{"title":"YK-11","description":"\u003cp\u003eYK-11, also written YK11 and sold under names such as Myostine, is a synthetic steroid (CAS 1370003-76-1) first described by researchers at Toho University in Japan in 2011 as a partial agonist of the androgen receptor. It is often sold as a SARM and described as a myostatin inhibitor. This page lists every brand of YK-11 stocked at Free Muscle, compared on strength per capsule, capsules per pack and batch testing, and summarises what the published research does and does not show.\u003c\/p\u003e\n\u003ch2\u003eWhat is YK-11?\u003c\/h2\u003e\n\u003cp\u003eUnlike RAD-140, LGD-4033 or ostarine, YK-11 is built on a steroid skeleton: it is a 19-norpregnane derivative related to nandrolone, carrying an unusual orthoester group on its D-ring. In reporter-gene assays it activated the androgen receptor (AR) only partially, accelerated AR movement into the nucleus, and did so without inducing the amino\/carboxyl-terminal (N\/C) interaction that full agonists such as dihydrotestosterone rely on. Because it produced gene-selective effects, the Toho group suggested it might function as a SARM despite its steroidal structure.\u003c\/p\u003e\n\u003cp\u003eThe myostatin claim began with a cell-culture finding. In mouse C2C12 myoblasts, YK-11 induced expression of follistatin, an endogenous antagonist of myostatin, and the myogenic differentiation it caused was reversed by an anti-follistatin antibody (2013). A 2021 study in septic mice also described YK-11 as a myostatin inhibitor, but no study in people has tested the idea, so for humans it remains a hypothesis. YK-11 has no pharmaceutical developer, was never entered into clinical trials, and has never been approved as a medicine by the MHRA, EMA, FDA or any other regulator. Anti-doping scientists have characterised it from a seized black-market product.\u003c\/p\u003e\n\u003cp\u003eIdentity, as recorded in PubChem:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCAS number\u003c\/strong\u003e: 1370003-76-1\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMolecular formula\u003c\/strong\u003e: C25H34O6\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMolecular weight\u003c\/strong\u003e: 430.5\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePubChem CID\u003c\/strong\u003e: 119058028\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eChemical name\u003c\/strong\u003e: (17alpha,20E)-17,20-[(1-methoxyethylidene)bis(oxy)]-3-oxo-19-norpregna-4,20-diene-21-carboxylic acid methyl ester\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eWhat the published research reports\u003c\/h2\u003e\n\u003cp\u003eThe evidence is preclinical: cell studies, rodent studies and doping-control chemistry. Nobody has published a human trial of YK-11, and none was registered on ClinicalTrials.gov when we checked on 2 October 2026.\u003c\/p\u003e\n\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eStudy\u003c\/th\u003e\n\u003cth\u003eModel\u003c\/th\u003e\n\u003cth\u003eWhat was reported\u003c\/th\u003e\n\u003cth\u003eLimits\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eKanno 2011\u003c\/td\u003e\n\u003ctd\u003eAndrogen-response-element luciferase assay; MDA-MB 453 cells\u003c\/td\u003e\n\u003ctd\u003ePartial agonist of the AR that accelerated its nuclear translocation without inducing the N\/C interaction, and blocked DHT from inducing it; effects on gene expression varied by gene\u003c\/td\u003e\n\u003ctd\u003eCells only\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eKanno 2013\u003c\/td\u003e\n\u003ctd\u003eC2C12 mouse myoblasts\u003c\/td\u003e\n\u003ctd\u003eStronger induction of MyoD, Myf5 and myogenin than DHT; induced follistatin, and an anti-follistatin antibody reversed the differentiation\u003c\/td\u003e\n\u003ctd\u003eCells only; the source of the myostatin label\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eYatsu 2018\u003c\/td\u003e\n\u003ctd\u003eMC3T3-E1 mouse osteoblasts\u003c\/td\u003e\n\u003ctd\u003eFaster proliferation and mineralisation, more osteoprotegerin and osteocalcin and raised phosphorylated Akt, all attenuated by an AR antagonist\u003c\/td\u003e\n\u003ctd\u003eCells only\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePiper 2018\u003c\/td\u003e\n\u003ctd\u003eYK-11 identified in a seized black-market product; elimination study with deuterium-labelled YK-11\u003c\/td\u003e\n\u003ctd\u003e14 metabolites found in urine, none of them intact YK-11; glucuronide and sulfate conjugates still detectable beyond 48 hours; two adopted for routine anabolic-agent screening\u003c\/td\u003e\n\u003ctd\u003eDesigned for doping control, not to measure effects\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLee 2021\u003c\/td\u003e\n\u003ctd\u003eMice with gram-negative sepsis\u003c\/td\u003e\n\u003ctd\u003eMyostatin and follistatin rose in septic muscle; YK-11, described as a myostatin inhibitor, brought down inflammatory cytokines and markers of organ damage and cut deaths from sepsis\u003c\/td\u003e\n\u003ctd\u003eMouse infection model only\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDahleh 2023\u003c\/td\u003e\n\u003ctd\u003eMale Wistar rats, five weeks, with or without swimming exercise\u003c\/td\u003e\n\u003ctd\u003eMore oxidative stress and poorer mitochondrial function in the hippocampus; swimming blocked part of the mitochondrial damage, but not the oxidative stress\u003c\/td\u003e\n\u003ctd\u003eRats only\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDahleh 2024\u003c\/td\u003e\n\u003ctd\u003eRats, five weeks, with or without swimming exercise\u003c\/td\u003e\n\u003ctd\u003eLower hippocampal BDNF\/TrkB\/CREB signalling, higher IL-1beta and IL-6, lower IL-10, raised p38 MAPK activity and activation of the Bax\/Bcl-2\/caspase-3 apoptotic cascade, with impaired aversive memory consolidation; exercise offset some changes\u003c\/td\u003e\n\u003ctd\u003eRats only\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSobolevsky 2024\u003c\/td\u003e\n\u003ctd\u003eDoping control sample\u003c\/td\u003e\n\u003ctd\u003eThe UCLA Olympic Analytical Laboratory reported detecting YK-11 in a doping control sample\u003c\/td\u003e\n\u003ctd\u003eA detection report, not an effect study\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWang 2025\u003c\/td\u003e\n\u003ctd\u003eBone-marrow mesenchymal stem cells; rats with skull defects\u003c\/td\u003e\n\u003ctd\u003ePromoted bone-forming differentiation and, as a YK-11-loaded hydrogel, repair of skull defects; both effects were suppressed when the AR was inhibited\u003c\/td\u003e\n\u003ctd\u003eLocal application in rats; the proposed BMP2\/Smad pathway is not established in people\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003eThese findings describe cell lines, laboratory animals and doping-control samples. None of them is a claim about the products listed on this page.\u003c\/p\u003e\n\u003ch2\u003eBrands of YK-11 we stock\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFree Muscle YK-11, 10mg, 60 capsules.\u003c\/strong\u003e Our own brand, capsule form, 600mg of compound per pack. Every batch is assayed by Janoshik Analytical and the certificate for your batch is available by email on request. \u003ca href=\"\/en-ro\/products\/yk-11-10mg\"\u003eView the Free Muscle YK-11 listing\u003c\/a\u003e.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eiMuscle YK-11, 10mg, 60 capsules.\u003c\/strong\u003e Capsule form, 600mg per pack. A certificate of analysis is shown on the listing only where iMuscle has supplied one for the batch we hold. \u003ca href=\"\/en-ro\/products\/imuscle-yk-11-60-10mg\"\u003eView the iMuscle YK-11 listing\u003c\/a\u003e.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eHow to compare them\u003c\/h3\u003e\n\u003cp\u003eBoth listings hold 600mg per pack (10mg multiplied by 60 capsules), and the comparison table above gives the price per milligram for each, so the real difference is testing. The Free Muscle batch has a Janoshik identity and purity assay for its lot number; for the iMuscle batch, it depends on whether the manufacturer has provided a certificate. Because YK-11 has turned up in seized black-market material analysed by doping scientists, independent confirmation of identity matters more here than for most compounds. Our guide to \u003ca href=\"\/en-ro\/blogs\/news\/price-per-mg-compare-sarms-peptides\"\u003eprice per milligram\u003c\/a\u003e covers the arithmetic.\u003c\/p\u003e\n\u003ch2\u003eBatch testing and certificates of analysis\u003c\/h2\u003e\n\u003cp\u003eYK-11 is harder to certify than most compounds sold as SARMs. Mass spectrometry can confirm a match with its formula, C25H34O6, and molecular weight, 430.5, and the PubChem InChIKey, KCQHQCDHFVGNMK-PQUNLUOYSA-N, encodes the full structure for comparison. A purity percentage on its own, however, does not show that the geometry at each stereocentre and at the E double bond is as described. The Cologne doping-control group also called the orthoester-derived group on its D-ring arguably labile, so unexpected extra peaks in a chromatogram may be breakdown products rather than random impurities.\u003c\/p\u003e\n\u003cp\u003eJanoshik Analytical, an independent laboratory, assays every Free Muscle batch of YK-11, and its certificate is emailed on request with the batch number from the label. The iMuscle listing carries a certificate only when iMuscle has sent us one covering the batch in our stock. A document with no lot number or test date is not a batch certificate. Our \u003ca href=\"\/en-ro\/pages\/lab-tests\"\u003elab tests page\u003c\/a\u003e walks through matching a certificate to its batch.\u003c\/p\u003e\n\u003ch2\u003eWhere to buy YK-11 in the UK: how to check a supplier\u003c\/h2\u003e\n\u003cp\u003eWhichever shop you buy YK-11 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. For iMuscle, a certificate is shown where the brand supplies one for the batch we hold.\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; the comparison table above does this for every listing here that states both. 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\u003eBrands on this page: \u003ca href=\"\/en-ro\/collections\/brand-free-muscle\"\u003eFree Muscle\u003c\/a\u003e and \u003ca href=\"\/en-ro\/collections\/brand-imuscle\"\u003eiMuscle\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\u003eYK-11 is not named in the Misuse of Drugs Act 1971, although the Act also defines some anabolic steroids by chemical structure rather than by name. It has no MHRA marketing authorisation and cannot be sold as a medicine, and the Food Standards Agency, according to UK Anti-Doping, regards SARMs as unauthorised novel foods, which keeps them out of food and dietary supplements. Free Muscle sells YK-11 for laboratory research alone, to customers who are 18 or older.\u003c\/p\u003e\n\u003cp\u003eYK-11 is one of the SARMs given as examples in S1.2, other anabolic agents, of the 2026 WADA Prohibited List, so it is banned in and out of competition, and UK Anti-Doping lists it as YK-11 (Myostine). For the wider class, see our \u003ca href=\"\/en-ro\/blogs\/news\/what-are-sarms-the-2026-research-guide\"\u003eresearch guide to SARMs\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch2\u003eStorage and handling\u003c\/h2\u003e\n\u003cp\u003eOrthoester groups as a class are split by water, particularly under acidic conditions, and the one in YK-11 has been described as arguably labile, so keep the capsules dry: sealed in the original, batch-numbered bottle in a cool, dark place, with any desiccant left in, away from children and pets, and handle it with ordinary laboratory good practice. Fuller notes on condensation, signs of degradation and disposal are on the \u003ca href=\"\/en-ro\/products\/yk-11-10mg\"\u003eFree Muscle YK-11 page\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch2\u003eDelivery and returns\u003c\/h2\u003e\n\u003cp\u003eAll orders are sent from our UK operations in Scunthorpe, with free tracked UK delivery and plain packaging. Place an order before 2pm Monday to Friday and it is processed that working day; EU orders take 3 to 7 working days to arrive. Unopened items may be returned within 30 days. Customers must be 18 or over. Our \u003ca href=\"\/en-ro\/pages\/shipping\"\u003eshipping page\u003c\/a\u003e and \u003ca href=\"\/en-ro\/pages\/guarantee\"\u003eguarantee page\u003c\/a\u003e have the full terms.\u003c\/p\u003e\n\u003ch2\u003eRelated reading\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"\/en-ro\/blogs\/news\/what-are-sarms-the-2026-research-guide\"\u003eWhat are SARMs? The 2026 research guide\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-ro\/blogs\/news\/sarms-explained-how-selective-androgen-receptor-modulators-work-1135-86\"\u003eSARMs explained: how selective androgen receptor modulators work\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\u003ca href=\"\/en-ro\/blogs\/news\/what-is-janoshik-analytical\"\u003eWhat is Janoshik Analytical?\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 supplier in the UK: a checklist\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eRelated collections: \u003ca href=\"\/en-ro\/collections\/rad-140\"\u003eRAD-140 (Testolone)\u003c\/a\u003e, \u003ca href=\"\/en-ro\/collections\/mk-677\"\u003eMK-677 (Ibutamoren)\u003c\/a\u003e, \u003ca href=\"\/en-ro\/collections\/lgd-4033\"\u003eLGD-4033 (Ligandrol)\u003c\/a\u003e, \u003ca href=\"\/en-ro\/collections\/sarms\"\u003eall SARMs\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch2\u003eReferences\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eKanno Y, et al. (17alpha,20E)-17,20-[(1-methoxyethylidene)bis(oxy)]-3-oxo-19-norpregna-4,20-diene-21-carboxylic acid methyl ester (YK11) is a partial agonist of the androgen receptor. Biol Pharm Bull. 2011;34(3):318-323. PMID: 21372378.\u003c\/li\u003e\n\u003cli\u003eKanno Y, et al. Selective androgen receptor modulator, YK11, regulates myogenic differentiation of C2C12 myoblasts by follistatin expression. Biol Pharm Bull. 2013;36(9):1460-1465. PMID: 23995658.\u003c\/li\u003e\n\u003cli\u003eYatsu T, et al. Selective Androgen Receptor Modulator, YK11, Up-Regulates Osteoblastic Proliferation and Differentiation in MC3T3-E1 Cells. Biol Pharm Bull. 2018;41(3):394-398. PMID: 29491216.\u003c\/li\u003e\n\u003cli\u003ePiper T, et al. Studies on the in vivo metabolism of the SARM YK11: Identification and characterization of metabolites potentially useful for doping controls. Drug Test Anal. 2018;10(11-12):1646-1656. PMID: 30379415.\u003c\/li\u003e\n\u003cli\u003eLee SJ, et al. Myostatin inhibitor YK11 as a preventative health supplement for bacterial sepsis. Biochem Biophys Res Commun. 2021;543:1-7. PMID: 33588136.\u003c\/li\u003e\n\u003cli\u003eDahleh MMM, et al. YK11 induces oxidative stress and mitochondrial dysfunction in hippocampus: The interplay between a selective androgen receptor modulator (SARM) and exercise. J Steroid Biochem Mol Biol. 2023;233:106364. PMID: 37468001.\u003c\/li\u003e\n\u003cli\u003eDahleh MMM, et al. From gains to gaps? How Selective Androgen Receptor Modulator (SARM) YK11 impact hippocampal function: In silico, in vivo, and ex vivo perspectives. Chem Biol Interact. 2024;394:110971. PMID: 38521455.\u003c\/li\u003e\n\u003cli\u003eSobolevsky T, et al. Detection of selective androgen receptor modulator YK-11 in a doping control sample. Drug Test Anal. 2024;16(6):655-660. PMID: 37946705.\u003c\/li\u003e\n\u003cli\u003eWang R, et al. YK11 promotes osteogenic differentiation of BMSCs and repair of bone defects. J Mol Endocrinol. 2025;74(2):e240073. PMID: 39660819.\u003c\/li\u003e\n\u003cli\u003eUK Anti-Doping. SARMs (supplement ingredient warning). Last updated 29 April 2026.\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. Summaries of published research describe study findings and are not claims about any product.\u003c\/em\u003e\u003c\/p\u003e","products":[{"product_id":"yk-11-10mg","title":"YK-11 — Myostatin Inhibitor · 10mg · 60 Capsules","description":"\u003cp\u003e\u003cstrong\u003eYK-11, 10mg × 60 capsules.\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYK-11 is structurally a steroid, not a true SARM, although it is usually sold alongside them. It is sometimes described as a myostatin-pathway agent; that description rests largely on a single cell-culture study and there is no human data.\u003c\/p\u003e\u003cp\u003eBecause it has a steroidal backbone, androgenic and liver effects cannot be ruled out. It is \u003cstrong\u003enot authorised for human consumption in the UK or EU\u003c\/strong\u003e and is prohibited in sport by WADA.\u003c\/p\u003e\u003cp\u003eIdentity and purity are verified per batch by Janoshik Analytical, an independent laboratory. Certificate of Analysis available on request. We do not publish dosing schedules, cycle lengths or post-cycle protocols for human use.\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":46857393144034,"sku":"10000012","price":49.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0772\/3499\/5426\/files\/yk_11_10mg_60_capsules.jpg?v=1766262356"},{"product_id":"christmas-bulking-bundle","title":"Research Bundle — MK-677 + RAD-140 + YK-11","description":"\u003cp\u003e\u003cstrong\u003eThree bottles, 180 capsules: MK-677, RAD-140 and YK-11.\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eMK-677 is a ghrelin-receptor secretagogue, RAD-140 is a SARM, and YK-11 is a steroidal compound. Only MK-677 has published human trial data; the other two do not.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy buy the bundle? Price, and nothing else.\u003c\/strong\u003e It is the same three products at a lower total than buying them separately. We are not claiming they work better together.\u003c\/p\u003e\u003cp\u003eBuying compounds together does not make them safer; each carries its own risks, set out on its own page. \u003cstrong\u003eNone of the three is authorised for human consumption in the UK or EU\u003c\/strong\u003e, and all three are on the WADA Prohibited List.\u003c\/p\u003e\u003cp\u003eEvery batch is assayed by Janoshik Analytical, an independent laboratory. Certificates of Analysis available on request.\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":46920043462882,"sku":"BUNDLE-XMAS-001","price":100.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0772\/3499\/5426\/files\/IMG-1809.jpg?v=1766262497"},{"product_id":"imuscle-yk-11-60-10mg","title":"iMuscle YK-11 — 60 caps, 10mg","description":"\u003cp\u003eiMuscle YK-11 is supplied as 60 capsules stated at 10 mg each, giving 600 mg of YK-11 per pack. YK-11 is a steroidal partial agonist of the androgen receptor that is commonly sold alongside SARMs and is described in cell studies as a follistatin inducer. iMuscle manufactures it and Free Muscle stocks it in the Muscle Market range for laboratory research by adults only.\u003c\/p\u003e\n\u003ch2\u003eThis listing\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eCompound: YK-11\u003c\/li\u003e\n\u003cli\u003eBrand: iMuscle\u003c\/li\u003e\n\u003cli\u003eForm: capsules\u003c\/li\u003e\n\u003cli\u003ePack size: 60 capsules\u003c\/li\u003e\n\u003cli\u003eStated strength: 10 mg per capsule (manufacturer's label claim)\u003c\/li\u003e\n\u003cli\u003eStated total per pack: 600 mg\u003c\/li\u003e\n\u003cli\u003eIntended use: laboratory research only, not for human consumption\u003c\/li\u003e\n\u003cli\u003eSold to adults aged 18 and over\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eThe strength is the manufacturer's label claim; only a batch certificate confirms it. To compare brands of YK-11, use total milligrams per pack: dividing the listed price by the 600 mg stated here gives the cost per stated milligram, as explained in \u003ca href=\"\/en-ro\/blogs\/news\/price-per-mg-compare-sarms-peptides\"\u003eprice per milligram\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch2\u003eAbout YK-11\u003c\/h2\u003e\n\u003cp\u003eYK-11 is often grouped with SARMs, but it is a steroidal molecule: a 19-nor-pregnane derivative with a methyl ester side chain. It was described in 2011 by a group at Toho University in Japan, who showed in cell assays that it acts as a partial agonist at the androgen receptor, activating the receptor less fully than DHT (Kanno 2011).\u003c\/p\u003e\n\u003cp\u003eThe claim that YK-11 is a myostatin inhibitor comes from a 2013 study in C2C12 mouse myoblast cells, in which YK-11 increased expression of follistatin, a protein that binds myostatin, and promoted myogenic differentiation more than DHT did in that model (Kanno 2013). Both papers are cell-culture work. No human clinical trial of YK-11 has been published, so its pharmacokinetics, hormonal effects and liver tolerance in people are unknown.\u003c\/p\u003e\n\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eIdentifier\u003c\/th\u003e\n\u003cth\u003eYK-11\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eCAS number\u003c\/td\u003e\n\u003ctd\u003e1370003-76-1\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMolecular formula\u003c\/td\u003e\n\u003ctd\u003eC25H34O6\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMolecular weight\u003c\/td\u003e\n\u003ctd\u003e430.5 g\/mol\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInChIKey\u003c\/td\u003e\n\u003ctd\u003eKCQHQCDHFVGNMK-PQUNLUOYSA-N\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePubChem CID\u003c\/td\u003e\n\u003ctd\u003e119058028\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch3\u003eAnimal and metabolism studies\u003c\/h3\u003e\n\u003cp\u003eWork in living animals is recent and sparse, and much of the published in vivo work concerns metabolism for doping control (Piper 2018). One study followed rats for five weeks, with and without swimming exercise, to look for unwanted effects in the brain (Dahleh 2024). Animals given YK-11 retained an aversive memory task less well, showed weaker BDNF signalling in the hippocampus, had a cytokine balance tilted towards inflammation and showed activation of proteins that drive programmed cell death. Exercise offset part of this. One rat study cannot say what happens in people, but its findings point towards harm rather than benefit.\u003c\/p\u003e\n\u003cp\u003eThe cell and animal findings summarised here are not claims about this product.\u003c\/p\u003e\n\u003ch2\u003eYK-11 in the UK: buying, legal status and what to check\u003c\/h2\u003e\n\u003cp\u003eYK-11 is not a licensed medicine in the UK, and it has never been licensed in any other country: it has no MHRA marketing authorisation, is not an authorised food supplement, and cannot lawfully be sold for human consumption. Free Muscle supplies it to adults aged 18 or over for laboratory research only. Because it is a synthetic steroid, its status under the Misuse of Drugs Act is less clear-cut than that of non-steroidal SARMs, and buyers should take their own advice. It is prohibited at all times in sport, as the detection section below explains. Buyers are responsible for the rules that apply to them, including any anti-doping code. Background on the class is in \u003ca href=\"\/en-ro\/blogs\/news\/what-are-sarms-the-2026-research-guide\"\u003eWhat are SARMs? The 2026 research guide\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch3\u003eWhat a trustworthy UK listing shows\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eThe compound named precisely, ideally with its CAS number, not a nickname.\u003c\/li\u003e\n\u003cli\u003eA stated strength per capsule and a capsule count, so total content can be worked out.\u003c\/li\u003e\n\u003cli\u003eA batch number on the pack, and a certificate of analysis carrying that number from a named laboratory.\u003c\/li\u003e\n\u003cli\u003eA plain statement when no certificate exists for the batch in stock, instead of a generic PDF.\u003c\/li\u003e\n\u003cli\u003eA named seller, an 18+ restriction, plain packaging and tracked delivery.\u003c\/li\u003e\n\u003cli\u003eNo instructions for human use and no outcome promises.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eHow this listing measures up\u003c\/h3\u003e\n\u003cp\u003eThe 10 mg and 60-capsule figures are iMuscle's label claim, not a figure we have assayed. A certificate is shown only where iMuscle supplies one for the batch we hold, and we tell you when there is none. Testing is the real difference from Free Muscle's own-brand \u003ca href=\"\/en-ro\/products\/yk-11-10mg\"\u003eYK-11 10 mg\u003c\/a\u003e, which carries the same label strength and capsule count but is assayed batch by batch at Janoshik Analytical. Orders ship from FreeMuscle's UK operations in Scunthorpe by free tracked UK delivery in plain packaging; orders placed before 2pm Monday to Friday are processed the same working day, EU delivery takes 3 to 7 working days, and unopened items can be returned within 30 days (\u003ca href=\"\/en-ro\/pages\/shipping\"\u003edelivery\u003c\/a\u003e, \u003ca href=\"\/en-ro\/pages\/guarantee\"\u003ereturns\u003c\/a\u003e). Our \u003ca href=\"\/en-ro\/blogs\/news\/how-to-choose-a-sarms-supplier-uk-checklist\"\u003eUK supplier checklist\u003c\/a\u003e covers each test in more detail.\u003c\/p\u003e\n\u003ch2\u003eCapsules compared with other forms\u003c\/h2\u003e\n\u003cp\u003eYK-11 is offered as capsules, as solutions in dropper bottles and as loose powder, and injectable versions are widely searched for. No study has compared these forms and none has been evaluated in a clinical trial, so the differences below concern what can be measured and kept stable, not effect. This listing is capsules.\u003c\/p\u003e\n\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eForm\u003c\/th\u003e\n\u003cth\u003eWhat fixes the amount per unit\u003c\/th\u003e\n\u003cth\u003eWhat a certificate can confirm\u003c\/th\u003e\n\u003cth\u003eMain stability concern\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eCapsule\u003c\/td\u003e\n\u003ctd\u003eFill weight set at manufacture\u003c\/td\u003e\n\u003ctd\u003eContent per capsule and purity, if finished capsules are tested\u003c\/td\u003e\n\u003ctd\u003eHumidity once the container is opened\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSolution\u003c\/td\u003e\n\u003ctd\u003eConcentration, and whether the compound stays evenly dissolved\u003c\/td\u003e\n\u003ctd\u003eConcentration per millilitre on the test date\u003c\/td\u003e\n\u003ctd\u003eConstant contact with solvent\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePowder\u003c\/td\u003e\n\u003ctd\u003eWeighing by the researcher\u003c\/td\u003e\n\u003ctd\u003ePurity of the bulk material\u003c\/td\u003e\n\u003ctd\u003eHumidity and handling losses\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInjectable\u003c\/td\u003e\n\u003ctd\u003eConcentration, carrier and sterility\u003c\/td\u003e\n\u003ctd\u003eUsually concentration only; sterility needs separate testing\u003c\/td\u003e\n\u003ctd\u003eNo published characterisation for YK-11\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003eTwo points follow from the chemistry. First, the Cologne anti-doping group described the orthoester-derived group on the D-ring of YK-11 as arguably labile and found no unchanged YK-11 in urine after administration (Piper 2018). Groups that break down readily in the body are also exposed to hydrolysis in a solution containing water or acid, one reason a dry fill is the easier form to store and assay. Second, YK-11 is not a peptide but a small steroid, so the argument that peptides are largely digested when swallowed, discussed in \u003ca href=\"\/en-ro\/blogs\/news\/do-oral-peptides-work\"\u003eDo oral peptides actually work?\u003c\/a\u003e, does not apply. That is a point about chemistry, not a claim about what a capsule does. Fill accuracy is itself a manufacturing variable, which is why the certificate section below asks whether finished capsules or raw powder were tested.\u003c\/p\u003e\n\u003ch2\u003eYK-11 compared with RAD-140\u003c\/h2\u003e\n\u003cp\u003eRAD-140 (testolone) is the compound most often set beside YK-11, and iMuscle sells both in the same format: \u003ca href=\"\/en-ro\/products\/imuscle-testolon-rad-140-60-10mg\"\u003eiMuscle Testolone RAD-140\u003c\/a\u003e is also labelled 10 mg per capsule, 60 capsules. Identical label arithmetic hides two different molecules with very different evidence bases.\u003c\/p\u003e\n\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003ePoint\u003c\/th\u003e\n\u003cth\u003eYK-11\u003c\/th\u003e\n\u003cth\u003eRAD-140\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eChemical class\u003c\/td\u003e\n\u003ctd\u003eSteroid, 19-nor-pregnane derivative\u003c\/td\u003e\n\u003ctd\u003eNon-steroidal SARM\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFormula and molecular weight\u003c\/td\u003e\n\u003ctd\u003eC25H34O6, 430.5\u003c\/td\u003e\n\u003ctd\u003eC20H16ClN5O2, 393.8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOrigin\u003c\/td\u003e\n\u003ctd\u003eAcademic group, Toho University, 2011\u003c\/td\u003e\n\u003ctd\u003ePharmaceutical programme, Radius Health\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAction at the androgen receptor\u003c\/td\u003e\n\u003ctd\u003ePartial agonist in cell assays; induced follistatin in mouse muscle cells\u003c\/td\u003e\n\u003ctd\u003eAgonist designed for tissue selectivity, characterised in rats and monkeys\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePublished human data\u003c\/td\u003e\n\u003ctd\u003eNo clinical trial\u003c\/td\u003e\n\u003ctd\u003eOne phase 1 study in 22 women with advanced breast cancer\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMain adverse findings\u003c\/td\u003e\n\u003ctd\u003eMemory, inflammatory and cell-death changes in rat hippocampus\u003c\/td\u003e\n\u003ctd\u003eRaised liver enzymes, the most frequent adverse events in the phase 1 study\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eUK status\u003c\/td\u003e\n\u003ctd\u003eNot a licensed medicine; steroid structure makes its drugs-law status less clear-cut\u003c\/td\u003e\n\u003ctd\u003eNot a licensed medicine; research use only\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWADA\u003c\/td\u003e\n\u003ctd\u003eSection S1, prohibited at all times\u003c\/td\u003e\n\u003ctd\u003eSection S1, prohibited at all times\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003eThe evidence gap is the main difference. RAD-140's human data come from one oncology study in patients with advanced disease (LoRusso 2022), yet that study still produced a measured half-life and a documented liver-enzyme signal. YK-11 has neither, so any statement about how it behaves in people rests on nothing published. The regulatory picture differs for a structural reason: a steroid backbone brings YK-11 closer to the anabolic steroids that UK drugs law already controls, whereas RAD-140 is chemically unrelated to them. Neither compound is approved anywhere, both are banned in sport, and nothing here ranks one above the other for any purpose. Brands of RAD-140 are compared on the \u003ca href=\"\/en-ro\/collections\/rad-140\"\u003eRAD-140 collection page\u003c\/a\u003e, and its research is summarised in \u003ca href=\"\/en-ro\/blogs\/news\/rad-140-testolone-what-the-research-says\"\u003eRAD-140 (Testolone): what the research says\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch2\u003eReading the certificate of analysis for this product\u003c\/h2\u003e\n\u003cp\u003eiMuscle is a third-party brand, so any certificate of analysis is the manufacturer's, not ours. Where iMuscle supplies a COA for the batch we hold, we show it or send it by email on request; where none exists for the batch in stock, we say so rather than show a generic document. Free Muscle-brand compounds are assayed batch by batch at Janoshik Analytical; that programme does not cover iMuscle. When an iMuscle certificate is available, these are the fields to check.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBatch or lot number\u003c\/strong\u003e: the same number as the one printed on your pack.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIdentity\u003c\/strong\u003e: the method (HPLC against a YK-11 reference standard, LC-MS, or both) and a result consistent with C25H34O6, molecular weight 430.5. YK-11 has a defined E geometry at its side-chain double bond, and an isomer would share its mass, so a retention-time match to a reference standard is stronger evidence than mass alone.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePurity\u003c\/strong\u003e: the main peak as a percentage of everything the HPLC detected. The remainder may be synthesis by-products or breakdown products.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eContent per capsule\u003c\/strong\u003e: the milligrams found in finished capsules, to set against the stated 10 mg; a raw-powder result is not the same measurement.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest date and laboratory\u003c\/strong\u003e: when and by whom the analysis was run.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eFor this brand, a missing field has a specific meaning. With no certificate for the batch in stock, nothing independent confirms identity, purity or content, and the 10 mg figure stays a label claim. Without a content figure, a certificate confirms what the material is but not the fill; without a batch number, it cannot be tied to your pack; without a named laboratory, it cannot be checked with the lab that issued it. Email us through the \u003ca href=\"\/en-ro\/pages\/contact\"\u003econtact page\u003c\/a\u003e with the product name and the batch number on your pack and we will tell you what we hold. See \u003ca href=\"\/en-ro\/pages\/lab-tests\"\u003elab tests\u003c\/a\u003e and \u003ca href=\"\/en-ro\/blogs\/news\/how-to-read-a-certificate-of-analysis\"\u003ehow to read a COA\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch2\u003eDetection, sport and testing\u003c\/h2\u003e\n\u003cp\u003eYK-11 is prohibited at all times, in and out of competition, under section S1 (anabolic agents) of the WADA Prohibited List, which UK Anti-Doping applies in the UK. Under the strict liability principle of the anti-doping code, an athlete is responsible for any prohibited substance found in their sample, whatever the product label said.\u003c\/p\u003e\n\u003cp\u003eLaboratories can find it. In an elimination study with deuterium-labelled YK-11, the Cologne anti-doping laboratory identified fourteen urinary metabolites and no unchanged YK-11 in urine. Unconjugated metabolites had gone within 24 hours, while glucuronide and sulfate conjugates were still traceable after more than 48 hours, and two glucuronidated metabolites were added to the laboratory's routine screen for anabolic agents (Piper 2018). The study itself was prompted by the detection of YK-11 in a seized black-market product.\u003c\/p\u003e\n\u003cp\u003eThose timings describe how long metabolites were traced in one study; they are not a detection window. With no published human pharmacokinetic study, there is no established half-life for YK-11 in people and the full window is unknown. The reliable statement is that YK-11 is detectable.\u003c\/p\u003e\n\u003ch2\u003eStorage, stability and handling\u003c\/h2\u003e\n\u003cp\u003eNo stability study of YK-11 capsules has been published, so storage practice rests on general chemistry and the manufacturer's label. Water can cleave the ester and orthoester-derived groups in the molecule, and heat and light degrade most organic research materials.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eKeep the capsules in the original closed container, cool, dry and away from direct sunlight and heat.\u003c\/li\u003e\n\u003cli\u003eClose the lid promptly and leave any desiccant sachet in place; humidity is the main avoidable threat.\u003c\/li\u003e\n\u003cli\u003eKeep the label intact: the batch number links the capsules to any certificate and to any quality query.\u003c\/li\u003e\n\u003cli\u003eRecord the date of receipt and any printed expiry date; without one, a certificate's test date is the only dated reference.\u003c\/li\u003e\n\u003cli\u003eSoft, sticky, discoloured or clumped capsules suggest moisture damage; note the batch number and contact us.\u003c\/li\u003e\n\u003cli\u003eKeep out of reach of children and pets, handle with gloves in a clean area free of food and drink, and dispose of unwanted material under local chemical-waste rules.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eIf you might return the item, leave it sealed: returns are accepted within 30 days on unopened items only.\u003c\/p\u003e\n\u003ch2\u003eGlossary\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePartial agonist\u003c\/strong\u003e: a ligand whose maximum effect at a receptor stays below that of a reference hormone; for YK-11 in cell assays the reference was DHT.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDHT (dihydrotestosterone)\u003c\/strong\u003e: a potent androgen made from testosterone in tissues such as skin and prostate.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e19-nor steroid\u003c\/strong\u003e: a steroid missing the carbon atom usually found at position 19, the skeleton YK-11 shares with nandrolone.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFollistatin\u003c\/strong\u003e: a glycoprotein that captures myostatin and activin outside the cell; the 2013 C2C12 study reported a rise in its expression, the basis of the myostatin-inhibitor label.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eC2C12 cells\u003c\/strong\u003e: a mouse muscle precursor line that fuses into muscle-like fibres in culture.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHydrolysis\u003c\/strong\u003e: cleavage of a chemical bond by water, the main storage risk for the ester and orthoester-derived groups in YK-11.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLabel claim\u003c\/strong\u003e: the amount a manufacturer prints per capsule, here 10 mg, unconfirmed until a content assay is run.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRetention time\u003c\/strong\u003e: how long a compound takes to pass through an HPLC column, compared against a reference standard to support identity.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConjugated metabolite\u003c\/strong\u003e: a breakdown product linked to glucuronic acid or sulfate for excretion; these were the longest-traced YK-11 markers in the Cologne study.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eAbout iMuscle YK-11\u003c\/h2\u003e\u003cp\u003eThe YK-11 pot from iMuscle has a red label with YK 11 in the centre and the iMUSCLE mark on its black panel above. Its front box states 60 capsules, 10 mg each; the side panel gives 10 mg of YK 11 per capsule, the compound's systematic name as a methyl ester, and iMuscle's line claiming purity tested above 97%. The brand's Romanian site lists the pot as YK 11, \"60\/10mg\".\u003c\/p\u003e\u003cp\u003eiMuscle's About page explains its testing policy in its own terms: because SARMs are unregulated and raw material need not meet any standard, it says it tests all lots at an independent European laboratory; the quality page adds a 97% purity minimum for raw material. Those are the brand's statements. YK-11 also features in two iMuscle stacks we list, \u003ca href=\"\/en-ro\/products\/imuscle-testolon-yk11-ibutamoren\"\u003eTestolon, YK-11 and Ibutamoren\u003c\/a\u003e and \u003ca href=\"\/en-ro\/products\/imuscle-ligandrol-testolon-yk-11\"\u003eLigandrol, Testolon and YK-11\u003c\/a\u003e; the rest of the range is on the \u003ca href=\"\/en-ro\/collections\/brand-imuscle\"\u003eiMuscle brand page\u003c\/a\u003e.\u003c\/p\u003e\u003cp\u003eUnlike the SARMs it is sold beside, YK-11 has a steroid skeleton. Its literature is mostly cell work published since 2011, with a few rat studies, and it has never been tested in people; its steroid structure leaves its UK legal position less settled than that of the non-steroidal SARMs, and WADA bans it under S1. Free Muscle also sells a 10 mg, 60-capsule YK-11 under its own brand, with each batch assayed at Janoshik Analytical; both appear on the \u003ca href=\"\/en-ro\/collections\/yk-11\"\u003eYK-11 collection\u003c\/a\u003e.\u003c\/p\u003e\u003cp\u003eThe gallery shows protocol RN18695 from 2021, which has no lot number, alongside an HPLC print-out for YK11 with lot 20210911. Neither is tied to the pots in stock now. Check your pot for a lot or batch code and, if one is printed, \u003ca href=\"\/en-ro\/pages\/contact\"\u003esend it to us\u003c\/a\u003e; we will pass on any certificate iMuscle provides for that lot, or tell you plainly that there is none.\u003c\/p\u003e\u003ch2\u003eRelated\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003ca href=\"\/en-ro\/collections\/yk-11\"\u003eAll brands of YK-11\u003c\/a\u003e, compared on strength, pack size and batch testing\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"\/en-ro\/collections\/brand-imuscle\"\u003eAll iMuscle products\u003c\/a\u003e stocked at Free Muscle\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-ro\/blogs\/news\/yk-11-what-is-known\"\u003eYK-11: a steroidal compound sold as a SARM, what is actually known\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"\/en-ro\/collections\/rad-140\"\u003eRAD-140 (testolone)\u003c\/a\u003e and the full \u003ca href=\"\/en-ro\/collections\/sarms\"\u003eSARMs range\u003c\/a\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"\/en-ro\/pages\/shipping\"\u003eDelivery\u003c\/a\u003e and \u003ca href=\"\/en-ro\/pages\/guarantee\"\u003ereturns\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\n\u003ch2\u003eReferences\u003c\/h2\u003e\n\u003col\u003e\n\u003cli\u003eKanno Y, et al. (17alpha,20E)-17,20-[(1-methoxyethylidene)bis(oxy)]-3-oxo-19-norpregna-4,20-diene-21-carboxylic acid methyl ester (YK11) is a partial agonist of the androgen receptor. Biol Pharm Bull. 2011;34(3):318-23. \u003ca href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/21372378\/\" rel=\"noopener\"\u003ePMID: 21372378\u003c\/a\u003e.\u003c\/li\u003e\n\u003cli\u003eKanno Y, et al. Selective androgen receptor modulator, YK11, regulates myogenic differentiation of C2C12 myoblasts by follistatin expression. Biol Pharm Bull. 2013;36(9):1460-5. \u003ca href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/23995658\/\" rel=\"noopener\"\u003ePMID: 23995658\u003c\/a\u003e.\u003c\/li\u003e\n\u003cli\u003ePiper T, et al. Studies on the in vivo metabolism of the SARM YK11: Identification and characterization of metabolites potentially useful for doping controls. Drug Test Anal. 2018;10(11-12):1646-56. \u003ca href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/30379415\/\" rel=\"noopener\"\u003ePMID: 30379415\u003c\/a\u003e.\u003c\/li\u003e\n\u003cli\u003eDahleh MMM, et al. From gains to gaps? How Selective Androgen Receptor Modulator (SARM) YK11 impact hippocampal function: In silico, in vivo, and ex vivo perspectives. Chem Biol Interact. 2024;394:110971. \u003ca href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/38521455\/\" rel=\"noopener\"\u003ePMID: 38521455\u003c\/a\u003e.\u003c\/li\u003e\n\u003cli\u003eLoRusso P, et al. A First-in-Human Phase 1 Study of a Novel Selective Androgen Receptor Modulator (SARM), RAD140, in ER+\/HER2- Metastatic Breast Cancer. Clin Breast Cancer. 2022;22(1):67-77. \u003ca href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/34565686\/\" rel=\"noopener\"\u003ePMID: 34565686\u003c\/a\u003e.\u003c\/li\u003e\n\u003c\/ol\u003e","brand":"iMuscle","offers":[{"title":"Default Title","offer_id":48468980400354,"sku":null,"price":42.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0772\/3499\/5426\/files\/YK11_720x_d356e17a-105c-480a-834b-d0c2826f4875.jpg?v=1789931421"}],"url":"https:\/\/freemuscle.co.uk\/en-ro\/collections\/yk-11.oembed","provider":"Free Muscle","version":"1.0","type":"link"}