Contents12 sections
SR9009, sold as Stenabolic, is a lab-made compound that switches on REV-ERB, a pair of proteins that help run the body’s internal clock and its handling of fat and sugar. In mice it raised energy expenditure, cut fat mass and let the animals run further. That is where its reputation as a fat-loss and endurance compound comes from.
The catch is that almost none of this has been shown in people. SR9009 has never been tested in a human clinical trial, the mice in the key studies received it by injection, and the compound is reported to be poorly absorbed when swallowed, which is how nearly everyone who buys it takes it. It is also not a SARM, even though it is sold alongside them.
This guide covers what the research found, the oral bioavailability problem, user reports, commonly reported doses, side effects, legal status, and how SR9009 compares with Cardarine, Ostarine and Andarine. Nothing here is a recommendation to use it.
Key Takeaways
- SR9009 (Stenabolic) is a REV-ERB agonist developed at Scripps Research. It is not a SARM or a steroid and does not act on the androgen receptor.
- Its fat-loss, blood-lipid and endurance effects were seen in mice given injections. No human trial has tested it for anything.
- SR9009 is reported to have poor oral bioavailability, so capsules and liquids taken by mouth may deliver little active drug. No human absorption data exist.
- It is not proven safe. It acts on the body clock, reduced deep and REM sleep in mice, has off-target effects in cell studies, and its effects in people are unknown.
- Commonly reported use is 20-30mg a day, split across the day, for 4-8 weeks. These figures come from user practice, not research.
What Is SR9009 (Stenabolic)?
SR9009 is a synthetic compound developed at the Scripps Research Institute in the lab of Thomas Burris. It was first described in a 2012 paper in Nature, together with a sister compound, SR9011, as one of the first drug-like molecules able to activate the REV-ERB receptors. “Stenabolic” is a vendor name for the same molecule. For the basic profile, see our Stenabolic compound page.
It is often sold as a SARM, but it isn’t one. SARMs bind the androgen receptor, the receptor testosterone acts on. SR9009 doesn’t. It is not a steroid either. That matters for both its effects and its risks: it is not a muscle builder in the way SARMs are, and it doesn’t work through the testosterone system.
How SR9009 Works
REV-ERBα and REV-ERBβ are nuclear receptors: proteins inside the cell that switch genes on and off. They are part of the core circadian clock. They hold back BMAL1, one of the clock’s main driver genes, and they help set the daily rhythm of fat, sugar and cholesterol handling in the liver, muscle and fat tissue. The body’s own activator for them is heme.
SR9009 binds these receptors and increases their activity, which is meant to shift metabolism toward burning more energy and storing less fat. Because the same receptors run the body clock, it also changes sleep and daily activity patterns.
What the Research Shows (and What It Doesn’t)
Everything known about SR9009’s effects comes from mice and from cells grown in the lab. These are the main findings.
Fat Loss and Blood Lipids in Mice
In the 2012 Nature study, SR9009 changed the daily rhythm of clock and metabolism genes in the liver, muscle and fat tissue of mice, and it changed the animals’ daily activity pattern, a direct sign that it acts on the body clock. Treated mice used more oxygen, a marker of higher energy expenditure. Mice made obese on a high-fat diet lost weight, mainly fat mass, and their blood lipids and blood sugar improved. The compound was given by injection.
Endurance and Muscle Mitochondria in Mice
A 2013 study in Nature Medicine found that REV-ERBα helps control how many mitochondria, the energy-producing parts of the cell, skeletal muscle makes. Mice given SR9009 had more mitochondria in their muscle and could run further. Scripps announced these mouse results in 2013, and this is the study behind SR9009’s reputation as an endurance compound. No study has shown the same effect in people.
Sleep and Anxiety-Like Behaviour in Mice
In a 2014 mouse study from the same group, REV-ERB agonists from this series increased time spent awake and reduced deep (slow-wave) and REM sleep. The mice also showed less anxiety-like behaviour. The first finding is the opposite of the “better sleep” claim found on many SR9009 pages: in the only research available, sleep went down.
Effects That Bypass REV-ERB
A 2019 study in PNAS tested SR9009 on cells engineered to lack both REV-ERB receptors. SR9009 still reduced cell growth and changed cell metabolism and gene activity. In other words, some of what it does has nothing to do with its intended target. Effects seen in earlier studies can’t all be credited to REV-ERB, and its off-target actions are poorly understood.
Cancer Cell Research
A 2018 Nature study found that SR9009 and SR9011 killed several types of cancer cells in culture while sparing normal cells, and slowed the growth of glioblastoma, an aggressive brain tumour, in mice. This is early lab research, and strong effects on cell survival are a reason for caution, not a reason to take it.
Human Data
There are no published clinical trials of SR9009 in people: no dose-finding study, no safety study and no study of how the body absorbs and clears it. Claims that it raises human metabolism by 50%, strips a set percentage of body fat, or has “no known side effects” have no human research behind them.
| Common Claim | What the Evidence Shows |
|---|---|
| Boosts metabolism and fat loss | Seen in obese mice given injections (animal data); never tested in humans |
| Increases endurance | Mice had more muscle mitochondria and ran further (animal data); never tested in humans |
| Improves sleep | In mice, REV-ERB agonists from this series reduced deep and REM sleep |
| Keeps muscle on a cut | No human study; it does not act on the androgen receptor |
| Safe, no side effects | No human safety data exist |
| Works just as well by mouth | Reported to be poorly absorbed orally; the key mouse studies used injection |
The Oral Bioavailability Problem
Oral bioavailability is the share of a swallowed dose that reaches the bloodstream intact. The mouse studies that built SR9009’s reputation gave it by injection, and the compound is reported to have poor oral bioavailability and a short duration of action. This is the gap most SR9009 marketing skips.
Almost all SR9009 sold online is meant to be swallowed, as capsules or liquids. No study has measured how much of an oral dose reaches the blood in people. The mice also received doses per kilogram of body weight far above the 20-30mg a day users commonly report. Put together, there is no evidence that a typical oral dose produces a meaningful level of active drug in the body.
The common workarounds don’t solve this:
- Splitting the dose: the “5mg every few hours” routine rests on a short half-life figure that has never been measured in people. Taking a poorly absorbed compound more often doesn’t make it better absorbed.
- Sublingual and transdermal versions: products made to be held under the tongue or applied to the skin claim better absorption, but no published data show that they deliver more drug.
There is also the question of what is actually in the bottle. When researchers analysed 44 products sold online as SARMs (published in JAMA in 2017), only about half contained a SARM at all, many labels did not match the contents, and a few products contained no active compound. Products sold as SR9009 come from the same unregulated research-chemical market.
SR9009 Results: What Users Report
Online reports of SR9009 results are mixed. Some users describe more energy and endurance during cardio or faster fat loss while dieting; many notice nothing.
These reports are hard to read. Most come from people who are also dieting, doing more cardio, using stimulants or running other compounds. Expectation alone can make training feel easier. And given the absorption problem and product quality, many users may not be getting much SR9009 at all.
The old claim of losing about 5% of body weight over 8 weeks has no study behind it. A calorie deficit and regular cardio can produce that on their own. Realistically, there is no reliable evidence that oral SR9009 adds anything beyond diet and training, and no data on what it does to people over time.
Commonly Reported Doses and Cycle Length
There is no studied human dose of SR9009, so there is no dose anyone can call effective or safe. The figures below are what users commonly report, not advice.
| Item | Commonly Reported | What Is Known |
|---|---|---|
| Daily amount | 20-30mg a day | No human dose-finding study exists |
| Timing | Split into several doses across the day | Based on a short half-life never measured in people |
| Cycle length | 4-8 weeks | No human data for any duration |
| Time off | At least as long as the cycle | A forum convention, not a research finding |
Does SR9009 Need PCT?
Post-cycle therapy (PCT) is used to restart natural testosterone production after compounds that suppress it. SR9009 doesn’t act on the androgen receptor or the testosterone system, so it isn’t expected to cause the suppression SARMs do. That is a prediction from how it works, not a finding from human blood work.
The old advice that SR9009 stacks with Ostarine or LGD-4033 need no PCT is wrong. Those compounds are SARMs, and SARMs studied in people lower natural testosterone. Any suppression in such a stack comes from the SARM, not from SR9009. Our guide to PCT for SARMs covers what the evidence shows on suppression and recovery.
SR9009 Side Effects and Unknown Risks
With no human trials, nobody knows SR9009’s side effect profile. “No known side effects” really means no one has studied them. This is what can be said:
- No human safety data: no study has looked at its effects on the liver, kidneys, heart, blood lipids or hormones in people, short or long term.
- Body-clock disruption: REV-ERB is part of the circadian clock. In mice, REV-ERB agonists reduced deep and REM sleep and changed daily activity rhythms. Poor sleep works against fat loss, recovery and training.
- Off-target effects: cell studies show SR9009 changes cell growth and metabolism even without its target receptors. What those effects mean in people is unknown.
- Liver and metabolism: REV-ERB helps control fat, sugar and cholesterol handling in the liver. Changing that system without monitoring is an unknown, not a benefit.
- Product quality: research-chemical products are unregulated, and mislabelling is documented across the wider SARMs market.
- User-reported complaints: forum reports mention stomach upset and trouble sleeping. These are anecdotal and unverified.
The old claim that SR9009 can’t harm the liver because it isn’t a steroid doesn’t hold up: liver safety has to be tested, and it hasn’t been.
Is SR9009 Legal?
SR9009 is not approved by the FDA or any other regulator for any medical use. In the US it is sold as a research chemical labelled “not for human consumption”, which is why vendors make no bodybuilding claims for it. Rules on research compounds differ by country.
In sport, SR9009 is named on the World Anti-Doping Agency (WADA) Prohibited List under hormone and metabolic modulators, the same class that includes Cardarine. Substances in this class are banned at all times, in and out of competition.
SR9009 vs Cardarine, Ostarine and Andarine
These compounds are sold side by side, but they have different targets and very different amounts of evidence.
| Compound | Target | Human Data | Taken by Mouth | Main Concern |
|---|---|---|---|---|
| SR9009 (Stenabolic) | REV-ERB (body-clock receptors) | None | Reported poor oral bioavailability | No human safety data; less deep and REM sleep in mice |
| Cardarine (GW501516) | PPAR-delta | Small early-stage trials | Yes, developed as an oral drug | Development stopped after cancers in rodent studies |
| Ostarine (MK-2866) | Androgen receptor (SARM) | Several clinical trials | Yes | Testosterone suppression, lower HDL, liver injury case reports |
| Andarine (S4) | Androgen receptor (SARM) | Very limited | Yes | Vision changes reported; development stopped |
SR9009 vs Cardarine
Both are marketed for endurance and fat loss, and WADA bans both in the same class. Cardarine (GW501516) activates PPAR-delta, a different receptor that shifts muscle toward burning fat. Unlike SR9009, it was developed as an oral drug and reached early human trials for blood lipids, where it raised HDL cholesterol and lowered triglycerides. Development was stopped after rodent studies found cancers in multiple organs, and WADA issued a rare public warning about it in 2013.
So Cardarine has some human data and works by mouth, but carries a cancer signal from animal studies; SR9009 has neither human data nor a proven oral route. Neither has been shown to be safe (see Cardarine side effects and cancer risk). Claims that one beats the other for energy, sleep or anxiety are forum opinion, not research.
Overview
- Form: Oral Capsules
- Researched Dosage: 10 mg to 20 mg daily (1-2 capsules)
- Typical Cycle: 6-8 weeks
- Cost: $69.95
- Stacking Options: LGD-4033, MK-677, Ostarine (MK-2866)
Pros
- Human studies from its time as a drug candidate found higher HDL (“good”) cholesterol and lower triglycerides. This is why it was first studied for heart disease risk.
- Long half-life of about 16-24 hours means one capsule a day is usually enough to keep steady levels.
- Pre-dosed capsules remove the measuring step, so they’re easy to take consistently and to travel with.
Cons
- Animal studies found it caused cancer at multiple sites, and no one knows whether a safe human dose exists over the long term.
- Can be detected in drug tests long after the last dose, and WADA has warned athletes about it specifically.
SR9009 vs Ostarine
Ostarine (enobosarm) is a true SARM: it binds the androgen receptor and is the most studied compound in the class. In clinical trials in older adults and in people with cancer-related muscle loss, it produced modest gains in lean mass. It also lowered testosterone and HDL cholesterol, it has been linked to liver injury in case reports, and it was never approved.
For keeping muscle during a diet, Ostarine is the compound with human data on lean mass; SR9009 has none. For endurance, SR9009’s case rests entirely on mice. Our Ostarine guide covers its evidence and risks.
SR9009 vs Andarine
Andarine (S4) is another SARM, developed by the same company as Ostarine and dropped before approval. It is marketed for cutting, and users commonly report a yellow tint to their vision or poor night vision at higher doses. As a SARM it is expected to suppress testosterone; SR9009 isn’t. Neither has meaningful human trial data for bodybuilding.
SR9009 vs SR9011
SR9011 is the sister compound from the same 2012 paper, with a similar mouse profile and the same lack of human data. It is sometimes sold as the “stronger” version, but no head-to-head comparison in people exists. See SR9011: what the research shows for the details.
The Bottom Line
SR9009 is a useful research tool for studying the body clock and metabolism, but its fat-loss and endurance reputation rests on injected mice, not on people taking capsules.
- No human trial has tested SR9009’s effects, doses or safety.
- It is reported to be poorly absorbed by mouth, so typical oral products may deliver little active drug, and product labels are often unreliable.
- It is not a SARM and isn’t expected to suppress testosterone, but SARMs stacked with it do.
- It is banned by WADA at all times and is not approved for human use anywhere.
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