Nuclear receptor 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.
Updated 2026-03-19. Numbers and descriptions here follow the published literature rather than marketing material.
GW501516 acts as a selective agonist at PPARδ, a nuclear receptor that regulates transcription of genes involved in lipid handling and energy metabolism. Activation of PPARδ in preclinical models increases fatty acid oxidation, mitochondrial biogenesis, and exercise endurance in rodents. These effects have made the compound a subject of metabolic research and also a target for sport anti-doping rules. In humans, however, controlled studies are limited, and whether similar endurance or metabolic changes occur at tolerated exposures remains an open question. The receptor’s broad tissue distribution also means downstream effects may vary by organ and condition.
Detection of GW501516 in biological samples generally relies on liquid chromatography coupled with tandem mass spectrometry. Urine is a common matrix in anti-doping analysis, while blood or plasma may be used in research settings. Sample preparation can involve enzymatic hydrolysis, protein precipitation, or solid-phase extraction before instrumental analysis. Because the compound undergoes metabolism, assays may target the parent molecule, one or more metabolites, or both. Detection windows are not fixed; they depend on factors such as dose, route, individual metabolism, and assay sensitivity. Reference standards are required for accurate identification and quantification.
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.
Cardarine is explicitly prohibited by the World Anti-Doping Agency under the class of PPARδ agonists. Its presence in urine or blood samples can be detected using mass spectrometry-based methods, often liquid chromatography-tandem mass spectrometry. Athletes who test positive may face sanctions, including bans from competition. The compound is also regulated as a prescription-only or unapproved drug in many countries. Enforcement varies by jurisdiction, and some regions treat it as a controlled substance. Online sales may occur despite these restrictions, creating quality and legal risks.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Visual description for typical solid reference material. |
| Solubility | Poorly soluble in water; soluble in DMSO | Solubility depends on solvent, purity, and form. |
| Storage | Cool, dry, protected from light | Long-term storage often uses low temperature and desiccant. |
| Common analytical method | LC-MS/MS | Used for detection and quantification in biological matrices. |
| Common synonyms | GW-501516; GW501516; endurobol | Naming varies among literature, vendors, and databases. |
Published studies have examined GW501516 in animal models of obesity, insulin resistance, and exercise endurance. Early human trials reportedly ended, and development was discontinued after preclinical findings raised concerns about cancer in some rodent studies. Regulatory agencies have not approved cardarine for any medical use. Its availability through non-pharmaceutical channels raises questions about identity, purity, and legal status that are separate from its laboratory pharmacology. Those questions are often addressed through analytical testing rather than assumptions about product labels.
Cardarine is a common name for GW501516, also GW-1516, a synthetic compound developed as a peroxisome proliferator-activated receptor delta (PPARδ) agonist. It belongs to a class of agents that modulate gene transcription related to lipid and energy metabolism. The compound was studied in preclinical and early clinical research for metabolic and cardiovascular conditions, but it did not progress to approved therapeutic use. Its name appears in fitness and sports contexts despite not being approved as a drug.
PPARδ is a nuclear receptor that influences transcription of genes involved in fatty acid oxidation, lipid transport, and energy homeostasis. GW501516 binds and activates this receptor with high selectivity relative to PPARα and PPARγ in laboratory assays. Activation alters expression of target genes in skeletal muscle, liver, and adipose tissue in animal models. The exact clinical consequences of these changes in humans remain incompletely characterized, and observed effects in animals do not establish therapeutic benefit or safety.
Stability of GW501516 depends on form, temperature, light exposure, and moisture. Solid reference material is typically stored frozen or refrigerated in a desiccator and protected from light. Solutions in organic solvents such as dimethyl sulfoxide are often kept frozen in aliquots to reduce freeze-thaw cycling. Aqueous solubility is low, so aqueous stock solutions can be difficult to prepare without cosolvents. Degradation may appear as changes in chromatographic purity or mass spectral signal. Stability studies are needed to establish shelf life for any specific preparation.
Quality assessment for cardarine samples usually combines identity, purity, and impurity testing. Nuclear magnetic resonance spectroscopy and mass spectrometry can confirm molecular structure, while high-performance liquid chromatography estimates purity. Certificates of analysis from testing laboratories may list these results, but they do not establish safety or legality. In the absence of approved manufacturing, products sold online may contain the wrong compound, variable amounts, or unlisted contaminants. Independent verification is therefore central to analytical work and to interpreting any reported biological activity.
Legal status varies by country. In some places, cardarine is controlled under medicines or psychoactive substances laws; in others, it may be sold with minimal oversight as a research chemical. Customs agencies have intercepted shipments, and several national health agencies have issued warnings about products marketed for bodybuilding or performance enhancement. The lack of a standardized pharmaceutical supply means identity, purity, and contamination levels can differ widely between samples. These factors make cardarine a regulatory and public health concern rather than a conventional prescription drug.
Cardarine is a common name for GW501516, a synthetic compound first described in the 1990s as a selective agonist of the peroxisome proliferator-activated receptor delta. It was studied in preclinical models for metabolic and cardiovascular conditions, but it has not been approved as a medicine in the United States, Europe, or other major jurisdictions. Retail products labeled as cardarine are generally research chemicals or supplements, not pharmaceutical formulations. Because human safety and efficacy data remain limited, regulatory agencies treat it as an unapproved substance rather than a therapeutic product.
Early clinical research explored GW501516 for lipid disorders, obesity, and diabetes. Some short-term human studies reported changes in HDL cholesterol, LDL cholesterol, and triglycerides. The development program was discontinued after rodent studies showed dose-dependent tumor formation in multiple tissues, including liver, bladder, stomach, and skin. These findings raised concerns about long-term cancer risk in humans. Because human exposure data are limited, the clinical significance of the rodent tumors remains uncertain.
Literature on cardarine often separates receptor pharmacology from toxicology. Mechanistic papers describe PPARδ activation and gene expression changes, while safety assessments focus on carcinogenicity and species differences. Questions remain about whether rodent tumors arise through PPARδ-dependent or off-target mechanisms. Another open area is how human metabolism and exposure compare with those in animal studies. Analytical methods such as liquid chromatography–mass spectrometry are used to confirm identity in biological and product samples.
== Pathophysiology == Cerebrospinal fluid is produced by the choroid plexus in the ventricles of the brain and contained by the dura and arachnoid layers of the meninges. The brain floats in CSF, which also transports nutrients to the brain and spinal cord. As holes form in the spinal dura mater, CSF leaks out into the surrounding space. The CSF is then absorbed into the spinal epidural venous plexus or soft tissues around the spine. Due to the sterile conditions of the soft tissues around the spine, there is no risk of meningitis.
Creatine + ATP ⇌ creatine phosphate + ADP + H+ (this reaction is Mg2+-dependent) However, annelids (segmented worms) use a set of unique phosphagens; for example, earthworms use the compound lombricine. Phosphagens were discovered by Philip Eggleton and his wife Grace Eggleton.
=== Celebrity status === In 2008, Pudzianowski took part in the 7th season of Dancing with the Stars in his native Poland. He advanced to the final episode, but ultimately finished second, losing to actress Magdalena Walach. Pudzianowski was a contestant in the 1st season of the singing reality show Just the Two of Us in Poland. He was coupled with former Ich Troje singer Anna Wiśniewska.
== Benign neoplasms (210–229) == 210 Benign neoplasm of lip, oral cavity, and pharynx 211 Benign neoplasm of other parts of digestive system 211.3 Colon Familial adenomatous polyposis 212 Benign neoplasm of respiratory and intrathoracic organs 212.0 Nasal cavities middle ear and accessory sinuses 212.1 Larynx 212.2 Trachea 212.3 Bronchus and lung 212.4 Pleura 212.5 Mediastinum 212.6 Thymus 212.7 Heart Myxoma Rhabdomyoma 213 Benign neoplasm of bone and articular cartilage 213.9 Bone and articular cartilage, site unspecified Chondroma 214 Lipoma 215 Other benign neoplasm of connective and other soft tissue 216 Benign neoplasm of skin Melanocytic nevus 217 Benign neoplasm of breast 218 Uterine leiomyoma 219 Other benign neoplasm of uterus 220 Benign neoplasm of ovary 221 Benign neoplasm of other female genital organs 222 Benign neoplasm of male genital organs 223 Benign neoplasm of kidney and other urinary organs 224 Benign neoplasm of eye 225 Benign neoplasm of brain and other parts of nervous system 226 Benign neoplasm of thyroid glands 227 Benign neoplasm of other endocrine glands and related structures 228 Hemangioma and lymphangioma, any site 228.0 Hemangioma, any site 228.1 Lymphangioma, any site 229 Benign neoplasm of other and unspecified sites
Sources: en.wikipedia.org
13,802, 27 June 2008 - The SENSEX dropped by 600 points, to fall below the 14,000 mark, closing at 13,802. 12,962, 1 July 2008 - The SENSEX falls below the 13,000 mark, closing at 12,962. 11,802, 6 October 2008 - The SENSEX dropped by 724.62 points amid fears of the US recession and attempts by governments across the world to save their failing banks, to fall below the 12,000 mark, closing at 11,802. 10,527, 10 October 2008 - The SENSEX dropped by 800.51 points amid weak industrial production data and concerns over impact of global economic crisis on IT and banking firms in India, to fall below the 11,000 mark, closing at 10,527. 9,975, 17 October 2008 – The SENSEX crashes below the psychological 5-figure mark of 10,000 points, closing at 9,975.35, following extremely negative global financial indications in US and other countries. Just ten months earlier, in December 2007, SENSEX had closed above the 20,000 mark for the first time. 8,701.07, 24 October 2008 - The SENSEX lost 10.96% of its value (1070.63 points) on the intra-day trade, closing at 8,701.07, for its first close below the 9,000 mark since 14 June 2006, after RBI lowered its GDP growth forecasts on global economic concerns. The loss was the 2nd highest in terms of total points, and the 3rd highest percentage-wise, for a one-day period in the index's history. 8,509.56, 27 October 2008 - The SENSEX hit an intra-day low of 7,697.39, before closing at 8,509.56, for its lowest close since 14 November 2005.
=== Effects === As with peoples having migrated northward, those with light skin migrating toward the equator acclimatize to the much stronger solar radiation. Nature selects for less melanin when ultraviolet radiation is weak. Most people's skin darkens when exposed to UV light, giving them more protection when it is needed. This is the physiological purpose of sun tanning. Dark-skinned people, who produce more skin-protecting eumelanin, have a greater protection against sunburn and the development of melanoma, a potentially deadly form of skin cancer, as well as other health problems related to exposure to strong solar radiation, including the photodegradation of certain vitamins such as riboflavins, carotenoids, tocopherol, and folate. Melanin in the eyes, in the iris and choroid, helps protect from ultraviolet and high-frequency visible light; people with blue, green, and grey eyes are more at risk of sun-related eye problems. Furthermore, the ocular lens yellows with age, providing added protection. However, the lens also becomes more rigid with age, losing most of its accommodation—the ability to change shape to focus from far to near—a detriment due probably to protein crosslinking caused by UV exposure. Recent research suggests that melanin may serve a protective role other than photoprotection. Melanin is able to effectively chelate metal ions through its carboxylate and phenolic hydroxyl groups, often much more efficiently than the powerful chelating ligand ethylenediaminetetraacetate (EDTA).
=== Type II === A civilization capable of harnessing the energy radiated by its own large star – for example, by successfully completing a Dyson sphere or Matrioshka brain – with an energy consumption of ≈4×1033 erg/s. Lemarchand defined such civilizations as being able to harness and channel the entire radiation output of their star. The energy consumption would then be comparable to the luminosity of the Sun, ≈4×1033 erg/s" (≈4×1026 watts).
== Diagnosis == Blood and urine tests will measure levels of creatinine and uric acid to determine kidney function, an elevation of the ESR and CRP is possible. After a purine-restricted diet, another urine test will help determine whether the body is producing too much uric acid or the body isn't excreting enough uric acid. Rheumatoid factor may be present, especially in the group that is likely to develop rheumatoid arthritis. A fine needle is used to draw fluid from a joint to determine if there is any build-up of fluid. The presence of uric acid crystals in the fluid would indicate gout. In many cases there may be no specific test, and it is often a case of eliminating other conditions before getting a correct diagnosis.
The reference values vary across studies, ranging from > 25 cm/s to > 35 cm/s. Values above 35 cm/s indicate the absence of arterial disease, values below 25 cm/s indicate arterial insufficiency, and values of 25–35 cm/s are indeterminate because they are less specific (see image below). The data obtained should be correlated with the degree of erection observed. If the peak systolic velocities are normal, the final diastolic velocities should be evaluated, those above 5 cm/s being associated with venogenic ED.
Sources: en.wikipedia.org
Cardarine targets PPARδ, a nuclear receptor involved in lipid and energy metabolism. It does not bind the androgen receptor in the way SARMs do.
Most methods use liquid chromatography with tandem mass spectrometry. Urine is common in anti-doping testing, and blood or plasma may be used in research.
Typical guidance is cool, dry, dark storage, often at low temperature and with desiccant. Stability data are limited, so storage conditions should be verified for each batch or supplier.
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.