LC-MS/MS raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-05-10 and is reviewed periodically as new material appears.
Several misconceptions surround SR9009. It is often described as a SARM, a steroid, or an exercise pill, but its known target is the REV-ERB receptor family. Rodent studies have examined exercise capacity and metabolic markers, yet human outcomes remain unproven. Oral bioavailability appears low in animals, and human pharmacokinetics are not well characterized. Online products may contain impurities or different compounds, so identity and purity testing are important for research use.
Analytical chemists detect SR9009 with liquid chromatography-tandem mass spectrometry, commonly abbreviated LC-MS/MS. Sample preparation may involve protein precipitation, liquid-liquid extraction, or solid-phase extraction before analysis. Laboratories can target the parent compound or its metabolites, depending on the matrix and the purpose of testing. Anti-doping methods require sensitive and specific assays because concentrations in biological samples can be low. Reference standards and validated methods are essential for reliable identification and quantification.
Preclinical reports have linked SR9009 to improved endurance and altered energy expenditure in rodents. Such findings have prompted interest in whether REV-ERB activation can influence skeletal muscle metabolism. However, the reported effects depend on dose, route, and experimental model, and replication across laboratories is limited. Human trials have not established comparable outcomes, so claims about exercise performance remain speculative. The absence of controlled human data is a central limitation in interpreting these observations.
The mechanism of action involves binding to REV-ERB receptors and recruiting corepressor complexes, which represses target gene transcription. This contrasts with many nuclear receptor agonists that activate transcription. Downstream effects may include changes in autophagy, mitochondrial biogenesis, and lipid handling, but the precise pathways remain an active area of study. Whether these molecular events translate into meaningful physiological effects in humans is unresolved. Most evidence comes from cultured cells and rodent models rather than human participants.
| Property | Value | Notes |
|---|---|---|
| Regulatory status | Not approved for human use | Research-use-only status in many markets |
| WADA status | Prohibited in sport | Generally listed as a non-approved substance |
| Detection technique | LC-MS/MS | Common for urine and blood analysis |
| Common alias | Stenabolic | Informal market nickname, not a pharmacopoeial name |
| Purity check | HPLC or LC-UV | Independent certificate of analysis is typical |
Most published work on SR9009 consists of preclinical studies. It is widely sold as a research chemical, a category that does not imply safety, efficacy, or pharmaceutical-grade quality. Sports anti-doping organizations have listed SR9009 as a prohibited substance, and its presence in an athlete sample can lead to sanctions. Legal status differs by country; in several jurisdictions it is not approved for human consumption and may be treated as an unapproved new drug.
SR9009 is a synthetic small molecule studied as an agonist of the nuclear receptors REV-ERBα and REV-ERBβ. It is not a steroid, peptide, or natural hormone. In scientific literature, it appears under the code SR9009 and in non-scientific contexts as Stenabolic. The compound was identified through chemical screening efforts aimed at targeting circadian clock components. Its status remains investigational, and no regulatory agency has approved it as a human medicine.
Charles Darwin in his 1878 book The Effects of Cross and Self-Fertilization in the Vegetable Kingdom at the start of chapter XII noted "The first and most important of the conclusions which may be drawn from the observations given in this volume, is that generally cross-fertilisation is beneficial and self-fertilisation often injurious, at least with the plants on which I experimented." An important adaptive benefit of outcrossing is that it allows the masking of deleterious mutations in the genome of progeny. This beneficial effect is also known as hybrid vigour or heterosis. Once outcrossing is established, subsequent switching to inbreeding becomes disadvantageous since it allows expression of the previously masked deleterious recessive mutations, commonly referred to as inbreeding depression. Unlike in higher animals, where parthenogenesis is rare, asexual reproduction may occur in plants by several different mechanisms. The formation of stem tubers in potato is one example. Particularly in arctic or alpine habitats, where opportunities for fertilisation of flowers by animals are rare, plantlets or bulbs may develop instead of flowers, replacing sexual reproduction with asexual reproduction and giving rise to clonal populations genetically identical to the parent. This is one of several types of apomixis that occur in plants. Apomixis can also happen in a seed, producing a seed that contains an embryo genetically identical to the parent.
=== Retirement === McVeigh retired from professional Australian rules football on 29 August 2012. Injuries to his hip, knee and hamstring restricted McVeigh to only three games during the 2012 season. McVeigh stated, "It's a decision that I've been to-ing and fro-ing with for about eight weeks. But I've been very fortunate to part ways with the club on really good terms," during a press conference at Windy Hill. McVeigh shared the role of Vice-Captain of the Essendon Football Club with David Hille for most of his career. McVeigh played a total of 232 games and kicked 107 goals during his playing career for Essendon from 1999 until 2012.
Circumcision is near-universal among Jews. The mitzvah of circumcision on the eighth day of life is considered among the most important commandments in Judaism. Barring extraordinary circumstances, failure to undergo the rite is seen by followers of Judaism as leading to a state of Kareth: the extinction of the soul and denial of a share in the world to come. Reasons for biblical circumcision include to show off "patrilineal descent, sexual fertility, male initiation, cleansing of birth impurity, and dedication to God".
==== Hopper cars ==== In 1969, the Northern Pacific Railroad ordered some modified covered hopper cars from American Car and Foundry for transporting perishable food in bulk. The 55-foot (16.76 m)-long cars were blanketed with a layer of insulation, equipped with roof hatches for loading, and had centerflow openings along the bottom for fast discharge. A mechanical refrigeration unit was installed at each end of the car, with sheet-metal ducting forcing cool air into the cargo compartments. The units, rated at 100 short tons (91 t; 89 long tons) capacity (more than twice that of the largest conventional refrigerator car of the day), were economical to load and unload, as no secondary packaging was required. Apples, carrots, onions, and potatoes were transported in this manner with moderate success. Oranges, on the other hand, tended to burst under their own weight, even after wooden baffles were installed to distribute the load better. The Santa Fe Railway leased 100 of the hoppers from ACF, and in April 1972, purchased 100 new units, known as "Conditionaire" cars. The cars' irregular, orange-colored outer surface (though darker than the standard AT&SF yellow-orange used on reefers) tended to collect dirt easily and proved difficult to clean. Santa Fe eventually relegated the cars to more typical, non-refrigerated applications.
Sources: en.wikipedia.org
Karen M. Frank is an American clinical pathologist and microbiologist researching the pathogenesis of Staphylococcus aureus pneumonia and resistant gram-negative bacteria. She is a senior clinician, principal investigator, and chief of laboratory medicine at the National Institutes of Health Clinical Center.
== Nomenclature == Signal peptides are not to be confused with the leader peptides sometimes encoded by leader mRNA, although both are sometimes ambiguously referred to as "leader peptides." These other leader peptides are short polypeptides that do not function in protein localization, but instead may regulate transcription or translation of the main protein, and are not part of the final protein sequence. This type of leader peptide primarily refers to a form of gene regulation found in bacteria, although a similar mechanism is used to regulate eukaryotic genes, which is referred to as uORFs (upstream open reading frames).
=== Available forms === Propoxyphene was initially introduced as propoxyphene hydrochloride. Shortly before the patent on propoxyphene expired, propoxyphene napsylate form was introduced to the market. The napsylate salt (the salt of naphthalene-2-sulfonic acid) is claimed to be less prone to non-medical use, because it is almost insoluble in water, so cannot be used for injection. Napsylate also gives lower peak blood level. Because of different molar mass, a dose of 100 mg of propoxyphene napsylate is required to supply an amount of propoxyphene equivalent to that present in 65 mg of propoxyphene hydrochloride. Before the FDA-directed recall, dextropropoxyphene HCl was available in the United States as a prescription formulation combined with paracetamol (acetaminophen) in ratio from 30 mg / 600 mg to 100 mg / 650 mg (or 100 mg / 325 mg in the case of Balacet), respectively, usually named Darvocet. In Australia, dextropropoxyphene is available on prescription, both as a combined product (32.5 mg dextropropoxyphene per 325 mg paracetamol branded as Di-gesic, Capadex, or Paradex; it is also available in pure form (100 mg capsules) known as Doloxene, however its use has been restricted.
== Formation == Initial funding for the formation of Onyx came from biotechnology firm Chiron Corporation (granted a 43% stake in the new company) and venture capital investors: Avalon Ventures, Institutional Venture Partners (IVP), J. H. Whitney & Company and Kleiner Perkins. McCormick had been working on cancer treatments at Chiron before he was selected as vice president of research at the newly formed company, leading the company's research program. The acting president of the firm at its inception was Samuel D. Colella, a partner at early investor, IVP.
== History == The 1950s to 1970s represented the golden age of antibiotic discovery, where countless new classes of antibiotics were discovered to treat previously incurable diseases such as tuberculosis and syphilis. However, since that time the discovery of new classes of antibiotics has been almost nonexistent, and represents a situation that is especially problematic considering the resiliency of bacteria shown over time and the continued misuse and overuse of antibiotics in treatment. Already in 1940, in their letter to the editor of Nature journal, Abraham and Chain identified the enzyme penicillinase as responsible for the deactivation of penicillin in penicillin-resistant bacteria. This discovery was the first step in understanding the mechanisms of microbial resistance to β-lactam antibiotics. The phenomenon of antimicrobial resistance caused by overuse of antibiotics was predicted as early as 1945 by Alexander Fleming who said "The time may come when penicillin can be bought by anyone in the shops. Then there is the danger that the ignorant man may easily under-dose himself and by exposing his microbes to nonlethal quantities of the drug make them resistant." Without the creation of new and stronger antibiotics an era where common infections and minor injuries can kill, and where complex procedures such as surgery and chemotherapy become too risky, is a very real possibility. Antimicrobial resistance can lead to epidemics of enormous proportions if preventive actions are not taken.
Sources: en.wikipedia.org
Legality depends on the country and the intended use. In many places it is not approved as a medicine and may be sold only as a research chemical. Importation or possession can be restricted, and sports organizations prohibit it.
Anti-doping laboratories typically use LC-MS/MS to detect SR9009 or its metabolites in urine or blood. The exact assay depends on the laboratory and the testing program. Detection can be challenging because the compound may be rapidly metabolized and present at low levels.
Stenabolic is an informal nickname used in online fitness and research-chemical markets, not an official drug name. It likely references reported effects on endurance in rodent studies. The nickname does not imply approval or proven human benefit.
It is a synthetic compound that acts as an agonist at REV-ERBα and REV-ERBβ. It is used mainly as a research chemical to study circadian and metabolic pathways. It is not approved for human therapeutic use.