A practical reference on metabolite: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-12-07. Anything still debated is marked as such rather than presented as settled.
Cardarine is frequently described as a fat-burning or endurance-enhancing supplement, but these claims exceed the available evidence. The compound is not a hormone, steroid, or selective androgen receptor modulator. Research articles discuss it as a tool compound for studying PPARδ biology, while anti-doping literature focuses on its abuse and detection. Quality of unapproved products is uncertain, and independent analyses have found impurities or incorrect labeling. Open questions include whether human cancer risk resembles that seen in rodents and how often non-athletes use the substance.
Cardarine has no approved therapeutic indication and is not marketed as a medicine. The World Anti-Doping Agency lists GW501516 as a prohibited substance at all times, covering both in-competition and out-of-competition periods. National laws vary: some countries treat it as an unapproved drug subject to import controls, while others have specific restrictions on sale for human consumption. It is often sold as a research chemical, a label that does not imply safety or legality. Enforcement actions have targeted online vendors and shipments.
Anti-doping laboratories identify GW501516 and related metabolites using liquid chromatography coupled with tandem mass spectrometry. Urine is the most common matrix, though blood and dried blood spots may also be analyzed. The method targets the parent compound and phase I and phase II metabolites, which extend the detection window. Because the substance is prohibited at all times, athletes can be tested outside competition. Detection limits and windows depend on the assay, sample type, and individual metabolism.
Laboratory detection of cardarine typically involves sample preparation followed by chromatographic separation and mass spectrometric identification. Urine is the most common matrix for anti-doping tests, though blood and hair have also been explored. Methods can target the parent compound or its metabolites, depending on the expected window of detection. Reference standards are required for accurate quantification. Matrix effects and dilution can influence results, so laboratories use internal standards and validation protocols. The exact detection window varies with dose, route, and individual metabolism.
A common misconception is that cardarine has been proven safe for human use. In reality, human clinical data are limited, and long-term animal studies have raised concerns about cancer. Another misconception is that it is a supplement or vitamin-like compound. It is a synthetic research chemical with no approved medical indication. Scientific discussion often focuses on its mechanism and detection rather than therapeutic use. Regulatory and anti-doping literature treats it primarily as a prohibited substance.
| Property | Value | Notes |
|---|---|---|
| Regulatory status | Prohibited in sport; not approved as medicine | Listed by WADA at all times. |
| Common synonyms | GW501516, GW-501516, endurobol | Cardarine is a colloquial name. |
| Typical analytical method | LC-MS/MS | Detects parent compound and metabolites. |
| Common test matrix | Urine | Blood and dried blood spots also possible. |
| Legal classification | Varies by country | Often treated as unapproved drug or research chemical. |
Laboratory handling focuses on identity, purity, and stability. Reference standards are typically stored cold and dry, protected from light, because solutions can degrade over time. Analytical checks may use high-performance liquid chromatography with ultraviolet detection or mass spectrometry. Impurities and related substances can be separated chromatographically and compared with a known standard. Because cardarine is not an approved drug, compendial monographs are absent, and laboratories often rely on in-house methods. Reported purity varies among unregulated products and should not be assumed from a label.
GW501516 binds and activates PPARδ, a nuclear receptor that influences transcription of genes involved in fatty acid oxidation and energy use. Activation shifts some metabolic pathways in preclinical models, which is why the compound has been studied for lipid disorders and exercise-related endpoints. The exact downstream effects in humans are incompletely mapped. PPARδ is expressed in many tissues, including skeletal muscle, liver, and adipose tissue, so broad activation may have varied consequences. Researchers continue to examine how selective or partial activation might alter the balance between benefits and risks.
Because cardarine is not an approved medicine, no pharmacopeial monograph defines its identity, purity, or storage requirements. Laboratories typically rely on in-house methods and reference standards when testing materials labeled as GW501516. Certificates of analysis may report purity and identity for a specific batch, but their scope varies and they do not guarantee safety or legal status. Independent verification can include high-performance liquid chromatography, mass spectrometry, nuclear magnetic resonance, and elemental analysis. The distinction between research chemical labeling and human use is significant because quality standards and oversight differ.
Cardarine can be detected in biological samples and product materials using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The method separates compounds by chromatography and identifies them by mass-to-charge transitions, allowing low-level detection in urine or blood. Sample preparation often involves enzymatic hydrolysis, solid-phase extraction, or protein precipitation. Certified reference materials and isotope-labeled internal standards improve quantification. Detection windows depend on metabolism, matrix, and assay sensitivity, so no single universal window applies.
==== No Más Bebes (2015) ==== The film No Más Bebes tells the stories of several Chicana women sterilized at the Los Angeles County-USC Medical Center in the 1970s. They were part of a larger group of women who underwent sterilization without a proper form of consent. Many women only learned of their sterilization months and perhaps years later. Antonia Hernandez, the plaintiff's attorney in the Madrigal v. Quilligan (1978) lawsuit, is largely responsible for relaying such information, as she spent significant amounts of time patrolling Mexican American barrios searching for Chicana women listed on hospital documents. Hernandez and Charles Nabarette learned of the coerced tubal ligations from Dr. Bernard Rosenfeld, a resident at the teaching hospital. In the documentary, he compares the medical center's practices to the sterilization of Jews in Nazi Germany at the beginning of World War II. Consequently, he was terminated for acting as a whistleblower, and nearly at risk of losing his medical license. The ten women who filed the lawsuit were U.S. citizens with varying proficiencies in the English language. The film reveals many justifications for the tubal ligations performed, including rushed, last-minute decision-making, misunderstanding of medical jargon, language barriers, and written signatures of consent. Dr. Edward James Quilligan, the main defendant on trial, claims that the hospital was simply “practicing good medicine” in one of his interviews for the documentary.
Isothermal titration calorimetry (ITC), is considered as the most quantitative technique available for measuring the thermodynamic properties of protein–protein interactions and is becoming a necessary tool for protein–protein complex structural studies. This technique relies upon the accurate measurement of heat changes that follow the interaction of protein molecules in solution, without the need to label or immobilize the binding partners, since the absorption or production of heat is an intrinsic property of virtually all biochemical reactions. ITC provides information regarding the stoichiometry, enthalpy, entropy, and binding kinetics between two interacting proteins. Microscale thermophoresis (MST), is a new method that enables the quantitative analysis of molecular interactions in solution at the microliter scale. The technique is based on the thermophoresis of molecules, which provides information about molecule size, charge and hydration shell. Since at least one of these parameters is typically affected upon binding, the method can be used for the analysis of each kind of biomolecular interaction or modification. The method works equally well in standard buffers and biological liquids like blood or cell-lysate. It is a free solution method which does not need to immobilize the binding partners. MST provides information regarding the binding affinity, stoichiometry, competition and enthalpy of two or more interacting proteins.
Insulin deficiency diabetes or primary diabetes, which refers to the destruction of the beta cells of the pancreas and their inability to produce insulin. Insulin resistance diabetes or secondary diabetes, which describes the resistance to insulin caused by other medical conditions or by hormonal drugs. While the occurrence of beta cell destruction is known, all of the processes behind it are not. Canine primary diabetes mirrors type 1 human diabetes in the inability to produce insulin and the need for exogenous replacement of it, but the target of canine diabetes autoantibodies has yet to be identified. Breed and treatment studies have been able to provide some evidence of a genetic connection. Studies have furnished evidence that canine diabetes has a seasonal connection not unlike its human Type 1 diabetes counterpart, and a "lifestyle" factor, with pancreatitis being a clear cause. This evidence suggests that the disease in dogs has some environmental and dietary factors involved. Canine obesity causes the corresponding diabetes in dogs also known as canine diabetes (Hoeing 2014). Secondary diabetes may be caused by use of steroid medications, the hormones of estrus, acromegaly, (spaying can resolve the diabetes), pregnancy, or other medical conditions such as Cushing's disease. In such cases, it may be possible to treat the primary medical problem and revert the animal to non-diabetic status. Returning to non-diabetic status depends on the amount of damage the pancreatic insulin-producing beta cells have sustained.
The four substrates of this enzyme are propylene, reduced nicotinamide adenine dinucleotide (NADH), oxygen, and a proton. Its products are propylene oxide, oxidised NAD+, and water. This enzyme is an oxidoreductase, acting on paired donors, with molecular oxygen as oxidant and incorporating one of its atoms. The systematic name of this enzyme class is alkene,NADH:oxygen oxidoreductase. This enzyme is also called alkene epoxygenase. It contains a Rieske type of ferredoxin.
Sources: en.wikipedia.org
THC (Delta-9 tetrahydrocannabinol), the active component in cannabis. methamphetamine, also known as "ice", "crystal" and "crank". MDMA (Methylenedioxymethamphetamine), which is known as ecstasy. In February 2016 a New South Wales magistrate "acquitted a man who tested positive for cannabis". He had been arrested and charged after testing positive during a roadside drug test, despite not having smoked for nine days. He was relying on advice previously given to him by police.
== Career == Laidlaw attended the University of Oregon, where he tried, and was discouraged by, punched card computer programming. While working at the Pacific Gas and Electric Company, Laidlaw wrote the novel Dad's Nuke, which he followed with the novels 37th Mandala, Kalifornia and The Orchid Eater. He wrote a series of articles for Wired profiling the video game developer id Software. He was commissioned to write a novelization of the FMV adventure game Gadget by the Japanese developer Synergy. Gadget was unsuccessful, but Laidlaw was excited by the creative process of game development. While writing another id profile, he began asking about game design and exploring opportunities in the industry.
In other words, short-term high concentrations and long-term low concentrations of estradiol appear to have the same degree of effect in terms of genomic estrogenic signaling, at least in terms of breast cell proliferation over a 24-hour period. On the other hand, non-genomic actions of estradiol, such as signaling through membrane estrogen receptors like the GPER, may be reduced with short-term high concentrations of estradiol relative to more sustained levels. For instance, although daily intranasal administration of estradiol is associated with comparable clinical effectiveness (e.g., for hot flashes) relative to longer acting routes of estradiol administration in postmenopausal women, it is also associated with significantly lower rates of breast tension (tenderness and enlargement) relative to longer acting estradiol routes, and this is thought to reflect comparatively diminished non-genomic signaling.
==== 17OHP subpathway ==== The first step of this pathway is the 5α-reduction of 17OHP to 5α-pregnan-17α-ol-3,20-dione (referred to as 17OHDHP or 17α-hydroxy-dihydroprogesterone). The reaction is catalyzed by SRD5A1. 17OHDHP is then converted to 5α-pregnane-3α,17α-diol-20-one (5α-Pdiol) via 3α-reduction by a 3α-hydroxysteroid dehydrogenase isozyme (AKR1C2 and AKR1C4) or HSD17B6, that also has 3α-reduction activity. The pathway then proceeds from 5α-Pdiol the same way as the pathway that starts from P4, i.e. 5α-Pdiol → AST → 3α-diol → DHT. The pathway can be summarized as: 17OHP → 17OHDHP → 5α-Pdiol → AST → 3α-diol → DHT.
== Distinction between a LIMS and a LIS == Until recently, the LIMS and Laboratory Information System (LIS) have exhibited a few key differences, making them noticeably separate entities. A LIMS traditionally has been designed to process and report data related to batches of samples from biology labs, water treatment facilities, drug trials, and other entities that handle complex batches of data. A LIS has been designed primarily for processing and reporting data related to individual patients in a clinical setting. A LIMS may need to satisfy good manufacturing practice (GMP) and meet the reporting and audit needs of the regulatory bodies and research scientists in many different industries. A LIS, however, must satisfy the reporting and auditing needs of health service agencies e.g. the hospital accreditation agency, HIPAA in the US, or other clinical medical practitioners. A LIMS is most competitive in group-centric settings (dealing with "batches" and "samples") that often deal with mostly anonymous research-specific laboratory data, whereas a LIS is usually most competitive in patient-centric settings (dealing with "subjects" and "specimens") and clinical labs. An LIS is regulated as a medical device by the FDA, and the companies that produce the software are therefore liable for defects. Due to this, a LIS can not be customized by the client.
Sources: en.wikipedia.org
Legal status varies by country. It is not approved as a medicine, and it is prohibited in sport. Some jurisdictions restrict import, sale, or possession.
Laboratories use liquid chromatography-tandem mass spectrometry to detect GW501516 and its metabolites. Urine is commonly tested, and testing can occur in and out of competition.
No, cardarine is not a SARM. It is a PPARδ agonist, which acts on a different receptor. The two classes are often confused in online discussions.
Yes, WADA prohibits cardarine as a PPARδ agonist. It appears on the prohibited list and can be detected in urine or blood. Athletes using it risk sanctions.