circadian rhythm is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2025-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
Regulatory and sporting contexts treat SR9009 as a prohibited substance in many elite competitions. Its presence on banned lists reflects concerns about performance enhancement and unknown long-term safety. Analytical chemists have developed methods to detect the parent compound and its metabolites in urine and blood. Literature discussions distinguish between in vitro potency, animal pharmacology, and anecdotal human reports. The latter are difficult to verify because products sold online may lack purity or contain different compounds.
SR9009 is a synthetic small molecule studied as an agonist of the nuclear receptors REV-ERBα and REV-ERBβ. These receptors help regulate circadian rhythms, lipid metabolism, and inflammatory gene expression. In cell and animal experiments, SR9009 alters transcription of clock-controlled genes and metabolic pathways. The compound is not a hormone and does not resemble classical steroid structures. Its activity depends on binding to the ligand-binding domain of REV-ERB, where it can modify corepressor recruitment.
Research interest in SR9009 grew from studies of circadian biology and metabolic disease. Preclinical reports describe effects on exercise capacity, muscle metabolism, and blood lipid levels in rodents, but these findings come from controlled laboratory settings. The compound has low oral bioavailability in animals, which limits systemic exposure after swallowing. Investigators often use injected routes in experiments to achieve measurable plasma concentrations. Human clinical data are sparse, no approved therapeutic product exists, and whether animal effects translate to humans remains an open question.
Regulatory agencies have not approved SR9009 for human therapeutic use. It is typically sold as a research chemical with labels stating that it is not for human consumption. The World Anti-Doping Agency prohibits the substance in sport, generally under the category of non-approved substances. Customs and national laws may restrict importation, sale, or possession. Product quality and legal status can vary by country and vendor, and therapeutic claims are not permitted in regulated advertising because the compound lacks approval.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic REV-ERB agonist | Binds REV-ERBα and REV-ERBβ in preclinical models |
| Molecular formula | C20H24ClN3O4S | Reported for the parent compound |
| CAS Registry Number | 1379686-30-2 | Common identifier in chemical databases |
| Appearance | Off-white to pale yellow solid | Typical research chemical solid |
| Solubility | Soluble in DMSO and ethanol; low in water | Class: small organic molecule |
SR9009 is frequently discussed in fitness and research-chemical contexts, yet it has no approved medical indication. Regulatory agencies have not authorized it for human use, and it is not a standard prescription drug. Some sports organizations list it as a prohibited substance because of its potential performance-enhancing properties. Published human data are sparse, so claims about its effects in people often rely on animal models or anecdotal reports. Quality and identity of online materials can vary widely.
SR9009 is a synthetic small molecule studied as a REV-ERB agonist. REV-ERBα and REV-ERBβ are nuclear receptors that help regulate circadian rhythms and metabolic gene expression. The compound was identified in academic screening efforts to find synthetic ligands for these receptors. In cell and animal studies, SR9009 alters transcription of genes involved in lipid and glucose metabolism, and it can shift circadian behavior. It is not an approved therapeutic agent.
Handling practices for SR9009 focus on minimizing degradation and contamination. The solid is generally stored desiccated at or below -20 °C, protected from light and moisture. Stock solutions are often prepared in dimethyl sulfoxide or ethanol, then aliquoted to avoid repeated freeze–thaw cycles. Aqueous solubility is low, so formulations for animal studies may require cosolvents or suspending agents. Personnel should follow institutional chemical safety procedures, because toxicological data for humans are incomplete.
Regulatory status varies by country and intended use. Major drug agencies have not granted marketing authorization for SR9009 as a medicine, and it is not listed as a controlled substance in many jurisdictions. It is often sold as a research chemical, a category that may fall outside pharmaceutical manufacturing rules. Buyers should verify local laws and supplier documentation, including certificates of analysis. The lack of standardized quality controls raises concerns about identity, purity, and actual content in products marketed online.
=== Neurological pathways === Several brain pathways have been studied, and they seem to contribute to catatonia when they are not functioning properly. However, these studies were unable to determine if the abnormalities they observed were the cause of catatonia or if the catatonia caused the abnormalities. Furthermore, it has been hypothesized that pathways connecting the basal ganglia with the cortex and thalamus are involved in the development of catatonia.
=== Republic of Egypt (from 1953) === King Hussein of Jordan, 1955 Marshal Josip Broz Tito, President of the Federal People's Republic of Yugoslavia, 1956 Prof. Amintore Fanfani, Prime Minister and ad-interim Minister of Foreign Affairs of the Republic of Italy, 1959 Yuri Gagarin, Soviet cosmonaut, 1961 Taha Hussein, Egyptian writer, 1965 Umm kulthum, Egyptian singer and actress, 1965 Mohammed Abdel Wahab, Egyptian singer and composer, 1965 President Jimmy Carter, President of the United States, 1979 Emperor Akihito of Japan Emperor Amha Selassie of Ethiopia Mohammed Burhanuddin, 52nd Da'i al-Mutlaq of the Dawoodi Bohra, 1978 King Bhumibol Adulyadej of Thailand Mohamed ElBaradei, former director general of the International Atomic Energy Agency (IAEA) Queen Elizabeth II, 1975 Birendra Bir Bikram shah Dev, King of Nepal, 1974 Mohammad Reza Pahlavi, Shah of Iran, 1975 Hassaballah El Kafrawy, Egyptian former Minister of Housing Pengiran Anak Haji Mohamed Yusof, prince consort and cheteria of Brunei, 1984 Naguib Mahfouz, Egyptian writer, 1988 King Fahd bin Abdulaziz Al Saud of Saudi Arabia, 1989 Pierre Gemayel, founder of the Lebanese Phalange Emperor Haile Selassie of Ethiopia King Hamad bin Isa Al Khalifa of Bahrain, 2016 King Idris of Libya (Grand Cordon) Ekmeleddin İhsanoğlu, Turkish academic, diplomat and former Secretary-General of the Organisation of Islamic Cooperation (OIC) Émile Lahoud, President of Lebanon, 2000 Makarios III, former president of Cyprus Nelson Mandela, President of South Africa Adly Mansour, former Chief Justice of the Supreme Constitutional Court and former acting President of Egypt King Mohammed VI of Morocco Muhammad Naguib, First President of Egypt Nursultan Nazarbayev, President of Kazakhstan Antonín Novotný, President of Czechoslovakia Sultan Qaboos bin Said al Said of Oman, 1976 Ziaur Rahman, President of Bangladesh Heinrich Rau, East German politician (Grand Cordon), 1961 King Saud bin Abdulaziz Al Saud of Saudi Arabia, 1954 King Norodom Sihanouk of Cambodia William E. Simon, U.S. Secretary of the Treasury Suharto, President of Indonesia Field Marshal Mohamed Hussein Tantawi, former chairman of the Supreme Council of the Armed Forces of Egypt, 2012 Walter Ulbricht, President of East Germany, 1965 George Vasiliou, former president of Cyprus Sir Magdi Habib Yacoub, Egyptian professor of Cardiothoracic Surgery Professor Ahmed Zewail, Egyptian scientist Katerina Sakellaropoulou, President of Greece, 2020 Salva Kiir Mayardit, President of South Sudan, 2020 Haitham bin Tariq, Sultan of Oman, 2023 Narendra Modi, Prime Minister of India, 2023 Mufaddal Saifuddin, 53rd Da'i al-Mutlaq of the Dawoodi Bohras, 2023 Mishal Al-Ahmad Al-Jaber Al-Sabah, Emir of Kuwait, 2024 King Frederik X, King of Denmark, 2024 King Felipe VI, King of Spain, 2025 Donald Trump, President of the United States, 2025
== Histology == The epididymis is covered by a two-layered pseudostratified epithelium. The epithelium is separated by a basement membrane from the connective tissue wall, which has smooth muscle cells. The major cell types in the epithelium are:
=== Membrane spanning === α-Helices are also the most common protein structure element that crosses biological membranes (transmembrane protein), presumably because the helical structure can satisfy all backbone hydrogen-bonds internally, leaving no polar groups exposed to the membrane if the sidechains are hydrophobic. Proteins are sometimes anchored by a single membrane-spanning helix, sometimes by a pair, and sometimes by a helix bundle, most classically consisting of seven helices arranged up-and-down in a ring such as for rhodopsins (see image at right) and other G protein–coupled receptors (GPCRs). The structural stability between pairs of α-Helical transmembrane domains rely on conserved membrane interhelical packing motifs, for example, the Glycine-xxx-Glycine (or small-xxx-small) motif.
Sources: en.wikipedia.org
== Conception and development == Freeze branding was conceived and developed in the mid-1960s by Prof. Roy Keith Farrell. He was then a lecturer at the Veterinary College housed within Washington State University Pullman. Farrell had been inspired by his failure to preserve viable cells under cryogenic conditions. He reasoned that if extremely cold temperatures could ruin cell viability in storage then these temperatures ought to be able to produce the same effect in a living animal, specifically the melanocytes that pigment the growing hair as it leaves the follicle. This was the idea Farrell then tested on the College's herd animals. His success with a variety of subjects including cattle, dogs and squirrels and coolants such as dry ice and liquid nitrogen led him to promote the technique as Cryo-Branding. In 1968 Farrell received patent number 3,362,381 for his Cryo-Branding technique. He granted the Federal Government a permanent non-commercial license. Beverly Pat Farrell, wife of the inventor, (both went by their middle names) would go on to create the popular Alpha-Angle Freeze Mark branding system in the early 1970s. For more on her invention, see Freeze brand § Pat Farrell's Alpha-Angle Freeze Mark below. The cryo-branding technique was first used on a commercial scale under license from Farrell in 1966, initially in Sweden and the year after in the UK.
== Epidemiology == PMOS is the most common hormonal disorder (endocrine disorder) among women of reproductive age. When someone is infertile due to a lack of ovulation, PMOS is the most common cause. According to the World Health Organization (WHO), PMOS affects over 6 to 13% of reproductive-aged women. A 2022 review noted a prevalence between 5% and 18%. The prevalence of PMOS depends on the choice of diagnostic criteria. Using the Rotterdam criteria, around 10–13% of women have PMOS. Based on the NIH criteria, the global prevalence was 5.5%, increasing to approximately 7.1% when using the Androgen Excess Society criteria. Irrespective of the criteria, the prevalence of PMOS is increasing, likely due to an aging population, more awareness, and increasing obesity rates. Prevalence seems fairly even among people with different ethnicities, but may be higher in people from Southeast Asia and the Eastern Mediterranean. But PMOS can express differently. For instance, in African and Hispanic American people with PMOS, there is more insulin resistance compared to other ethnic groups. The same is true for South Asian people with PMOS, who also have more metabolic symptoms and higher BMIs. East Asian women typically have less hirsutism and lower BMI compared to other groups. While early small-scale studies found that transmasculine people were more likely to have PMOS than cis women, this was not found in a larger, more rigorous study.
==== Heritage Guernsey ==== On 2 July Essendon unveiled their Heritage Guernsey. It feature all the names of past premiership players in the background along with the name and signature of club legend John Colman on the breast. Under the signature include the traditional Essendon Football Club motto 'suaviter in modo, fortiter in re' which dates back to the 1870s and translates as 'gentle in manner, resolute in deed.' The most notable change to the guernsey was the removal of the black background to comply with AFL rules requiring each club to provide a clash guernsey. The new Heritage guernsey made its debut during the Round 15 game between St Kilda and Essendon. This marked the end of a 114-year-long tradition as the first time the Essendon Football Club would play an AFL/VFL game without wearing its famous black and red stripe guernsey.
== Research == Magnesium sulfate has been used as an experimental treatment of Irukandji syndrome caused by envenomation by certain species of Irukandji jellyfish, but the efficacy of this treatment remains unproven.
=== Lifespan === The lifespan of a starfish varies considerably among species. For example, Leptasterias hexactis reaches sexual maturity at 20 g (0.7 oz) in two years and lives for about ten years. Pisaster ochraceus matures at 70–90 g (2.5–3.2 oz) in five years and has a maximum recorded lifespan of 34 years.
Sources: en.wikipedia.org
SR9009 is a synthetic small molecule studied as an agonist of the REV-ERB nuclear receptors. It is not an approved medicine, and its effects in humans are not well characterized.
No. It is a synthetic ligand that binds nuclear receptors, not a steroid or peptide hormone. Its activity depends on receptor binding rather than endocrine secretion.
Clinical evidence is limited. Most published data come from cell and animal experiments. Human safety and efficacy remain uncertain.
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.