Thymosin alpha-1 (thymalfasin): a thymic peptide approved in more than 35 countries, no UK marketing authorisation, and four decades of clinical trials
One of the most clinically studied peptides in the field — licensed abroad, unlicensed here, and routinely confused with TB-500.
Peptide-based vaccines explained: neoantigen and synthetic long-peptide vaccines, and a class that sits inside clinical trials
Synthetic peptide vaccines deliver defined amino-acid sequences to the immune system. In oncology the leading approach is personalised and neoantigen-directed; across the class the record is immunogenicity, not yet clinical benefit.
Corticorelin and CRH: the hypothalamic releasing factor at the apex of the HPA axis
One hypothalamic peptide sits at the top of the HPA axis: 41 amino acids that drive ACTH and cortisol. Its synthetic form, corticorelin, is a specialist diagnostic and a research compound — and the drug-development effort around its receptor has been led by small molecules, not peptides.
UK first in Europe to authorise an oral GLP-1 tablet: the MHRA authorisations, and what they do not change
The MHRA has authorised the oral GLP-1 receptor agonist orforglipron from Drug Discovery World, following the earlier UK authorisation of an oral semaglutide tablet. One of those molecules is a peptide and the other is not — and neither authorisation moves the research-use-only boundary.
Why most peptides are injected: the oral-absorption problem, permeation enhancers, and the peptides licensed to be swallowed
Peptides are poor oral drugs by design — enzymes digest them, their size and polarity stop them crossing the gut wall, and the liver removes what survives. A small number of licensed products get around this with chemical enhancers. That engineering, not the 'oral peptide' claim on a research vial, is what makes swallowing a peptide work.
Retatrutide TRIUMPH-1 published in NEJM: 28.3% mean weight loss at 80 weeks, and 30.3% at 104
The pivotal general-obesity Phase 3 trial for the triple agonist has now been peer-reviewed and published: 2,339 participants, a surgical-level mean weight reduction at the 12 mg dose, and a prespecified extension in which weight continued to fall beyond 80 weeks.
Glucagon: a UK-licensed counter-regulatory peptide — and the third receptor arm inside the triple agonists
Glucagon is the proglucagon-gene hormone that opposes insulin, is licensed in the UK for severe hypoglycaemia, and now sits inside the multi-receptor obesity candidates as the glucagon-receptor component.
GLP-1 receptor agonists and alcohol use disorder: what the semaglutide trials do and do not show
Oral semaglutide reduced heavy drinking days in a 50-person Phase 2 trial, but missed its primary endpoint. No GLP-1 receptor agonist is licensed in the UK for alcohol use disorder.
Humanin: a mitochondrial-derived cytoprotective peptide with a deep preclinical record and no controlled human trial
A 24-amino-acid peptide encoded in mitochondrial DNA, with a deep cytoprotective preclinical literature, a far more potent analogue in HNG, and no controlled human trial.
CagriSema Phase 3: 21.0% weight loss in REDEFINE 9, and a head-to-head win over tirzepatide in REIMAGINE 5
On 21 September 2026 Novo Nordisk reported topline Phase 3 results for once-weekly CagriSema: 21.0% mean weight loss versus 2.0% placebo at 68 weeks in REDEFINE 9, and superior weight loss over tirzepatide 5 mg in REIMAGINE 5. Both readouts are sponsor-reported topline figures, and CagriSema remains unlicensed in the UK.
Survodutide Phase 3: 16.6% mean weight loss in SYNCHRONIZE-1 and a liver-fat signal in SYNCHRONIZE-MASLD
The dual glucagon/GLP-1 receptor agonist is the first of its class to publish Phase 3 obesity data in the New England Journal of Medicine. It has not been filed with the MHRA, and no UK licence exists.
GLP-1 receptor agonists and lean mass: what the body-composition trials actually report
A recurring question around GLP-1 medicines is how much of the weight lost is fat and how much is lean tissue. The trial literature gives concrete numbers — and some clear limits.
GLP-1 medicines and acute pancreatitis: the MHRA's strengthened warning, and what the randomised evidence shows
In January 2026 the MHRA strengthened warnings on acute pancreatitis for all GLP-1 and dual GLP-1/GIP receptor agonists in the UK, after rare necrotising and fatal reports and 1,296 Yellow Card pancreatitis reports since 2007. This explainer sets the regulatory warning beside the randomised-trial evidence, which has not shown a clear increase in risk.
Acmopatide (CT-868): a dual GLP-1/GIP peptide that met its Phase 2 endpoint in type 1 diabetes — and was dropped anyway
A once-daily dual GLP-1/GIP agonist produced a modest HbA1c reduction, dose-dependent weight loss and a fall in insulin requirement in adults with type 1 diabetes. Roche discontinued it four months later.
Petrelintide ZUPREME-1: Phase 2 primary endpoint published — 9.8% weight loss at 5 mg, with a GI tolerability profile the amylin class has not shown before
The Lancet Diabetes & Endocrinology has published the ZUPREME-1 primary-endpoint analysis for the selective amylin-receptor agonist — and what the tolerability signal does and does not establish.
A vial sold as retatrutide contained no retatrutide — and eight times the semaglutide: the TGA's oesophageal-tear case
Australia's medicines regulator tested a product sold as the weight-loss peptide retatrutide after a consumer was hospitalised. It found a different drug entirely — at a dose roughly eight times higher than in assessed semaglutide products.
Amylin receptor selectivity explained: AMYR agonists versus dual amylin/calcitonin (DACRA) agonists
Why the current amylin class divides on one pharmacological question — how broadly a peptide engages the calcitonin receptor — and what that does and does not predict clinically.
Angiotensin II (Giapreza): a peptide vasopressor with a UK marketing authorisation
Angiotensin II is an eight-amino-acid peptide — the effector hormone of the renin-angiotensin-aldosterone system. As Giapreza it holds a UK marketing authorisation for refractory hypotension in distributive shock. It is a useful reminder that a peptide can be a fully licensed medicine, not only a research reagent.
Calcitonin and the calcitonin-family peptides: salmon calcitonin, amylin and CGRP — one receptor family, and a UK withdrawal
Calcitonin was among the first peptide hormones to be developed as a medicine. Its intranasal form was withdrawn across Europe in 2012 after a long-term cancer signal; an injectable form survives for short-term use. This explainer sets out the receptor family it shares with amylin and CGRP, and the UK position.
FOXO4-DRI: a senolytic peptide with a landmark mouse study — and no human trial
A D-retro-inverso peptide that selectively clears senescent cells in mice, and the evidence and regulatory questions that stand between that record and any human use.
The 'research use only' loophole, again: a Lincoln criminologist calls for tighter peptide sale rules — and the MHRA restates its case-by-case test
An academic wants the research-use-only route closed; the regulator repeats that classification turns on the facts, not the label.
Muscle preservation beside semaglutide: the COURAGE Phase 2 readout, and the myostatin peptide class that came before it
A Phase 2 readout puts an antibody, not a peptide, first in the myostatin pathway to preserve lean mass beside a GLP-1 receptor agonist — a research readout, unlicensed, and reported here for the class context it supplies.
Myostatin inhibition: ACE-031 and follistatin-344 — a class that reached human trials, then stopped
One decoy receptor and one binding protein can both take the brake off skeletal muscle growth. Both reached human studies; one was stopped for vascular safety signals, the other never advanced past gene therapy.
C-peptide: a proinsulin fragment with a small, mixed human record in diabetic neuropathy and kidney disease — and no UK licence
For decades C-peptide was treated as an inert by-product of insulin processing. A small set of short, older trials in type 1 diabetes reports nerve and kidney signals — and the largest of them met one endpoint and missed the others.
IGF-1 and IGF-1 LR3 explained: a licensed recombinant for a rare growth disorder, and an unlicensed research analogue with no human trial record
A recombinant human IGF-1 holds an EU marketing authorisation for a rare growth disorder. The long-acting analogue sold as a research reagent holds no licence — and no human trial record.
Growth-hormone secretagogues compared: GHRH analogues, ghrelin-receptor agonists and the GHRP family — one pituitary output, three routes, no UK-licensed member
Sermorelin, tesamorelin, CJC-1295, ipamorelin, GHRP-6 and hexarelin act through two different receptors to raise growth-hormone release. Most of the human literature measures the hormone, not an outcome.
Insulin analogues compared: recombinant human insulin, the rapid-acting analogues and the long-acting analogues
Every insulin in UK clinical use is a prescription-only peptide medicine with a marketing authorisation - the one class where the licensing picture, not the evidence gap, is the whole story.
Survodutide SYNCHRONIZE-2: Phase 3 in obesity and type 2 diabetes — 13.1% weight loss, an 18% GI discontinuation rate, and no licence anywhere
An investigational dual glucagon/GLP-1 agonist, two estimands that tell different stories, and a tolerability figure that shapes how the result should be read.
Metreleptin (Myalepta): a UK-licensed leptin-replacement peptide — and the rare-disease evidence base behind it
A ligand-replacement peptide that holds a marketing authorisation, a narrow rare-disease indication, and an open-label pivotal evidence base.
ACTH and tetracosactide: the corticotropin axis, the MC2R receptor, and a UK-licensed synthetic ACTH fragment
One pituitary hormone, one synthetic fragment, and the only melanocortin receptor that sits on the adrenal gland.
ACHIEVE-3: orforglipron beat oral semaglutide head-to-head — the first randomised comparison of two oral GLP-1 routes
A 52-week Phase 3 trial put a non-peptide oral GLP-1 against a peptide oral GLP-1 in type 2 diabetes. The non-peptide won on HbA1c and weight; tolerability stayed within the class profile.
GLP-1 medicines and the reward circuit: what the emotional-blunting reports do and do not show
Some users describe emotional flattening on GLP-1 medicines and the unapproved triple agonist retatrutide. The mechanism is plausible and preclinical; the human outcome data do not exist yet.
EloraTZP: an amylin agonist plus tirzepatide produced 23.3% mean weight loss in a Phase 2b trial — with a tolerability question attached
Lilly's combination of eloralintide and tirzepatide cleared its Phase 2b endpoints at EASD 2026. The discontinuation rates are the part that remains unresolved.
Petrelintide enters Phase 3: Zealand's ZUPREME programme will test the amylin analogue in about 7,000 people
Three registrational trials, a Roche combination with CT-388, and a primary efficacy readout set for week 64 — the amylin class is moving into its largest test yet.
Amycretin is now zenagamtide: Novo Nordisk's unimolecular GLP-1/amylin agonist enters Phase 3 for obesity and type 2 diabetes
The compound formerly known as amycretin carries a new name, a Phase 3 programme in obesity that began in the first quarter of 2026, and Phase 2b type 2 diabetes data presented at ADA 2026.
NICE TA1026 and the tirzepatide commissioning gap: a positive appraisal, a phased NHS rollout, and a voluntary GP indicator
NICE recommends tirzepatide for overweight and obesity in specialist weight-management services, but NHS England's interim commissioning guidance narrows primary-care access, and from 1 April 2026 prescribing sits in the 2026/27 GP contract as an optional QOF indicator.
The MHRA's largest recorded seizure: a clandestine GLP-1RA factory in Northampton, counterfeit tirzepatide and unlicensed retatrutide
A clandestine Northampton facility producing counterfeit tirzepatide pens and unlicensed retatrutide puts the UK enforcement picture — and the limits of the 'research use only' label — in sharp focus.
Who regulates peptides in the UK? The medicines boundary, the MHRA, and the regulators behind the 'research use only' label
There is no single UK law that says whether a peptide is legal. Classification turns on what the product is, how it is presented and how it is supplied — and more than one body enforces the line.
Retatrutide TRIUMPH-4 Phase 3: 28.7% mean weight loss and a marked knee-osteoarthritis pain signal
The first Phase 3 readout for the triple agonist peptide — and what it does and does not establish.
Maridebart cafraglutide (MariTide): an antibody–peptide conjugate that blocks GIP while activating GLP-1
A different molecular format and an inverted receptor logic — what the Phase 2 record shows, and why it cannot be compounded.
BPC-157 reaches its first randomised controlled trial: a Phase 2 study in acute hamstring strain
A double-blind, placebo-controlled Phase 2 trial of BPC-157 (NCT07437547) began recruiting in February 2026 — the first properly controlled human trial for a compound whose evidence base has until now been almost entirely preclinical.
MHRA, ASA and GPhC warn against promoting unlicensed and pipeline weight-management medicines
On 18 June 2026 the MHRA, the Advertising Standards Authority and the General Pharmaceutical Council issued a joint warning: promoting unlicensed medicines, products still under regulatory review, or licensed prescription-only GLP-1 products to the public breaches UK medicines advertising rules.
Balixafortide and the CXCR4 peptide antagonists: a selective cyclic peptide that reached Phase 3 and missed
CXCR4 is the chemokine receptor that governs how cells home — and one of the routes a tumour can use to spread. Balixafortide is the peptide antagonist that took the target furthest into oncology trials.
Romiplostim (Nplate): a peptibody thrombopoietin-receptor agonist — a UK-licensed Fc-peptide fusion
An Fc-peptide fusion protein that activates the thrombopoietin receptor, and one of the few peptides in the UK licensed-medicines set with a randomised human dataset behind it.
Romidepsin and plitidepsin compared: two marine-derived depsipeptides licensed elsewhere — but not in the UK
Two depsipeptides from marine organisms, two different molecular targets, and a UK licensing picture that inverts the usual assumption about 'approved' oncology peptides.
Glatiramer acetate (Copaxone): a heterogeneous synthetic polypeptide licensed in the UK for relapsing multiple sclerosis
The UK-licensed peptide set is smaller than the market implies. Glatiramer acetate is one of its odder members: a defined mixture rather than a defined sequence.
Avexitide (exendin 9-39): a GLP-1 receptor antagonist — the inverse of the incretin agonists, and unlicensed in the UK
The same peptide scaffold that produced exenatide also produced a competitive GLP-1 receptor antagonist. Phase 2 and Phase 3 data exist; an MHRA licence does not.
Natriuretic peptides as research compounds: carperitide, nesiritide and the ANP/BNP class — none licensed in the UK
A 28-amino-acid cardiac hormone, a recombinant B-type analogue and a neprilysin-inhibiting small molecule converge on the same cGMP pathway. Only one of the three carries a UK marketing authorisation.
Peptide antibiotics: vancomycin, daptomycin and colistin — three licensed scaffolds, three mechanisms
Antimicrobial peptides are among the oldest licensed peptide drugs and the least discussed in the grey-market conversation. Vancomycin (a glycopeptide), daptomycin (a cyclic lipopeptide) and colistin (a polymyxin) are all UK prescription-only medicines with distinct mechanisms — cell-wall binding, calcium-dependent membrane depolarisation, and lipid A disruption. This explainer sets out the three mechanisms, the UK licensing and stewardship picture, and why a licensed class does not license the rest of the field.
Icatibant (Firazyr): a UK-licensed decapeptide that blocks the bradykinin B2 receptor
Icatibant (Firazyr) is a synthetic decapeptide and a selective bradykinin B2 receptor antagonist — one of the few peptides in this reference that holds a UK marketing authorisation.
Purity is not identity: how to read a peptide certificate of analysis
An HPLC purity figure and a mass-spectrometry identity check answer two different questions. Net peptide content answers a third — and it is the one most often missing.
Enicepatide (CT-388): a signalling-biased dual GLP-1/GIP agonist with two positive Phase 2 readouts — and no UK licence
Roche's once-weekly dual agonist reported 22.5% placebo-adjusted weight loss at 48 weeks in obesity and met both primary endpoints in type 2 diabetes. It remains investigational in the UK.
Peptide receptor radionuclide therapy: lutetium-177 dotatate and the somatostatin-receptor peptide as a delivery system
The same receptor affinity that makes octreotide a medicine is what makes DOTATATE a vehicle for radiation.
Incretin mimetics compared: GLP-1, dual GIP/GLP-1 and triple receptor agonists — one class, one UK licensing picture
A single-receptor agonist, a dual agonist and a triple agonist share a name and a mechanism. Only some of them hold a UK licence.
Amylin analogues compared: pramlintide, cagrilintide and the long-acting generation behind CagriSema
A satiety pathway distinct from the incretins — and a class with one old analogue, one emerging combination, and no UK licence.
MHRA Drug Safety Update: semaglutide and the very rare NAION eye risk
The MHRA's February 2026 Drug Safety Update records NAION as a very rare reported risk of semaglutide and advises urgent ophthalmological assessment for sudden vision loss.
Bortezomib and carfilzomib compared: two peptide-based proteasome inhibitors that set the UK-licensed evidence ceiling
Bortezomib and carfilzomib are peptide-based proteasome inhibitors licensed in the UK as prescription-only medicines for multiple myeloma. One binds reversibly (a dipeptide boronic acid); the other irreversibly and more selectively (a tetrapeptide epoxyketone). Both sit at the evidence ceiling for the peptide field — randomised Phase 3 data and NICE appraisal — and their safety profiles diverge on neuropathy versus cardiac events.
Cerebrolysin: a porcine brain-derived peptide mixture with a large trial record and a contested verdict
Cerebrolysin is a porcine brain-derived peptide hydrolysate licensed in several non-UK jurisdictions but not by the MHRA. Its trial record is large and its verdict is contested: a positive post-stroke rehabilitation trial and a neutral confirmatory stroke trial sit beside a Cochrane review that finds no demonstrated clinical benefit. Evidence grade: Moderate.
Davunetide (NAP/AL-108): an intranasal tau-directed peptide whose pivotal trial missed every endpoint
Derived from ADNP and developed as a tau-directed neuroprotective agent, davunetide produced a large negative Phase 2/3 in progressive supranuclear palsy — yet the same molecule is now in a company-reported Phase 3 for ADNP syndrome.
Eli Lilly sues six US sellers of retatrutide: an enforcement playbook that reaches UK supply chains
On 12 August 2026 the drugmaker filed six US lawsuits against alleged 'research-use-only' sellers, a med spa and a compounding pharmacy — while UK seizures of unlicensed weight-loss peptides continue under the MHRA's Criminal Enforcement Unit.
GLP-1s and Alzheimer's: semaglutide's Phase 3 EVOKE failure beside liraglutide's mixed Phase 2b signals
Two randomised trials of GLP-1 receptor agonists in Alzheimer's disease reported opposing headline results within weeks of each other. Neither supports a licensed indication, and the UK position is unchanged: these are prescription medicines licensed for diabetes and weight management, not dementia.
UCLA scoping review of six recovery peptides: 565 studies, little human evidence, and a flagged MK-677 heart-failure signal
A US orthopaedic team screened 565 studies on BPC-157, TB-500, CJC-1295, MK-677, ipamorelin and GHK-Cu — and found the marketing running well ahead of the human data.
Larazotide acetate (AT-1001): the tight-junction peptide that reached Phase 3 in coeliac disease — and missed its primary endpoint
The most clinically advanced attempt to drug intestinal permeability, and what its Phase 3 result actually tells researchers.
CagriSema: a two-peptide amylin–GLP-1 combination with Phase 3 weight-loss data and no UK licence
A fixed-dose amylin plus GLP-1 peptide combination whose Phase 3 programme met its obesity and type 2 diabetes endpoints, missed an 84-week non-inferiority target against tirzepatide, and holds no MHRA marketing authorisation.
MHRA investigates UK peptide clinics over medicinal claims: what the 'research purposes' line actually means
The regulator opened an inquiry in April 2026 after a Guardian investigation found clinics advertising unregulated peptides with therapeutic claims — and confirmed that a 'research purposes' label does not exempt a supplier that promotes a product for human use.
ARA-290 (cibinetide): an EPO-derived innate-repair-receptor peptide with Phase II signals and no Phase III
Engineered from the helix B surface of erythropoietin, ARA-290 activates the innate repair receptor without stimulating red-cell production. Two small Phase II programmes in sarcoidosis and diabetic neuropathy produced promising but unreplicated signals; the developer has since ceased operations and no Phase III has been run.
Elamipretide (SS-31): a mitochondria-targeted tetrapeptide with one conditional US approval, a failed Phase 3, and no UK licence
The first cardiolipin-directed peptide to be approved anywhere was cleared on a surrogate endpoint in an ultra-rare disease — after its pivotal Phase 3 missed both primary endpoints. What the evidence shows, and why it remains unlicensed in the UK.
Six research peptides cleared a US compounding hurdle in July 2026 — what that does and does not mean under UK law
The FDA's Pharmacy Compounding Advisory Committee voted to recommend six peptides for the 503A Bulks List. It is a US compounding decision, not a drug approval — and the UK operates a different framework entirely.
The UK's clinical-trials rules changed on 28 April 2026: what the CTIMP reforms mean for peptide research
The largest package of UK clinical-trial regulatory reform in more than 20 years came into force this spring. Here is what changed — and why it matters to anyone following, or running, peptide trials.
GHK-Cu: a copper tripeptide graded Moderate — what the research does and does not show
One of the few research peptides graded Moderate, GHK-Cu has a deep mechanistic literature and a smaller, largely industry-funded human record. Here is where the evidence is strong and where it thins out.
Kisspeptin: a Moderate-grade reproductive neuropeptide sitting upstream of GnRH
The KISS1R agonist at the apex of the HPG axis — what the Phase 1/2 human data actually measures, why a single research group supplies most of it, and how the UK regulates it.
TB-500 and BPC-157 compared: the same Limited grade, two different literatures and two different UK footings
Both are graded Limited, both are unlicensed in the UK — but one has a defined molecular target and a handful of human studies, the other an unusually broad preclinical record and essentially none.
Aviptadil (RLF-100/Zyesami): a synthetic VIP with orphan-drug designations, a Phase 3 pivot — and a trial halted for futility
Vasoactive intestinal peptide reached Phase 3 in COVID-19 respiratory failure on the strength of a small pre-COVID respiratory literature. That trial did not clear its futility bar, and the earlier sarcoidosis and lung-injury record is thinner and older than the pipeline narrative suggested.
Oxytocin: a licensed obstetric hormone wrapped in a contested social-cognition literature
Oxytocin is one of the few peptides with a fully licensed UK medicine behind it — and a separate, much noisier intranasal research literature that the largest trials have largely failed to confirm.
PT-141 (bremelanotide): a US-licensed melanocortin agonist with no UK licence — what the Phase 3 evidence does and does not show
Bremelanotide is the only centrally-acting melanocortin agonist to reach market anywhere, licensed in the United States for hypoactive sexual desire disorder in premenopausal women. Its two pivotal trials were statistically positive but modest in effect, its label carries two hard edges, and it holds no UK or EU marketing authorisation.
AHK-Cu: a synthetic copper tripeptide with one strong laboratory signal and no human trial
It is sold as the "hair-specific" copper peptide and called clinically proven. The evidence is one 2007 laboratory study of cultured human follicles — real, mechanistically interesting, and nowhere near a clinical trial.
KPV (Lys-Pro-Val): a well-characterised preclinical anti-inflammatory tripeptide with no human trial record
KPV isolates the anti-inflammatory tail of α-MSH — a PepT1-transported, NF-κB-inhibiting tripeptide studied in colitis and skin models, and not yet in humans.
Melanocortin peptides compared: afamelanotide, melanotan II, bremelanotide and setmelanotide
A class comparison of the melanocortin peptides, and why their UK regulatory positions diverge so sharply.
Three Health Bill amendments would give the MHRA faster routes to update UK medicines law — and a future device licensing regime
Amendments tabled on 1 September 2026 would add information-sharing powers, make medicines legislation easier to update, and build towards a domestic medical-device licensing regime. They change nothing yet — here is what they do and do not propose.
Cosmetic peptides compared: argireline, matrixyl, SNAP-8 and leuphasyl — evidence and the UK cosmetics/medicines boundary
Acetyl hexapeptide-8, palmitoyl pentapeptide-4, SNAP-8 and leuphasyl are sold as cosmetics, not medicines. Here is what the topical evidence shows, where the delivery problem bites, and where UK law draws the cosmetics/medicines line.
GnRH analogues compared: agonists, antagonists and the paradoxical pharmacology behind a 40-year peptide drug class
Seven compounds in the Peptide Data register belong to one of medicine's most validated peptide drug classes — and all seven are UK prescription-only medicines, not research materials.
Somatostatin analogues compared: octreotide, lanreotide and pasireotide — receptor selectivity, half-life engineering, and a UK licensing picture that inverts the grey-market norm
Three licensed peptide medicines, two generations of receptor engineering, and a UK legal footing that is the opposite of the research-peptide grey market.
Sky News took grey-market peptides to a UK lab: a product labelled 99% pure tested at about 10% — and the 'research use only' defence is under scrutiny
An undercover purchase, a University of Manchester analysis, and a case-by-case statutory test the MHRA has not yet finished applying to the online peptide trade.
Engineering peptide half-life: lipidation, PEGylation, albumin binding and depot formulations
The chemistry that turns a molecule cleared in minutes into a once-weekly medicine — and why a longer half-life is not the same as a stronger effect.
Parathyroid hormone analogues compared: teriparatide, abaloparatide and palopegteriparatide — pulsatile anabolism, receptor-state selectivity and the same fragment engineered for opposite jobs
Three peptides act on the same receptor, yet one is pulsed for osteoporosis, one is tuned for transient receptor signalling, and one is deliberately made continuous as hormone replacement.
Bivalirudin and eptifibatide compared: two UK-licensed peptide medicines — a thrombin inhibitor and a platelet integrin blocker — that set the evidentiary ceiling for the peptide field
Both are short synthetic peptides used intravenously in NHS cardiac catheter laboratories. One inhibits thrombin directly; the other blocks the platelet GPIIb/IIIa receptor. Together they show why 'peptide' is a chemistry fact, not a statement about evidence or legal status.
Difelikefalin (Kapruvia): a peripherally restricted kappa-opioid peptide licensed in the UK for dialysis-associated pruritus
A peripherally restricted kappa-opioid peptide licensed in the UK in April 2022 as Kapruvia — and one of the handful of peptides in this reference that rests on Phase 3 data and a marketing authorisation.
Guanylate cyclase-C agonist peptides compared: linaclotide and plecanatide — one receptor, two analogues, and a UK licensing split
Two synthetic peptides, one intestinal receptor, and a licensing picture that separates the UK from the US: linaclotide is a UK prescription medicine, plecanatide is not authorised here at all.
Vasopressin analogues compared: desmopressin, terlipressin and argipressin — one nonapeptide, three receptors, three different UK-licensed jobs
Desmopressin, terlipressin and argipressin all descend from arginine vasopressin. Receptor selectivity, half-life engineering and prodrug design turn one nonapeptide into three licensed medicines with almost nothing in common at the bedside.
Counterfeit retatrutide in the UK: a BBC investigation, four MHRA raids and £200,000 frozen in a branded black market
Falsified, unlicensed retatrutide is circulating in the UK while the compound itself remains unapproved — what four MHRA raids, a £200,000 asset freeze and a BBC investigation establish about the black-market supply chain.
MHRA Yellow Card data on GLP-1 medicines: 216 suspected-link death reports among ~159,000 UK adverse-reaction reports
A wave of UK coverage in August 2026 put hundreds of deaths beside GLP-1 weight-management medicines. The underlying MHRA Yellow Card figures are reports of suspicion, not confirmed causes — but the pancreatitis signal behind them is real, and the MHRA has already acted on it.
GLP-2 analogues compared: teduglutide, glepaglutide and apraglutide — one gut-hormone receptor, three half-life strategies, and a single UK-licensed member
Native GLP-2 is cleared within minutes. Three leading analogues buy duration in three different ways — and only one of them holds a UK marketing authorisation.
Etelcalcetide (Parsabiv) versus cinacalcet: a peptide calcimimetic and a small molecule reach one receptor by two different routes — and split the UK four ways
A synthetic peptide calcimimetic with a NICE recommendation in England and a Scottish rejection — one calcium-sensing receptor, reached by two different binding sites.
Ziconotide (Prialt): a cone-snail conotoxin, an intrathecal N-type calcium-channel blocker, and a licensed peptide with no consumer route
A UK-licensed peptide analgesic built on a marine snail venom, delivered only by implanted intrathecal pump — and not recommended for routine NHS use in Wales.
Selank and Semax compared: two neuropeptides, one shared evidence problem
Both peptides carry a Russian clinical literature and no UK marketing authorisation. Here is what the human data actually shows — and where it runs out.
Serelaxin (recombinant human relaxin-2): a vasodilatory, antifibrotic peptide whose pivotal acute-heart-failure endpoint missed
Relaxin-2 has one of the most coherent preclinical cardiovascular mechanisms of any peptide — vasodilation, antifibrotic remodelling and organ protection via RXFP1 — yet the recombinant form, serelaxin, met its endpoint in one Phase 3 and missed it in the next. The gap between mechanism and outcome is the story.
DSIP (delta sleep-inducing peptide): a 1970s sleep factor with a small, dated, unreplicated human record
A nonapeptide isolated in 1977 on the strength of its slow-wave EEG signature. The human sleep literature that followed is small, mostly pre-1990, and never replicated to modern standards.
Epitalon and Pinealon: the pineal-peptide longevity literature and its evidentiary limits
Two short peptides from Russian gerontology research, marketed on telomere and neuroprotection claims. The human evidence is observational, regionally concentrated, and unreplicated outside its originating group.
How Peptide Data grades evidence: the four-tier system, and why the human-data ceiling keeps most research peptides at Limited
Every compound profile on Peptide Data carries one of four evidence grades. This is how those grades are assigned, what they do and do not mean, and why the strength of the human record — not the size of the bibliography — sets the ceiling.
Thymosin Alpha-1 and Thymalin compared: two thymic peptides graded Moderate for very different reasons
Both carry the same grade in our library — but one rests on randomised trials and a null sepsis endpoint, the other on decades of Russian clinical use that has rarely faced independent replication.
LL-37: a deep innate-immunity literature next to a failed Phase IIb primary endpoint
The only human cathelicidin has two decades of membrane-biology and immunology papers, a small 2014 venous-ulcer signal, and a 2021 multicentre trial that did not beat placebo in the full cohort. It is not an MHRA-authorised medicine.
AOD-9604 versus HGH fragment 176–191: related C-terminal fragments, unequal evidence
Vendor catalogues often treat the two names as synonyms. They are not. Only the tyrosine-stabilised analogue entered human obesity trials — and those trials did not meet a published primary efficacy endpoint.
Dihexa: an angiotensin-IV analogue whose HGF/c-Met mechanism papers were retracted
After the 2025 JPET retractions, the remaining Dihexa literature is a thin, mixed preclinical column — one independent APP/PS1 mouse study, one negative Huntington-model study, a 2013 characterisation that still carries an Expression of Concern, and no human trial.
5-Amino-1MQ: what the NNMT-inhibitor literature actually shows
5-Amino-1MQ is a methylquinolinium small molecule, not a peptide. A 2018 Biochemical Pharmacology paper reported reduced adiposity in diet-induced obese mice. There is no published human interventional trial, and the MHRA has not authorised the compound as a medicine.
Tesamorelin: indication-level visceral-adiposity evidence, still unlicensed in the UK
A GHRH analogue with completed Phase 3 programmes in HIV-associated excess visceral adipose tissue, later liver-fat trials, and no MHRA marketing authorisation. Overseas product licences do not create a UK medicine.
BPC-157: a deep preclinical column next to a nearly empty human one
Two 2025 orthopaedic reviews and a 2026 biopharmaceutical appraisal map the same gap: decades of rodent work, fewer than 30 documented human subjects, and no completed controlled trial. UK clinics making medicinal claims for the pentadecapeptide sit on the wrong side of the Human Medicines Regulations 2012.
NICE TA1152: semaglutide recommended to reduce major adverse cardiovascular events in adults with established CVD and BMI ≥27
Published 7 May 2026, TA1152 is the first NICE technology appraisal that positions a GLP-1 receptor agonist as a cardiovascular secondary-prevention option — defined by vascular disease and weight, not by glycaemia.
Retatrutide TRANSCEND-T2D-1 Phase 3 published in The Lancet: 1.94-point HbA1c reduction and 15.3% mean weight loss at 40 weeks
The first peer-reviewed Phase 3 type 2 diabetes trial of the GIP/GLP-1/glucagon triple agonist reports treatment-regimen results at 40 weeks. Retatrutide is not licensed in the UK.
MHRA identifies falsified Mounjaro (tirzepatide) 15 mg KwikPens in UK supply
A 24 February 2026 Drug Safety Update reports five falsified 15 mg pens, batch D873576, supplied through one Birmingham online pharmacy. Testing found tirzepatide in recovered devices, but the pens failed licensed quality and sterility standards.
MHRA authorises oral semaglutide (Wegovy tablet): first peptide GLP-1 tablet licensed for weight management in the UK
On 11 June 2026 the MHRA authorised Novo Nordisk’s once-daily tablet. It is a prescription-only medicine. A NICE appraisal for NHS use is still pending.
MHRA authorises orforglipron (Foundayo): UK first in Europe to license an oral non-peptide GLP-1 receptor agonist
On 10 August 2026 the MHRA authorised Eli Lilly’s once-daily tablet for weight management and type 2 diabetes. It is a prescription-only medicine. A NICE appraisal for NHS use is still pending.
Retatrutide TRIUMPH-2 and TRIUMPH-3 Phase 3: 20.8% and 22.6% mean weight loss at 80 weeks in type 2 diabetes and established cardiovascular disease
Eli Lilly reported topline results from two pivotal 80-week trials on 23 July 2026. The data are sponsor-disclosed and not yet peer-reviewed. Retatrutide is not licensed in the UK.
MOTS-c: what the mitochondrial-encoded peptide literature actually shows
A 16-residue peptide encoded by mitochondrial 12S rRNA has a coherent preclinical metabolic story. Human interventional evidence remains thin, and MOTS-c is not an MHRA-licensed medicine.
Ipamorelin: a selective ghrelin-receptor agonist with a narrow published human dataset
Novo Nordisk designed ipamorelin as a pentapeptide GH secretagogue with less ACTH and cortisol release than earlier GHRPs. Human evidence is largely pharmacokinetic and a negative postoperative-ileus programme. It is not MHRA-licensed.
Growth-hormone secretagogues compared: GHRH analogues versus ghrelin-receptor agonists
Sermorelin, CJC-1295 and tesamorelin act at the GHRH receptor. Ipamorelin, GHRP-2, GHRP-6 and hexarelin act at GHS-R1a. The two classes are not interchangeable, and only tesamorelin has a mature indication-level evidence base — not in the UK.
Mazdutide GLORY-1 Phase 3 published in NEJM: dual GLP-1/glucagon agonist reduces body weight in Chinese adults with overweight or obesity
Innovent and Lilly's once-weekly oxyntomodulin analogue met its primary endpoint in a 48-week placebo-controlled obesity trial. China has since authorised a pharmaceutical product. Mazdutide is not an MHRA-licensed medicine.
GLP-1 receptor agonists show strong cardiovascular protection: meta-analysis confirms tirzepatide and semaglutide reduce heart attacks, strokes and cardiovascular death
A 2025 meta-analysis adds to a growing body of evidence that GLP-1 receptor agonists — including tirzepatide and semaglutide — deliver significant cardiovascular benefits beyond weight loss and glycaemic control.
FDA approves oral semaglutide (Wegovy pill): first oral GLP-1 receptor agonist licensed for weight management
The US FDA has approved Novo Nordisk's oral semaglutide formulation of Wegovy, making it the first oral GLP-1 receptor agonist licensed for chronic weight management. The decision expands peptide-based obesity therapy beyond injectable delivery.
CagriSema REDEFINE-2 Phase 3: Novo Nordisk's dual amylin/GLP-1 combination shows superior weight loss in type 2 diabetes
Novo Nordisk reports that CagriSema (cagrilintide + semaglutide) achieved superior weight loss in adults with obesity or overweight and type 2 diabetes, building on the REDEFINE-1 obesity data.
Orforglipron ACHIEVE-3 and ACHIEVE-4 Phase 3: oral GLP-1 agonist demonstrates superior glycemic control in type 2 diabetes
Eli Lilly reports two successful Phase 3 trials showing orforglipron's potential as a foundational oral treatment for type 2 diabetes, strengthening its case beyond obesity.
FDA approves semaglutide for MASH liver disease: first GLP-1 agonist licensed for metabolic-associated steatohepatitis in the US
The FDA has approved semaglutide (Wegovy) for the treatment of metabolic-associated steatohepatitis (MASH), marking the first GLP-1 receptor agonist licensed for this serious liver condition.
Amgen reports positive topline results from first MariTide Phase 3 obesity trial
Maridebart cafraglutide (MariTide), Amgen's investigational monthly GIP receptor antagonist/GLP-1 receptor agonist, achieves positive topline results in its first Phase 3 obesity study — advancing the next generation of long-acting incretin therapeutics.
MHRA approves semaglutide (Wegovy) for metabolic-associated steatohepatitis (MASH): first GLP-1 agonist licensed for liver disease in the UK
The UK regulator has granted conditional approval for semaglutide to treat MASH in adults with moderate-to-advanced liver fibrosis — the first GLP-1 receptor agonist licensed for a liver disease indication in the UK.
MHRA strengthens warnings on acute pancreatitis risk with GLP-1 and dual GIP/GLP-1 receptor agonists
UK regulator updates drug safety guidance after reports of necrotising and fatal pancreatitis cases associated with GLP-1 receptor agonist therapies
MHRA reiterates GLP-1 receptor agonists are prescription-only medicines and targets improper supply channels
The UK regulator has reiterated that GLP-1 receptor agonists are prescription-only medicines and signalled enforcement against improper online supply — here is what it means for peptide researchers.
FDA proposes permanently excluding semaglutide, tirzepatide and liraglutide from 503B bulks list: compounding of GLP-1 peptides faces definitive end
The FDA's proposal to remove three major GLP-1 agonists from the 503B Bulks List would permanently end large-scale compounding of semaglutide, tirzepatide and liraglutide — here is what peptide researchers need to know.
Survodutide Phase 3: dual GLP-1/glucagon agonist cuts visceral fat by 34% and liver fat by 63%
Boehringer Ingelheim and Zealand Pharma's survodutide demonstrated 34% visceral fat reduction and 63% liver fat reduction in Phase 3 trials, strengthening the case for dual GLP-1/glucagon agonism in cardiometabolic disease.
FDA approves orforglipron (Foundayo): first oral GLP-1 agonist for obesity marks shift in peptide therapeutics
The FDA has approved orforglipron under the brand name Foundayo, making it the first oral GLP-1 receptor agonist approved for obesity. The approval transforms the peptide therapeutic landscape by eliminating the need for injections.
Retatrutide TRIUMPH-4 Phase 3: triple agonist delivers 26.5% weight loss and significant knee osteoarthritis pain relief
Eli Lilly's retatrutide achieved 26.5% mean weight loss and significantly reduced knee osteoarthritis pain in the Phase 3 TRIUMPH-4 trial, marking the first successful obesity drug trial to demonstrate concurrent osteoarthritis benefit.
Roche reports positive Phase II results for petrelintide in obesity: amylin analog advances to late-stage trials
Roche's amylin analog petrelintide shows promising weight loss in Phase II, positioning it alongside cagrilintide as next-generation amylin-based therapeutics move toward the clinic.
Ecnoglutide Phase 3 results published in The Lancet: biased GLP-1 receptor agonist shows significant weight loss in obesity trial
A multicentre randomised Phase 3 trial of ecnoglutide, published in The Lancet, demonstrates the potential of biased GLP-1 receptor agonism as a differentiated approach to obesity treatment.
VK2735 Phase 2 VENTURE trial: Viking Therapeutics' dual GIP/GLP-1 agonist shows up to 14.7% weight loss in 13-week study
The Phase 2 VENTURE trial of VK2735, a subcutaneous dual GIP/GLP-1 receptor agonist from Viking Therapeutics, demonstrated dose-dependent weight loss of up to 14.7% at 13 weeks in adults with obesity. Results were published in a peer-reviewed PubMed-indexed journal, adding to the growing body of evidence for next-generation multi-receptor agonists in obesity treatment.
NICE recommends tirzepatide (Mounjaro) for obesity on the NHS: what researchers need to know about TA1026
NICE TA1026: tirzepatide for obesity — eligibility, review points, and what this UK regulatory milestone means for peptide research.
MHRA warns of pulmonary aspiration risk with GLP-1 and dual GIP/GLP-1 receptor agonists before anaesthesia
UK regulator strengthens guidance on GLP-1 agonists and anaesthesia: what peptide researchers need to know about delayed gastric emptying and aspiration risk.
MHRA warns of very rare NAION risk with semaglutide: UK regulator adds vision-loss precautions to Wegovy, Ozempic and Rybelsus
The UK MHRA has published a Drug Safety Update warning that semaglutide may very rarely be associated with non-arteritic anterior ischaemic optic neuropathy (NAION), a condition that can cause sudden vision loss. The EMA's pharmacovigilance committee is also reviewing the signal.
FDA Pharmacy Compounding Advisory Committee to review BPC-157, TB-500 and thymosin peptides: what peptide researchers need to know
The US FDA's PCAC will evaluate whether BPC-157, TB-500, thymosin alpha-1 and other popular research peptides remain on the 503A bulk substances list — a decision that could reshape the global research peptide supply chain
FDA clarifies compounding policy as GLP-1 shortage formally resolves: what it means for peptide researchers
With the FDA declaring an end to the semaglutide and tirzepatide shortages, compounding pharmacies must cease production. The policy shift has ripple effects for the broader research peptide market.
FDA requests removal of suicidal ideation boxed warning from GLP-1 receptor agonists
After a multi-year review, the US FDA concluded there is no causal link between GLP-1 receptor agonists and suicidal thoughts or behaviours, and has asked manufacturers to remove the boxed warning.
Danuglipron Phase 2b results published: Pfizer's oral GLP-1 shows up to 12.9% weight loss but high discontinuation rates
Pfizer's oral small-molecule GLP-1 receptor agonist danuglipron demonstrated dose-dependent weight loss up to 12.9% in a Phase 2b trial, but nearly 38% of participants discontinued due to adverse events.
CagriSema REDEFINE-1 results: Novo Nordisk's dual amylin/GLP-1 combination achieves 22.7% weight loss in Phase 3
Novo Nordisk's CagriSema (cagrilintide + semaglutide) delivered a 22.7% mean weight reduction in the REDEFINE-1 Phase 3 trial, but fell short of expectations for superiority over semaglutide alone.
SURMOUNT-5: Tirzepatide outperforms semaglutide in first head-to-head obesity trial published in NEJM
Eli Lilly's dual GIP/GLP-1 agonist tirzepatide demonstrated superior weight loss compared to semaglutide in the landmark direct-comparison SURMOUNT-5 trial, results published in the New England Journal of Medicine.
Retatrutide Phase 3 TRIUMPH-1 results: Eli Lilly's triple-agonist delivers powerful weight loss in pivotal obesity trial
Eli Lilly has announced top-line results from the first pivotal Phase 3 trial of retatrutide, a GLP-1/GIP/glucagon triple agonist, in adults with obesity. The drug's mechanism — targeting three incretin pathways simultaneously — positions it as a potential next-generation therapy beyond tirzepatide.
MariTide Phase 2 obesity data presented at ADA 2025: monthly GIP/GLP-1 antagonist-agonist shows sustained weight loss
Amgen's MariTide (maridebart cafraglutide) demonstrated up to 20% weight loss at 52 weeks in a Phase 2 obesity trial, with a durable monthly dosing profile.
Pemvidutide Phase 2b MASH results published in The Lancet: dual GLP-1/glucagon agonist shows fibrosis improvement
The GLP-1/glucagon dual agonist pemvidutide met its primary endpoint in a Phase 2b trial for metabolic dysfunction-associated steatohepatitis, published in The Lancet.
Orforglipron Phase 3 ACHIEVE-1 results published in NEJM: oral GLP-1 agonist matches injectable weight loss
The first Phase 3 data for an oral GLP-1 receptor agonist show 12–15% weight loss at 36 weeks, positioning orforglipron as a potential tablet alternative to injectable semaglutide and tirzepatide.
MHRA tightens guidance on research-peptide labelling
New wording clarifies that "not for human consumption" must appear on the primary label, not just the certificate.