freeze-thaw comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2025-11-02. Numbers and descriptions here follow the published literature rather than marketing material.
In rodent studies, SR9009 has been reported to increase mitochondrial content in skeletal muscle and improve exercise endurance under some conditions. These findings led to popular descriptions such as an exercise mimetic, although that term oversimplifies the biology. Effects vary by dose, timing, tissue, and model. The compound's influence on circadian pathways means that time of administration can matter in experiments. Whether similar metabolic changes occur in humans remains largely unexplored in controlled published trials.
Pharmacokinetic data for SR9009 are limited in published literature. Some reports indicate low oral bioavailability and rapid clearance in animals, which complicates interpretation of exposure and effect. Researchers often use injected routes in preclinical work to achieve measurable systemic levels. Analytical studies rely on mass spectrometry to detect the parent compound and its metabolites. Questions about tissue distribution, active metabolites, and long-term consequences remain open. Species differences in metabolism can affect observed half-life and target engagement.
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 and metabolic gene expression. In laboratory experiments, SR9009 binds these receptors and alters transcription of genes involved in lipid handling, glucose metabolism, and mitochondrial function. It is not a naturally occurring compound and has no approved therapeutic use. Research interest stems from its ability to modify energy metabolism in cells and animal models.
For long-term storage, SR9009 is typically kept as a solid at low temperature, protected from moisture and light. Desiccated conditions limit hydrolysis, while opaque containers reduce photochemical breakdown. Solutions are less stable than solids and are often stored frozen in aliquots to avoid repeated freeze-thaw cycles. Stability data are not standardized across all suppliers, so users should rely on certificate-of-analysis information when available. Degradation may appear as color change, precipitate, or decreased chromatographic purity.
Laboratory identification of SR9009 typically relies on chromatographic separation coupled to mass spectrometry, often with ultraviolet detection as a secondary check. Nuclear magnetic resonance spectroscopy can confirm molecular structure when a reference standard is available. Because many suppliers sell the compound as a research chemical, independent identity testing is important for experimental reproducibility. A single retention time is not sufficient proof of identity, especially when related compounds may be present. Purity assessments usually report a percentage based on area normalization.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic small-molecule REV-ERB agonist | Not a hormone or natural product |
| Primary targets | REV-ERBα and REV-ERBβ | Nuclear receptors involved in circadian and metabolic regulation |
| Appearance | White to off-white solid | Typical for purified research samples |
| Solubility | Soluble in DMSO and ethanol; low water solubility | Laboratory solubility depends on solvent and purity |
| Common synonyms | SR9009; Stenabolic | Stenabolic is a colloquial name, not a formal chemical name |
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.
In laboratory settings, SR9009 is commonly identified by its molecular structure and its interaction with REV-ERB receptors. Vendors may list it under synonyms such as Stenabolic or REV-ERB agonist, but those names do not define purity or identity. Analytical confirmation typically uses high-performance liquid chromatography with ultraviolet detection or liquid chromatography–mass spectrometry. A reference standard is needed to compare retention time and mass spectrum, because the compound can be confused with related research chemicals.
President Biden signs his first executive orders reversing several Trump administration actions, including rejoining the Paris Agreement and the World Health Organization, repealing the 2017 travel bans, ending funding for the Mexico–United States border wall, and revoking the permit for the Keystone XL pipeline. January 21 – The Food and Drug Administration (FDA) approves Cabenuva as a complete regimen for the treatment of HIV/AIDS. January 22 – Recreational cannabis sales begin in Arizona. January 24 COVID-19 pandemic: Nationwide confirmed COVID-19 cases surpass 25 million. The Tampa Bay Buccaneers advance to Super Bowl LV after a 31–26 victory against the Green Bay Packers, the first time an NFL team will play the Super Bowl on their home field. January 25 President Biden repeals the Trump administration's ban on transgender personnel in the military. COVID-19 pandemic: Minnesota reports the first national case of the Lineage P.1 variant of SARS-CoV-2. Dominion Voting Systems sues former New York City mayor Rudy Giuliani, accusing him of defamation during the 2020 presidential election. January 26 COVID-19 pandemic: The Biden administration announces it will purchase 200 million COVID-19 vaccine doses from Pfizer/BioNTech and Moderna, in addition to the prior order of 400 million. January 27 The U.S. Army announces new personal grooming and appearance standards, relaxing rules regarding makeup and jewelry and allowing for more diverse hairstyles.
The chemical nature of the stationary phase. The stationary phase can be coated with some ligands at different bonding densities (how many ligands are bonded per surface area). The composition of the mobile phase. The mobile phase may be made of one solvent, or a mixture of several solvents. The solvents can be mixed at different ratios. Different mobile phases have different properties, such as polarity. When a mobile phase consists of mostly one solvent, with some other solvents added in small amounts, those other solvents are called "mobile phase modifiers". The pH of the mobile phase, which affect the ionization state of the solutes and their polarity. This can be changed with additives such as buffers. Usually, the stationary phase is made of a layer of hydrophobic substrate bonded to the surface of porous silica gel particles. The particles come in various shapes (spheric, irregular), at different diameters (sub-2, 3, 5, 7, 10 μm), with varying pore diameters (60, 100, 150, 300 Å). The particle diameters are often given as mesh numbers. For example, 2500-mesh corresponds to a particle diameter of 5 μm. The hydrophobic substrates are generally alkyl chains, such as C3, C4, C8, C18, or more. The longer the chain, the longer the sample components will be retained. It would make the resolution power higher, but also make the chromatography take longer to run. Most current methods of separation of biomedical materials use C18 columns, sometimes called by trade names, such as ODS (octadecylsilane) or RP-18 (reverse phase 18).
Cardiovascular: dyslipidemia (e.g., increased LDLTooltip low-density lipoprotein levels, decreased HDLTooltip high-density lipoprotein levels, reduced apo-A1Tooltip apolipoprotein A1 levels), atherosclerosis, elevated hematocrit, hypertension, left ventricular hypertrophy, cardiomyopathy, myocardial hypertrophy, polycythemia/erythrocytosis, arrhythmias, thrombosis (e.g., embolism, stroke), myocardial infarction, sudden death. Hepatic: elevated liver function tests (ASTTooltip aspartate aminotransferase, ALTTooltip alanine aminotransferase, bilirubin, LDHTooltip lactic dehydrogenase, ALPTooltip alkaline phosphatase), hepatotoxicity, jaundice, hepatic steatosis, hepatocellular adenoma, hepatocellular carcinoma, cholestasis, peliosis hepatis; all mostly or exclusively with 17α-alkylated AAS. Renal: renal hypertrophy, nephropathy, acute renal failure (secondary to rhabdomyolysis), focal segmental glomerulosclerosis, renal cell carcinoma. Others: glucose intolerance, insulin resistance, immune dysfunction.
== Protein breakdown == Protein catabolism is the process by which proteins are broken down to their amino acids. This is also called proteolysis and can be followed by further amino acid degradation.
=== Medication === Opioid replacement therapy (ORT), also known as opioid substitution therapy (OST), Medication for Addiction Treatment (MAT), or Medications for Opioid Use Disorder (MOUD), involves replacing an opioid, such as heroin. Commonly used drugs for ORT are methadone and buprenorphine/naloxone (Suboxone), which are taken under medical supervision. Buprenorphine/naloxone is usually preferred over methadone because of its safety profile, which is considered significantly better, primarily regarding its risk of overdose and effects on the heart (QTc prolongation). Buprenorphine/naloxone, methadone, and naltrexone are approved by the U.S. Food and Drug Administration (FDA) for medication-assisted treatment (MAT). In the U.S., the Substance Abuse and Mental Health Services Administration (SAMHSA) certifies opioid treatment programs (OTPs), where methadone can be dispensed at methadone clinics. As of 2023, the Waiver Elimination (MAT Act), also known as the "Omnibus Bill", removed the federal requirement for medical providers to obtain a waiver to prescribe buprenorphine, in an attempt to increase access to OUD treatment. The driving principle behind ORT is the patient's reclamation of a self-directed life. ORT facilitates this process by reducing symptoms of drug withdrawal and drug cravings. In some countries (not the U.S. or Australia), regulations enforce a limited time for people on ORT programs that conclude when a stable economic and psychosocial situation is achieved.
Sources: en.wikipedia.org
N,O-Didesmethyltramadol (tramadol metabolite M5) is an opioid derivative which is one of two active metabolites of the opioid analgesic medication tramadol. It is many times less potent than the other active metabolite O-Desmethyltramadol but is still more potent as a mu opioid receptor agonist than tramadol itself, unlike the other metabolites N-desmethyltramadol, N,N-didesmethyltramadol, and N,N,O-tridesmethyltramadol which are entirely without opioid activity. As with tramadol and O-desmethyltramadol it is found as a mixture of the (1S,2S)- and (1R,2R)-enantiomers, although the separate enantiomers of N,O-didesmethyltramadol have not been studied individually. It is specifically listed as a Schedule I drug in Canada, presumably due to concerns it may be subject to abuse as a designer drug in a similar manner to other opioid active metabolites such as O-desmethyltramadol and nortilidine.
==== Subcultural model ==== Historically, addiction has been viewed from the etic perspective, defining users through the pathology of their condition. As reports of drug use rapidly increased, the cultural model found application in anthropological research exploring western drug subculture practices. The approach evolved from the ethnographic exploration into the lived experiences and subjectivities of 1960s and 70s drug subcultures. The publication "Taking care of business", by Edward Preble and John J. Casey, documented the daily lives of New York street-based intravenous heroin users in detail, providing insight into the dynamic social worlds and activities that surrounded their drug use. Singer writes that this work reframed substance use as a social phenomenon rather than a matter of immorality or deviance. The prevailing culture can influence drug-taking behaviors, along with the physical and psychological effects of the drug. To marginalized individuals, drug subcultures can provide social connection, symbolic meaning, and socially constructed purpose that they may feel is unattainable through conventional means. On this account, a biosocial approach is required for a holistic understanding of addiction.
Nonlinear two-dimensional infrared spectroscopy is the infrared version of correlation spectroscopy. Nonlinear two-dimensional infrared spectroscopy is a technique that has become available with the development of femtosecond infrared laser pulses. In this experiment, first a set of pump pulses is applied to the sample. This is followed by a waiting time during which the system is allowed to relax. The typical waiting time lasts from zero to several picoseconds, and the duration can be controlled with a resolution of tens of femtoseconds. A probe pulse is then applied, resulting in the emission of a signal from the sample. The nonlinear two-dimensional infrared spectrum is a two-dimensional correlation plot of the frequency ω1 that was excited by the initial pump pulses and the frequency ω3 excited by the probe pulse after the waiting time. This allows the observation of coupling between different vibrational modes; because of its extremely fine time resolution, it can be used to monitor molecular dynamics on a picosecond timescale. It is still a largely unexplored technique and is becoming increasingly popular for fundamental research. As with two-dimensional nuclear magnetic resonance (2DNMR) spectroscopy, this technique spreads the spectrum in two dimensions and allows for the observation of cross peaks that contain information on the coupling between different modes. In contrast to 2DNMR, nonlinear two-dimensional infrared spectroscopy also involves the excitation to overtones.
== Mechanism == Obstructive sleep apnea The causes of obstructive sleep apnea are complex and individualized, but typical risk factors include narrow pharyngeal anatomy and craniofacial structure. When anatomical risk factors are combined with non-anatomical contributors such as an ineffective pharyngeal dilator muscle function during sleep, unstable control of breathing (high loop gain), and premature awakening to mild airway narrowing, the severity of the OSA rapidly increases as more factors are present. When breathing is paused due to upper airway obstruction, carbon dioxide builds up in the bloodstream. Chemoreceptors in the bloodstream note the high carbon dioxide levels. The brain is signaled to awaken the person, which clears the airway and allows breathing to resume. Breathing normally will restore oxygen levels and the person will fall asleep again. This carbon dioxide build-up may be due to the decrease of output of the brainstem regulating the chest wall or pharyngeal muscles, which causes the pharynx to collapse. As a result, people with sleep apnea experience reduced or no slow-wave sleep and spend less time in REM sleep. Central sleep apnea There are two main mechanism that drive the disease process of CSA, sleep-related hypoventilation and post-hyperventilation hypocapnia. The most common cause of CSA is post-hyperventilation hypocapnia secondary to heart failure. This occurs because of brief failures of the ventilatory control system but normal alveolar ventilation.
A pulmonary embolism is a blood clot that becomes lodged in the pulmonary arteries. The majority of emboli arise because of deep vein thrombosis in the legs. Pulmonary emboli may be investigated using a ventilation/perfusion scan, a CT scan of the arteries of the lung, or blood tests such as the D-dimer. Pulmonary hypertension describes an increased pressure at the beginning of the pulmonary artery that has a large number of differing causes. Other rarer conditions may also affect the blood supply of the lung, such as granulomatosis with polyangiitis, which causes inflammation of the small blood vessels of the lungs and kidneys. A lung contusion is a bruise caused by chest trauma. It results in hemorrhage of the alveoli causing a build-up of fluid which can impair breathing, and this can be either mild or severe. The function of the lungs can also be affected by compression from fluid in the pleural cavity pleural effusion, or other substances such as air (pneumothorax), blood (hemothorax), or rarer causes. These may be investigated using a chest X-ray or CT scan, and may require the insertion of a surgical drain until the underlying cause is identified and treated.
Sources: en.wikipedia.org
It is a synthetic research compound that activates REV-ERB nuclear receptors. It is not an approved drug or dietary supplement. Most information comes from cell and animal studies.
It binds REV-ERBα and REV-ERBβ and changes transcription of metabolic genes. This can affect circadian rhythm, lipid use, and mitochondrial function. The full downstream effects are still under study.
No. Some rodent studies show increased endurance, but controlled human trials are lacking. Claims about human performance are not established by published evidence.
Liquid chromatography with mass spectrometry is a common approach. Ultraviolet detection and nuclear magnetic resonance can support identification when suitable standards are available.