SR9009 (Stenabolic)
1 product from 1 brand · free UK delivery · EU 3–7 days
SR9009, sold under the name Stenabolic and sometimes written SR-9009, is a synthetic small-molecule agonist of the nuclear receptors Rev-Erbα and Rev-Erbβ, which sit at the heart of the circadian clock and regulate genes for lipid and glucose metabolism. It is not a SARM, has never been tested in humans and is not an approved medicine anywhere. This page lists every brand of SR9009 stocked at Free Muscle, compared on strength per capsule, capsules per pack and batch testing.
What is SR9009?
SR9009 was designed at the Scripps Research Institute in Florida as a research tool for studying Rev-Erb, together with a sister compound, SR9011. Rev-Erb proteins are transcriptional repressors: when activated they switch off target genes, including core clock genes and genes involved in fat storage, gluconeogenesis and inflammation. In mice, activating Rev-Erb altered circadian behaviour and raised energy expenditure, which is the origin of the reputation the compound later acquired in the fitness market.
Two facts limit that reputation. First, the animal work used injection, and pharmacokinetic studies report that SR9009 has very poor oral bioavailability and is rapidly metabolised, which makes the capsule form sold everywhere questionable on pharmacology alone. Second, a 2019 study using mice with both Rev-Erb genes deleted found that SR9009 still changed cell viability and metabolism, so some of its effects are not mediated by Rev-Erb at all and its true mechanism is unresolved. There are no human trials, no human safety data and no regulatory approval. SR9009 is named on the WADA Prohibited List under S4, hormone and metabolic modulators, and is prohibited at all times.
What the published research reports
The 2012 Nature paper that introduced SR9009 reported that injected SR9009 altered circadian gene expression in mice, increased energy expenditure and reduced fat mass and plasma lipids in diet-induced obese mice, without changing food intake (Solt 2012). A 2013 study in Nature Medicine reported that Rev-Erbα regulates mitochondrial content in skeletal muscle and that injected SR9009 increased running endurance in mice, alongside greater mitochondrial biogenesis (Woldt 2013). A 2016 in vitro study of SR9009 and SR9011 metabolism, carried out for anti-doping purposes, characterised the metabolites produced by liver enzymes so that laboratories could detect the compound in athletes (Geldof 2016). Then in 2019 a group at the University of Pennsylvania showed that SR9009 decreased cell viability and rewired metabolism in hepatocytes and embryonic stem cells that lacked both Rev-Erbα and Rev-Erbβ, concluding that its effects cannot be used as a proxy for Rev-Erb activity (Dierickx 2019). Every efficacy result is from injected mice or cultured cells. None of the above is a claim about any product on this page.
- Solt LA, et al. Regulation of circadian behaviour and metabolism by synthetic REV-ERB agonists. Nature. 2012;485(7396):62-68. PMID: 22460951.
- Woldt E, et al. Rev-erb-α modulates skeletal muscle oxidative capacity by regulating mitochondrial biogenesis and autophagy. Nat Med. 2013;19(8):1039-1046. PMID: 23852339.
- Geldof L, et al. In Vitro Metabolic Studies of REV-ERB Agonists SR9009 and SR9011. Int J Mol Sci. 2016;17(10):1676. PMID: 27706103.
- Dierickx P, et al. SR9009 has REV-ERB-independent effects on cell proliferation and metabolism. Proc Natl Acad Sci U S A. 2019;116(25):12147-12152. PMID: 31127047.
Brands of SR9009 we stock
- iMuscle Stenabolic SR-9009, 10mg, 60 capsules. iMuscle brand, capsule form, 10mg per capsule, 60 capsules, 600mg in the pack. A manufacturer certificate of analysis is shown where iMuscle supplies one for the batch we hold; we leave the field blank where it does not.
There is currently no Free Muscle-brand SR9009, so no listing on this page carries a Janoshik Analytical certificate. As further brands are added they will appear here with the same information: strength, count, form and batch documentation.
How to compare them
Strength per capsule multiplied by capsules per pack gives total compound: 60 capsules at 10mg is 600mg. Divide the price by that figure for cost per milligram. When a second brand is listed, compare on that number and on whether a batch-specific certificate exists, not on the label design or the name on the tub. The Stenabolic name is a marketing term and tells you nothing about what is in the capsule.
Batch testing and certificates of analysis
A certificate of analysis (COA) is a laboratory report tied to one manufactured batch. It records the identity of the compound tested (usually by HPLC or LC-MS against a reference standard) and the purity found, and it carries the batch number, the test date and the name of the laboratory that ran the assay. Every Free Muscle-brand batch is assayed by Janoshik Analytical, an independent laboratory, and we will send the certificate for the batch you hold if you email us with the batch number from the label. For iMuscle, the only brand on this page, a COA is shown only where the manufacturer has supplied one for the specific batch we hold, and we leave the field blank rather than imply a test that does not exist.
A generic PDF with no batch number, no date or no named laboratory is not a batch certificate, whatever it is called. Match the batch number on the certificate to the number on your pack before relying on it. Our lab tests page explains what to look for.
Legal status in the UK
SR9009 is not a licensed medicine in the UK and has no MHRA marketing authorisation. It is not an authorised food supplement and may not be sold for human consumption. It is supplied for laboratory research to adults aged 18 and over. It is not a controlled drug under the Misuse of Drugs Act. In sport it is prohibited at all times under WADA class S4, hormone and metabolic modulators, where SR9009 is named as an example. For context on how research compounds are treated in UK law, see our SARMs research guide.
Storage and handling
Keep the container sealed, in a cool, dry place away from direct light, and return it there each time the container has been opened. Do not decant into unlabelled containers. Keep out of the reach of children and animals. Handle in line with ordinary laboratory good practice, with gloves and a clean work surface, and dispose of unwanted material through an appropriate waste route rather than down the sink.
Delivery and returns
Free Muscle is a UK company (FreeMuscle LTD, Scunthorpe). Every order ships with free tracked UK delivery in plain packaging with nothing on the outside to say what is inside. Orders placed before 2pm Monday to Friday are processed the same working day. EU delivery takes three to seven working days. Unopened items can be returned within 30 days. Customers must be 18 or over. Full details are on our shipping page and our guarantee page.
Related reading
- What are SARMs? The 2026 research guide
- SARMs vs peptides: choosing by goal
- Price per milligram: the only honest way to compare
- How to read a certificate of analysis
- Cardarine (GW-501516), SLU-PP-332, metabolic support and all SARMs
SR9009 (Stenabolic) is supplied for laboratory research use only. It is not a licensed medicine, not a food supplement and not for human consumption. Nothing on this page has been evaluated by the MHRA, EMA or FDA, and nothing on this page is medical, health or dosing advice. Sales are restricted to adults aged 18 and over.
Frequently asked questions
Is SR9009 legal in the UK?
SR9009 is legal to buy and hold for research purposes in the UK and is not a controlled drug. It is not, however, a licensed medicine or an authorised food supplement, so it cannot lawfully be sold for people to consume. Free Muscle supplies it for laboratory research to adults aged 18 and over only. Under the WADA Prohibited List it is named under S4 and banned in sport at all times.
Is SR9009 a SARM?
No. SR9009 is a Rev-Erb agonist, acting on nuclear receptors that form part of the circadian clock. A SARM by definition binds the androgen receptor, and SR9009 has no affinity for it. It is sold in the same shops and to the same buyers, which is why the confusion persists, but it belongs to a different pharmacological class.
Has SR9009 been tested in humans?
No. There are no human clinical trials of SR9009, no human safety data and no regulatory approval anywhere. Everything published about its effects comes from injected mice and cultured cells, and a 2019 study found that some of those effects occur even in cells with no Rev-Erb receptors, so the mechanism itself is unresolved.
What is the difference between SR9009 and Cardarine?
They are unrelated molecules that happen to share a market. Cardarine is a PPARδ agonist with a small amount of short-term human trial data and a rodent carcinogenicity history that halted development. SR9009 is a Rev-Erb agonist with no human data at all. Both are WADA-prohibited under S4.
Does SR9009 work orally?
Published pharmacokinetic work reports very poor oral bioavailability and rapid metabolism for SR9009, and the animal studies that produced its reputation used injection. Whether a capsule delivers anything meaningful is an open question that the literature does not answer, and we make no claim about it.
Is SR9009 detectable in sport drug tests?
Yes. Anti-doping researchers have characterised the metabolites of SR9009 and SR9011 specifically so that laboratories can detect them, and the compound is named on the WADA Prohibited List. A routine urine test is expected to find it, so a competing athlete should treat it as a certain sanction rather than a gamble.
How do I verify the batch of SR9009 I receive?
The SR9009 currently listed is made by iMuscle. A certificate of analysis is shown on the product page only where iMuscle supplies one for the batch we hold; otherwise the field is blank. Check that the batch number on any certificate matches the number printed on your pack before relying on it.
Which SR9009 strength should I choose?
There is only one SR9009 listing at present, the iMuscle 10mg, 60-capsule pack, so no choice arises, and we would not make a recommendation if it did. SR9009 is supplied for laboratory research and nothing here is guidance on selection or use. The factual figure for the listing is 600mg of compound per pack, which is the number to use for any cost-per-milligram comparison when other brands appear.