{"title":"Retatrutide","description":"\u003cp\u003eRetatrutide, development code LY3437943, is an investigational peptide that acts as an agonist at three receptors at once: the glucose-dependent insulinotropic polypeptide (GIP) receptor, the glucagon-like peptide-1 (GLP-1) receptor and the glucagon receptor. Phase 3 trials have reported since late 2025, but no country has yet approved it as a medicine, and its developer has said it intends to seek US approval in early 2027. This page lists every brand of retatrutide stocked at Free Muscle and compares them on form, pack size and batch testing, alongside what the published trials actually report.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eResearch use only.\u003c\/strong\u003e Retatrutide on this page is supplied for laboratory research use only, to adults aged 18 or over. It is not for human consumption, and this page gives no dosing, usage or treatment information of any kind. What follows describes the compound, what the published studies report and how to compare the listing we stock.\u003c\/p\u003e\n\n\u003ch2\u003eWhat is retatrutide?\u003c\/h2\u003e\n\u003cp\u003eRetatrutide was engineered by Eli Lilly as a single peptide based on the GIP sequence; in its first human study, a single-dose trial, its pharmacokinetic profile supported once-weekly administration (Coskun 2022). Its distinguishing feature is glucagon receptor activity on top of the GIP and GLP-1 agonism found in existing licensed medicines.\u003c\/p\u003e\n\u003cp\u003eIts status needs stating precisely. Retatrutide is an investigational medicine. Phase 2 trials in obesity and in type 2 diabetes were published in 2023, and the first Phase 3 papers followed in 2026, with further Phase 3 trials still running. It has no marketing authorisation from the MHRA, the EMA or the FDA, so it cannot be prescribed outside a clinical trial. It is not named individually on the WADA Prohibited List, but section S0 of the 2026 List bans at all times any substance not covered elsewhere on the List that has no current approval for human therapeutic use, including drugs in clinical development.\u003c\/p\u003e\n\u003ch2\u003eWhat the published research reports\u003c\/h2\u003e\n\u003cp\u003eThe Phase 2 obesity trial randomised 338 adults with obesity or overweight to once-weekly subcutaneous retatrutide at several dose levels or placebo for 48 weeks. Body weight fell in a dose-related way, by up to about 24 per cent at 48 weeks in the highest-dose group compared with about 2 per cent on placebo. The most common adverse events were gastrointestinal (nausea, diarrhoea, vomiting, constipation), they were dose-related, and heart rate rose in a dose-dependent way, peaking at 24 weeks (Jastreboff 2023). The parallel Phase 2 trial in 281 people with type 2 diabetes reported reductions in HbA1c and body weight versus placebo and versus dulaglutide over 36 weeks, again with gastrointestinal adverse events in about a third of retatrutide participants (Rosenstock 2023).\u003c\/p\u003e\n\u003cp\u003eIn the Phase 3 trial TRIUMPH-1 (2,339 participants with obesity, none with diabetes, 80 weeks), mean weight fell by 17.6, 23.7 and 25.0 per cent in the three retatrutide arms versus 3.9 per cent with placebo, with gastrointestinal events again the most common (Jastreboff 2026).\u003c\/p\u003e\n\u003cp\u003eTRIUMPH-2, in 1,152 people living with obesity and type 2 diabetes, found low blood pressure and dysaesthesia (abnormal skin sensation) more frequent than on placebo, and as many as 12 per cent in one retatrutide arm discontinued because of adverse events or death, compared with 5 per cent (Bellido 2026).\u003c\/p\u003e\n\u003cp\u003eTwo limitations dominate. Every trial used subcutaneous injection under clinical supervision with gradual dose escalation, and peptides of this size are largely broken down in the digestive tract, so nothing in the literature supports the idea that a capsule reproduces these results. And every trial was funded by the manufacturer, with the longest published follow-up at 80 weeks. None of the above is a claim about any product on this page.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eJastreboff AM, et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 Trial. N Engl J Med. 2023;389(6):514-526. PMID: 37366315.\u003c\/li\u003e\n\u003cli\u003eRosenstock J, et al. Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes: a randomised, double-blind, placebo and active-controlled, parallel-group, phase 2 trial conducted in the USA. Lancet. 2023;402(10401):529-544. PMID: 37385280.\u003c\/li\u003e\n\u003cli\u003eCoskun T, et al. LY3437943, a novel triple glucagon, GIP, and GLP-1 receptor agonist for glycemic control and weight loss: From discovery to clinical proof of concept. Cell Metab. 2022;34(9):1234-1247.e9. PMID: 35985340.\u003c\/li\u003e\n\u003cli\u003eJastreboff AM, et al. Retatrutide, a Triple Hormone Receptor Agonist, for Treatment of Obesity. N Engl J Med. 2026. Online ahead of print. PMID: 42814954.\u003c\/li\u003e\n\u003cli\u003eBellido V, et al. Retatrutide in adults with obesity and type 2 diabetes (TRIUMPH-2): a double-blind, parallel-group, randomised, placebo-controlled, phase 3 trial. Lancet. 2026. Online ahead of print. PMID: 42810372.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eBrands of retatrutide we stock\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003ca href=\"\/en-ro\/products\/retatrutide\"\u003eFree Muscle Retatrutide Research Peptide\u003c\/a\u003e. Free Muscle brand, sold as capsules. The listing text does not yet state the strength per capsule or the number of capsules, so request the batch certificate before making any comparison. Every Free Muscle batch is assayed by Janoshik Analytical, an independent laboratory, and the certificate of analysis for the batch you hold is sent by email on request.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eRetatrutide is currently stocked from Free Muscle only. If other brands are added they will be listed here with the same information so that the comparison stays consistent across the shop.\u003c\/p\u003e\n\u003ch3\u003eHow to compare them\u003c\/h3\u003e\n\u003cp\u003eWhere a strength per unit is stated, multiply it by the units in the pack to get total compound, and divide the price by that number for cost per milligram. With a peptide like this, check the form and route stated on the listing, because an injectable vial and a capsule are not interchangeable and the published trials used only one of them. Above all, ask for the batch certificate: for a compound this new, a certificate that confirms identity by mass spectrometry and states purity is the only evidence that the pack contains what the label says.\u003c\/p\u003e\n\u003ch2\u003eBatch testing and certificates of analysis\u003c\/h2\u003e\n\u003cp\u003eFor a peptide this new, the batch certificate matters most. Identity should be confirmed by LC-MS (liquid chromatography with mass spectrometry), showing the mass expected for retatrutide rather than that of another peptide; purity, usually by HPLC, shows what share of the material is intact molecule rather than fragments; and any quantity reported per capsule can be checked against the label. Every Free Muscle batch is assayed by Janoshik Analytical, an independent laboratory, and its certificate reaches you by email once you give us the batch number on your label.\u003c\/p\u003e\n\u003cp\u003eA document that lacks a batch number, a test date or the laboratory's name is not a batch record. Our \u003ca href=\"\/en-ro\/pages\/lab-tests\"\u003elab tests page\u003c\/a\u003e explains what to look for.\u003c\/p\u003e\n\u003ch2\u003eWhere to buy retatrutide in the UK: how to check a supplier\u003c\/h2\u003e\n\u003cp\u003eWhichever shop you buy retatrutide from, check these five points before you order:\u003c\/p\u003e\n\u003col\u003e\n\u003cli\u003e\n\u003cstrong\u003eA batch number and a certificate for that batch.\u003c\/strong\u003e The pack should carry a batch number, and the seller should be able to show a certificate of analysis for that same batch from a named laboratory, with the test date. Every Free Muscle-brand batch is assayed by Janoshik Analytical, and we send the certificate for your batch on request.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe strength per capsule and the capsule count.\u003c\/strong\u003e With both figures you can work out the total milligrams in the pack and the price per milligram. If a listing does not state one of them, ask the seller before you order.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eResearch-use labelling and an age check.\u003c\/strong\u003e A research compound should be sold for laboratory research use only, not for human consumption, to adults aged 18 or over, with no dosing or usage advice. That is how every listing here is sold.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrices in pounds sterling and tracked UK dispatch.\u003c\/strong\u003e UK delivery from us is free and tracked on every order, with no minimum spend, and usually arrives 2-3 working days after dispatch; orders placed before 2pm Monday to Friday are processed the same working day.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eA clear returns policy.\u003c\/strong\u003e Unopened items can be returned to us within 30 days.\u003c\/li\u003e\n\u003c\/ol\u003e\n\u003cp\u003eBrand on this page: \u003ca href=\"\/en-ro\/collections\/brand-free-muscle\"\u003eFree Muscle\u003c\/a\u003e. The \u003ca href=\"\/en-ro\/blogs\/news\/how-to-choose-a-sarms-supplier-uk-checklist\"\u003eUK supplier checklist\u003c\/a\u003e and \u003ca href=\"\/en-ro\/pages\/lab-tests\"\u003ehow we test\u003c\/a\u003e go into more detail.\u003c\/p\u003e\n\n\u003ch2\u003eLegal status in the UK\u003c\/h2\u003e\n\u003cp\u003eRetatrutide is not a licensed medicine in the UK and has no MHRA marketing authorisation, nor does it hold approval from the EMA or FDA. It is an investigational medicine available to patients only within clinical trials. It is not an authorised food supplement and may not be sold for human consumption. It is supplied here for laboratory research to adults aged 18 and over. It is not a controlled drug. Anyone seeking treatment for weight or blood glucose should speak to a doctor, since this is not a treatment and licensed options with clinical supervision exist. For background on how research peptides sit within UK law, see our \u003ca href=\"\/en-ro\/blogs\/news\/sarms-vs-peptides-choosing-by-goal\"\u003eSARMs versus peptides guide\u003c\/a\u003e.\u003c\/p\u003e\n\u003cp\u003eIn October 2025 the MHRA stated that retatrutide has not been approved for UK use and that, outside authorised clinical trials, any products sold in the UK claiming to contain it are likely to be illegal and potentially dangerous to health; in May 2026 it made arrests at a site producing unlicensed weight-loss medicines, retatrutide among them. Lilly, the developer, states that retatrutide is legally available only to participants in its clinical trials.\u003c\/p\u003e\n\u003ch2\u003eStorage and handling\u003c\/h2\u003e\n\u003cp\u003ePeptides degrade faster with heat, moisture and light, so keep the container sealed in a cool, dry, dark place, labelled with its batch number and out of reach of children and animals. The \u003ca href=\"\/en-ro\/products\/retatrutide\"\u003eproduct page\u003c\/a\u003e names the ways peptides degrade and covers handling and disposal.\u003c\/p\u003e\n\u003ch2\u003eDelivery and returns\u003c\/h2\u003e\n\u003cp\u003eFree Muscle is the trading name of FreeMuscle, a business registered in Andorra, with UK operations and dispatch in Scunthorpe. UK shipping costs nothing, is tracked and comes in plain packaging, and weekday orders that arrive before 2pm are processed on the day; EU delivery takes three to seven working days. Anything unopened can come back within 30 days, and only adults aged 18 or over may order. Terms are on our \u003ca href=\"\/en-ro\/pages\/shipping\"\u003eshipping\u003c\/a\u003e and \u003ca href=\"\/en-ro\/pages\/guarantee\"\u003eguarantee\u003c\/a\u003e pages.\u003c\/p\u003e\n\u003ch2\u003eRelated reading\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"\/en-ro\/blogs\/news\/retatrutide-uk-licensing-status-trials-2026\"\u003eRetatrutide in the UK 2026: licensing status and trials\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-ro\/blogs\/news\/slu-pp-332-and-5-amino-1mq-research-guide\"\u003eSLU-PP-332 and 5-Amino-1MQ: what the mouse data show\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-ro\/blogs\/news\/how-to-choose-a-sarms-supplier-uk-checklist\"\u003eHow to choose a SARMs or peptide supplier in the UK: a checklist\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-ro\/blogs\/news\/do-oral-peptides-work\"\u003eDo oral peptides actually work? The honest answer\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-ro\/blogs\/news\/what-is-janoshik-analytical\"\u003eWhat is Janoshik Analytical? Third-party testing explained\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-ro\/blogs\/news\/how-to-read-a-certificate-of-analysis\"\u003eHow to read a certificate of analysis\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"\/en-ro\/collections\/weight-loss\"\u003eMetabolic support\u003c\/a\u003e, \u003ca href=\"\/en-ro\/collections\/peptides\"\u003eall peptides\u003c\/a\u003e and \u003ca href=\"\/en-ro\/collections\/5-amino-1mq\"\u003e5-Amino-1MQ\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cem\u003eResearch compounds sold by Free Muscle are supplied for laboratory research use only and are not for human consumption. They are not authorised as medicines by the MHRA, EMA or FDA, are not food supplements, and are sold only to adults aged 18 or over. Nothing on this page is medical or dosing advice.\u003c\/em\u003e\u003c\/p\u003e","products":[{"product_id":"retatrutide","title":"Retatrutide — Research Peptide","description":"\u003cp\u003e\u003cstrong\u003eRetatrutide (LY3437943), research peptide.\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eRetatrutide is an investigational triple agonist at the GIP, GLP-1 and glucagon receptors. \u003cstrong\u003eIt is not approved as a medicine by any regulator in the world\u003c\/strong\u003e, not the MHRA, not the EMA, not the FDA. Phase 2 obesity results were published in 2023; Phase 3 trials are still running. Nothing is finished.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eThe published trials used subcutaneous injection. This product is a capsule\u003c\/strong\u003e, and peptides taken by mouth are largely broken down in the gut. We are not going to claim an oral capsule reproduces trial results.\u003c\/p\u003e\u003cp\u003eTrial participants reported nausea, vomiting, diarrhoea and constipation, with dose escalation managed by clinicians throughout.\u003c\/p\u003e\u003cp\u003eWeight-management treatment is a matter for a doctor. There are licensed medicines with approved safety profiles and clinical supervision. This is not one of them and we are not selling it as one.\u003c\/p\u003e\u003cp\u003eIdentity and purity are verified per batch by Janoshik Analytical, an independent laboratory.\u003c\/p\u003e\u003cp\u003e\u003csmall\u003eResearch compounds sold by Free Muscle are supplied for laboratory research use only and are not for human consumption. They are not authorised as medicines by the MHRA, EMA or FDA, are not food supplements, and are sold only to adults aged 18 or over. Nothing on this page is medical or dosing advice.\u003c\/small\u003e\u003c\/p\u003e","brand":"FreeMuscle","offers":[{"title":"Default Title","offer_id":47171527639266,"sku":"28876573","price":89.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0772\/3499\/5426\/files\/IMG-2901.jpg?v=1766262736"}],"url":"https:\/\/freemuscle.co.uk\/en-ro\/collections\/retatrutide.oembed","provider":"Free Muscle","version":"1.0","type":"link"}