
-
AOD-9604: what it is, how it works and what studies have found
AOD-9604 is a synthetic 16-amino-acid peptide made of residues 177-191 of human growth hormone with an extra tyrosine at the N-terminus, closed by one disulfide bond. It was developed as an anti-obesity drug after rodent studies showed fat-metabolism effects without growth hormone's effects on glucose or IGF-1, but a larger phase 2b obesity trial was reported as unsuccessful in 2007 and it was never approved.
12 min read · Updated
-
BPC-157 vs TB-500: how the two peptides differ in structure, evidence and regulatory status
BPC-157 is a 15-residue fragment of a gastric juice protein (about 1419 g/mol); TB-500 is usually the acetylated 7-residue fragment Ac-LKKTETQ of thymosin beta-4 (889 g/mol). Both rest almost entirely on cell and animal studies, neither is approved anywhere, FDA's 2026 evaluations weighed against compounding both, and WADA bans both.
14 min read · Updated
-
BPC-157: what it is, how it is thought to work and what studies have found
BPC-157 is a synthetic 15-amino-acid peptide (GEPPPGKPADDAGLV, about 1419 g/mol) taken from a protein found in gastric juice. Almost all of its evidence comes from rat and cell studies, most of them from one Zagreb group. Human data are three small uncontrolled reports. It is not approved anywhere, and both FDA and WADA restrict it.
16 min read · Updated
-
Cagrilintide: what it is, how it works and what studies have found
Cagrilintide is an investigational long-acting analogue of the pancreatic hormone amylin. It is a 37-amino-acid peptide with a Cys2–Cys7 disulfide bridge, three substitutions versus pramlintide and a C20 fatty di-acid on its N-terminus, and it activates both amylin and calcitonin receptors. Its half-life is 159–195 hours.
12 min read · Updated
-
CJC-1295: what it is, how it works and what studies have found
CJC-1295 is a synthetic analogue of GHRH(1-29) with four amino-acid substitutions. The original molecule adds a lysine carrying a maleimidopropionyl 'Drug Affinity Complex' (DAC) that binds serum albumin, giving a 5.8–8.1 day half-life in healthy adults. The version without DAC, also called modified GRF(1-29), lacks that albumin-binding group. Neither is approved.
12 min read · Updated
-
Eloralintide: what it is, how it works and what studies have found
Eloralintide (LY3841136) is an investigational 37-amino-acid acylated amylin analogue that preferentially activates the amylin-1 receptor (AMY1R) over the calcitonin receptor. Peer-reviewed phase 1 and 48-week phase 2 data have been published, and the ENLIGHTEN phase 3 programme began in late 2025. It is not approved anywhere.
11 min read · Updated
-
FDA-approved peptide drugs: a list by INN, approval year, target and length
Reviews published in 2021 and 2022 put the number of peptide drugs approved worldwide at more than 80. The tables below list 55 FDA-approved peptides by INN, from oxytocin and glucagon to the 2026 approvals rusfertide, icotrokinra, enlicitide and navepegritide, with first Drugs@FDA approval year, target and length. Data cut-off: 26 October 2026.
13 min read · Updated
-
GLP-1 receptor agonists explained: how they work, the full list, and where research is heading
GLP-1 receptor agonists are peptides, and now one small molecule, that activate the receptor for the gut hormone glucagon-like peptide-1. The receptor raises cAMP in beta cells, increasing insulin secretion only when glucose is high, while also suppressing glucagon, slowing gastric emptying and reducing food intake. Dual and triple agonists add GIP or glucagon receptor activity.
14 min read · Updated
-
Linaclotide: what it is, how it works and what studies have found
Linaclotide is a 14-amino-acid peptide (CCEYCCNPACTGCY) held together by three disulfide bonds, Cys1-Cys6, Cys2-Cys10 and Cys5-Cys13. It activates guanylate cyclase-C on the intestinal lining, raising cGMP, and is minimally absorbed. FDA approved it in August 2012 for IBS with constipation and chronic idiopathic constipation; the EU authorised it for IBS-C in adults only.
12 min read · Updated
-
Mazdutide: what it is, how it works and what studies have found
Mazdutide (IBI362, LY3305677) is a 34-amino-acid acylated oxyntomodulin analogue that activates both the GLP-1 receptor and the glucagon receptor. China's NMPA approved it for chronic weight management in June 2025 and for glycaemic control in type 2 diabetes in September 2025. Elsewhere it remains investigational.
13 min read · Updated
-
Retatrutide vs tirzepatide: how the triple and dual agonists compare
Retatrutide is an investigational 39-residue peptide that activates GIP, GLP-1 and glucagon receptors; tirzepatide is an approved 39-residue GIP and GLP-1 receptor agonist. They share 30 of 39 positions and a C20 di-acid, but differ in linker, acylation site and receptor profile. No head-to-head result has been published; TRIUMPH-5 is ongoing.
12 min read · Updated
-
Retatrutide: what it is, how it works and what studies have found
Retatrutide (LY3437943) is an investigational 39-amino-acid peptide that activates the GIP, GLP-1 and glucagon receptors. It carries Aib at positions 2 and 20, α-methyl-leucine at 13 and a C20 fatty di-acid on lysine 17, giving a half-life of about 6 days. Phase 3 TRIUMPH results were published in 2026; it is not approved anywhere.
12 min read · Updated
-
Semaglutide vs tirzepatide vs liraglutide: how the three peptide APIs compare
How semaglutide, tirzepatide and liraglutide APIs differ: backbone, length, lipid chain, receptors, half-life basis, molecular weight, CAS and approval.
9 min read · Updated
-
Semaglutide: what it is, how it works and what studies have found
Semaglutide is a 31-amino-acid analogue of human GLP-1(7–37) that activates the GLP-1 receptor. An Aib substitution at position 8 blocks DPP-4 cleavage, and a C18 fatty di-acid on lysine 26 binds albumin, giving an elimination half-life of about one week. Phase 3 programmes (SUSTAIN, PIONEER, STEP, SELECT) underpin its approvals.
14 min read · Updated
-
Sermorelin: what it is, how it works and what studies have found
Sermorelin is a synthetic 29-amino-acid peptide amide identical to the first 29 residues of human growth hormone-releasing hormone (GHRH). It binds the GHRH receptor on pituitary somatotrophs and stimulates growth hormone release. FDA approved it in 1990 (diagnostic) and 1997 (paediatric GH deficiency); the products were discontinued in 2008, not for safety or effectiveness reasons.
13 min read · Updated
-
Survodutide: what it is, how it works and what studies have found
Survodutide (BI 456906) is an investigational 29-amino-acid acylated peptide that activates both the glucagon receptor and the GLP-1 receptor. It has completed phase 3 obesity trials (SYNCHRONIZE-1, SYNCHRONIZE-2 and SYNCHRONIZE-MASLD) and is in phase 3 for MASH. No regulator had approved it as of October 2026.
14 min read · Updated
-
TB-500: what it is, how it works and what studies have found
TB-500 is a common name, not an approved drug name. FDA describes it as Ac-LKKTETQ, the N-acetylated residues 17-23 of thymosin beta-4 (889 g/mol), although full-length 43-residue thymosin beta-4 is sold under the same name. Human trials exist only for thymosin beta-4; FDA found no human studies of TB-500 itself. WADA prohibits both under S2.
14 min read · Updated
-
Teduglutide: what it is, how it works and what studies have found
Teduglutide is a 33-amino-acid analogue of glucagon-like peptide-2 (GLP-2) in which glycine replaces alanine at position 2, making it resistant to DPP-4. It activates the GLP-2 receptor in the gut. It was approved in the EU (August 2012) and US (December 2012) for short bowel syndrome dependent on parenteral support.
12 min read · Updated
-
Tesamorelin: what it is, how it works and what studies have found
Tesamorelin is a synthetic analogue of human growth hormone-releasing hormone: the full 44-amino-acid GHRH sequence with a trans-3-hexenoyl group on the N-terminal tyrosine. It stimulates pituitary growth hormone release, resists DPP-4 cleavage, and was FDA approved in November 2010 for excess abdominal fat in HIV-infected adults with lipodystrophy.
12 min read · Updated
-
Tirzepatide: what it is, how it works and what studies have found
Tirzepatide is a 39-amino-acid peptide based on the GIP sequence that activates both the GIP and GLP-1 receptors. Two Aib residues resist DPP-4, and a C20 fatty di-acid on lysine 20 binds albumin, giving an elimination half-life of about 5 days. The SURPASS and SURMOUNT phase 3 programmes support its approvals.
13 min read · Updated
Lyophilization
Freeze-drying peptides: freezing, primary and secondary drying, excipients, cycle development and vials.
-
Aseptic fill finish explained: how sterile peptide vials are filled, closed and released
Aseptic fill finish is the manufacture of a sterile product from components that were sterilised separately: the solution is sterile-filtered, filled into sterilised vials and closed in a Grade A zone, because the product cannot be sterilised in its final container. Regulators accept it when terminal sterilisation would degrade the product, as is usual for peptides.
15 min read · Updated
-
Peptide lyophilization (lyophilisation): a practical guide to freeze-drying peptide APIs
How peptide lyophilization (freeze-drying) works: freezing, primary and secondary drying, Tg′ and collapse temperature, excipients, cycles and vials.
11 min read · Updated
-
What is a lyophilized peptide? Freeze-drying explained, from the three stages to the finished cake
A lyophilized peptide is a peptide that has been freeze-dried: dissolved, frozen, then dried under vacuum so the ice sublimes and bound water desorbs. What remains is a porous solid, or cake, that is usually far more stable than the same peptide in solution and is dissolved again before use.
13 min read · Updated
Handling and storage
Stability, storage temperatures, reconstitution and shipping of peptide material.
-
How do peptides degrade? Degradation pathways, warning signs and stability testing
Peptides degrade chemically and physically. The main chemical routes are deamidation (fastest at Asn-Gly), aspartate isomerisation, oxidation of Met, Cys and Trp, disulfide scrambling, backbone hydrolysis, diketopiperazine and pyroglutamate formation, and racemisation. Physically, peptides aggregate or form fibrils. pH, temperature, moisture, oxygen, metals and light set the rates.
16 min read · Updated
-
How to reconstitute lyophilized peptides in the lab: solvent choice, stock solutions, storage and troubleshooting
To reconstitute a lyophilized peptide for laboratory work, warm the closed vial to room temperature, read the net peptide content on the certificate, choose the mildest solvent the sequence allows (water or buffer, then dilute acid, dilute base or a minimal organic co-solvent), add it to reach a defined assay stock concentration, mix gently, then aliquot and freeze.
14 min read · Updated
-
Lyophilized (lyophilised) peptide stability and storage: how long a peptide API lasts and how to keep it
How long a lyophilized peptide API lasts, what degrades it, which storage temperatures ICH Q1A(R2) defines, how stability is tested and how to ship it safely.
9 min read · Updated
-
Shipping peptides in the cold chain: packaging, dry-ice rules, receiving checks, excursions and long-term storage
Peptides should travel at the condition their stability data supports. Lyophilized peptides are often shipped cool or, where data allows, at ambient temperature with a data logger; peptide solutions usually travel frozen on dry ice. Air shipments with dry ice fall under IATA rules as UN 1845, Class 9, and every arrival should be checked against the logger before storage.
14 min read · Updated
Quality and testing
Specifications, impurities, certificates of analysis and the analytical tests behind them.
-
Endotoxin testing for peptides: LAL, recombinant factor C, limits and interference
Endotoxin in peptides is measured with the bacterial endotoxins test: Limulus amebocyte lysate (LAL) in gel-clot, turbidimetric or chromogenic form, or recombinant factor C (rFC). Results are reported in endotoxin units per mg or mL against a limit set for the intended use. Sterility and bioburden are separate tests and do not replace it.
14 min read · Updated
-
How to read a peptide COA: every test explained, red flags and how to verify it
A peptide COA should be specific to your batch and list each test with its method, acceptance limit and numerical result: identity by mass spectrometry, HPLC purity with the chromatogram, peptide content, water, counter-ion, residual solvents and, where relevant, endotoxin. Verify it by matching the lot number, identifying the laboratory and checking its accreditation.
14 min read · Updated
-
How to read a semaglutide API certificate of analysis (COA)
A test-by-test guide to a semaglutide API COA: identity, assay, purity, peptide content, water, acetate, residual solvents, endotoxin and the specs behind them.
9 min read · Updated
-
HPLC method validation under ICH Q2(R2) and Q14: a practical guide for peptide purity and assay methods
ICH Q2(R2), adopted on 1 November 2023 and in effect in the EU since 14 June 2024, sets how an HPLC method is shown fit for purpose. A peptide purity or assay method is validated for specificity, reportable range and response, accuracy, precision and, for impurities, quantitation limit, with robustness studied during development under ICH Q14.
14 min read · Updated
-
Net peptide content vs HPLC purity: how amino acid analysis and mass balance measure the peptide in the vial
Net peptide content is the percentage of a powder's weight that is the peptide itself. HPLC purity is only the main peak's share of peptide-related material. Water, counter-ions such as TFA or acetate and residual solvents make up the rest, so a 99% pure peptide can be well under 80% peptide by weight.
13 min read · Updated
-
Peptide API impurities and specifications: thresholds, tests and what regulators expect in 2026
How peptide API impurities are classified and controlled: why ICH Q3A does not apply, Ph. Eur. 0.1/0.5/1.0% thresholds, FDA's 2026 peptide guidance and what a specification covers.
8 min read · Updated
-
Peptide counter-ions: TFA vs acetate vs hydrochloride, and why the salt form changes your results
A synthetic peptide with basic residues is isolated as a salt. Fmoc synthesis and reversed-phase purification both use trifluoroacetic acid, so the default is a trifluoroacetate salt. Most approved peptide drugs are acetates instead. The counter-ion adds mass, lowers net peptide content and can change biological results.
14 min read · Updated
-
Peptide mass spectrometry: how ESI, MALDI, MS/MS and LC-MS confirm a peptide's identity
Mass spectrometry identifies a peptide by measuring the mass-to-charge ratio of its ions. ESI or MALDI turns the peptide into gas-phase ions, the intact mass is compared with the theoretical monoisotopic or average mass, and MS/MS fragments the backbone into b and y (or c and z) ions that read out the sequence.
12 min read · Updated
-
Peptide purity testing: how HPLC, mass spectrometry and amino acid analysis work together
Peptide purity is usually measured by reversed-phase HPLC with UV detection at 210–220 nm: the main peak's share of all detected peak area. Mass spectrometry confirms the peak is the right molecule, and amino acid analysis or nitrogen content shows how much of the powder is actually peptide. A purity figure alone answers only the first question.
16 min read · Updated
Synthesis and manufacturing
How peptides are made: solid-phase, liquid-phase and hybrid routes, purification and scale-up.
-
Peptide modifications for stability and half-life: lipidation, PEGylation, Aib, cyclisation and fusion
Native peptides are cleared in minutes. Modifications fix that in two ways: blocking proteolysis, with non-natural residues such as Aib, D-amino acids, cyclisation and terminal capping; and slowing renal clearance, with fatty acid acylation or PEGylation that enlarge the molecule or bind it to albumin.
16 min read · Updated
-
Peptide purification: preparative HPLC, ion exchange and the yield versus purity trade-off
Peptides are purified by preparative chromatography. Crude peptide from synthesis is loaded on a reversed-phase column and eluted with a water and acetonitrile gradient, usually followed by an orthogonal ion-exchange step. Pure fractions are pooled, the counter-ion is set, the cosolvent is removed and the peptide is lyophilized.
15 min read · Updated
-
Peptide synthesis: how peptides are made, from the first resin bead to a purified kilogram
Peptide synthesis builds a chain of amino acids in a controlled order. Most peptides are made by solid-phase peptide synthesis (SPPS), where the chain grows on a resin through repeated deprotection and coupling cycles, then is cleaved, purified by preparative chromatography and isolated, usually by lyophilization.
18 min read · Updated
-
SPPS vs LPPS vs hybrid: how peptide APIs are manufactured, and why the route matters to buyers
Solid-phase, liquid-phase and hybrid peptide synthesis compared for API buyers: chemistry, length limits, impurities, scale, solvent use and regulatory impact.
9 min read · Updated
-
What is a peptide bond? Formation, structure, hydrolysis and laboratory synthesis
A peptide bond is the amide bond that links two amino acids: the carboxyl group of one joins the amino group of the next and a molecule of water is released. Resonance gives the C–N bond partial double-bond character, so the peptide group is planar and almost always trans.
12 min read · Updated
-
What is a peptide? Definition, types, functions and how peptides are made
A peptide is a chain of amino acids joined by amide links called peptide bonds. IUPAC calls chains of fewer than about 10 to 20 residues oligopeptides and longer chains polypeptides. Many hormones, such as oxytocin and GLP-1, are peptides, and more than 80 peptide drugs have reached the market.
13 min read · Updated
Regulatory and APIs
What a peptide API is, EU and US regulatory pathways, patents and exclusivity.
-
Generic semaglutide: EU and US regulatory pathways, and what API makers must show
How generic semaglutide is filed in the EU and US: generic vs hybrid, 8+2+1 protection, ANDA vs 505(b)(2), synthetic vs recombinant API, API maker duties.
10 min read · Updated
-
GMP peptides explained: what GMP grade means, GLP vs GMP, and research grade vs GMP grade
A GMP grade peptide is one manufactured and released under good manufacturing practice for active pharmaceutical ingredients, set out internationally in ICH Q7: an independent quality unit, batch records, validated processes, change control and a batch Certificate of Analysis. Research grade describes intended laboratory use, not a regulated standard. GLP governs nonclinical safety studies, not manufacture.
15 min read · Updated
-
ICH Q7 explained: GMP for active pharmaceutical ingredients, chapter by chapter, with peptide APIs in focus
ICH Q7 is the international good manufacturing practice guide for active pharmaceutical ingredients, adopted at Step 4 on 10 November 2000. Its 20 chapters cover quality management, facilities, documentation, materials, production, laboratory controls, validation, change control and clinical-trial APIs. FDA, the EU and PIC/S inspectorates use it as the GMP standard for API manufacturers.
15 min read · Updated
-
Semaglutide patent expiry by country: dates, status and what it means for API buyers
When semaglutide's compound protection ends in India, China, Canada, Brazil, the US, EU, UK and Japan, with primary sources, and what it means for API buyers.
8 min read · Updated
-
What is a drug master file? DMF, ASMF and CEP for a peptide API, with the CTD Module 3 sections
DMF stands for drug master file: a confidential submission to FDA describing how a drug substance, packaging or excipient is made and controlled. A peptide API maker files a Type II DMF in CTD Module 3 format and authorises customers to reference it by letter. FDA does not approve DMFs; it reviews them with the applications that cite them.
13 min read · Updated
-
What is a peptide API? API vs drug substance explained
A peptide API is the active ingredient of a peptide medicine. How ICH, FDA and EU law define API, drug substance and active substance, and where peptides fit.
9 min read · Updated
-
What is EU GMP Annex 1? The 2022 sterile manufacturing rules explained, clause by clause
EU GMP Annex 1 is the European Commission's guideline for manufacturing sterile medicinal products. Its full 2022 revision, identical in substance to PIC/S Annex 1, applied from 25 August 2023, with clause 8.123 on lyophilizer sterilisation following on 25 August 2024. It centres on a site-wide contamination control strategy, risk management and barrier technology.
14 min read · Updated
-
What is ICH Q11? Starting materials, control strategy and Q6A/Q6B specifications for peptide drug substances
ICH Q11 is the ICH guideline on developing and manufacturing drug substances, adopted on 1 May 2012. It covers process development, starting material selection, control strategy and how this is presented in CTD sections 3.2.S.2.2–3.2.S.2.6. ICH Q6A and Q6B cover specifications, but only partly fit synthetic peptides, so EMA's 2025 peptide guideline fills the gaps.
13 min read · Updated
CDMO and sourcing
Outsourcing models and how to qualify a peptide supplier.
-
CDMO vs CMO vs CRDMO: what is the difference, and which one does a pharma buyer need?
What CMO, CDMO and CRDMO mean in pharma, how their scope differs, what GMP rules apply to every contract manufacturer, and which model a buyer needs.
9 min read · Updated
-
How to qualify a peptide API supplier: a documentation and audit checklist for EU and US buyers
A documentation and audit checklist for qualifying a peptide API supplier for EU and US filings: written confirmation, DMF/ASMF, GMP audit, impurities and agreements.
9 min read · Updated
-
Lyophilization services: how to choose a contract lyophilization CMO, and what to send them
Choose a lyophilization CMO on evidence: a tech-transfer process that asks for your thermal data and analytical methods, cycle development and scale-up based on measured equipment parameters, a sterile fill-finish line with current media-fill results, and a release-testing plan covering residual moisture, reconstitution, sterility, endotoxin and container closure integrity. Contract terms should cover subcontracting and audit rights.
12 min read · Updated
-
What is WHO-GMP certification? Who issues it, what it covers and how buyers verify it
A WHO-GMP certificate is issued by a national regulator, not by WHO. It states that a site follows WHO's good manufacturing practice guidelines, usually alongside a Certificate of Pharmaceutical Product under the WHO Certification Scheme. In India it follows a joint inspection by CDSCO and the State Licensing Authority. WHO prequalification is a separate, product-level WHO assessment.
12 min read · Updated
Molecule reference pages
CAS number, structure data, regulatory status and sources for each peptide we supply.
Discuss a peptide API or lyophilisation project
Tell us the molecule, quantity and documentation you need, or the API you want lyophilised. Our team will come back to you directly.
Send a project enquiry- Peptide APIs & CMO services
- Peptide API supplier (5 APIs)
- Semaglutide API supplier
- Tirzepatide API supplier
- Research peptides (RUO), >99% purity
- GLP-1 research peptides
- Custom peptide synthesis
- Peptide lyophilisation (lyophilization) services
- Biosimilar and protein lyophilisation
- Lyophilisation for European companies
- Peptide CDMO & contract manufacturing
- Peptide API supplier for Europe
- Peptide API supplier for the USA