A practical reference on unapproved substance: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-09-12. Anything still debated is marked as such rather than presented as settled.
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.
Laboratory studies have examined GW501516 in cell cultures and rodents for conditions such as dyslipidemia, insulin resistance, and obesity. Some trials in humans were initiated, but development was discontinued after preclinical findings raised concerns about cancer in certain models. Those findings do not prove that the compound causes cancer in people, but they contributed to regulatory caution. Later reviews often describe the evidence as preliminary and insufficient for assessing long-term safety.
In the fitness and bodybuilding literature, cardarine is frequently discussed as an endurance agent or fat-loss compound, although such claims are not supported by robust clinical evidence. Online descriptions often mix animal data, user anecdotes, and marketing language. Researchers who study PPARδ agonists distinguish between receptor activation in controlled experiments and unsupervised use of unverified products. The latter introduces unknown purity, dose, and interactions, making reported experiences difficult to interpret scientifically.
| Property | Value | Notes |
|---|---|---|
| IUPAC name | {4-[({4-methyl-2-[4-(trifluoromethyl)phenyl]-1,3-thiazol-5-yl}methyl)sulfanyl]phenoxy}acetic acid | Systematic name for GW501516 |
| CAS Registry Number | 317318-70-0 | Unique identifier for the parent compound |
| Molecular formula | C21H18F3NO3S2 | Includes carbon, hydrogen, fluorine, nitrogen, oxygen, and sulfur |
| Molecular weight | 453.5 g/mol | Approximate value for the neutral form |
| Appearance | White to off-white powder | Typical description for purified laboratory material |
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.
Regulatory treatment of cardarine differs by context and jurisdiction. In competitive sport, the World Anti-Doping Agency lists PPARδ agonists, including GW501516, as prohibited at all times. Outside sport, it lacks approval as a prescription medicine in major drug markets, and products sold for human consumption may be treated as unapproved drugs. Some countries also restrict importation or sale through general consumer protection and medicines laws. These classifications affect availability, testing, and legal risk without establishing therapeutic value.
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.
Handling and quality assessment of cardarine reference material follow general laboratory practices for poorly characterized compounds. It typically appears as a white to off-white powder and is sparingly soluble in water but soluble in organic solvents such as dimethyl sulfoxide and ethanol. Storage recommendations usually specify a cool, dry, dark place, with long-term storage at low temperature and desiccation. Purity may be checked by high-performance liquid chromatography with ultraviolet detection, while identity is confirmed by mass spectrometry and nuclear magnetic resonance. No pharmacopeial monograph exists, so reported purity and stability depend on the supplier’s methods.
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.
Activation of PPARδ changes transcription of genes involved in fatty acid transport, mitochondrial function, and skeletal muscle fuel preference. In rodent studies, pharmacological PPARδ activation was associated with increased endurance and altered body composition. These findings generated interest in performance enhancement, but species differences and study designs limit direct extrapolation to humans. Small human trials were conducted in the 2000s and later discontinued. The extent to which cardarine produces similar metabolic or performance effects in people remains an open question.
The compound is typically described as a laboratory compound rather than a therapeutic product. Published reports have explored its role in lipid disorders, insulin sensitivity, and exercise metabolism, yet no major drug regulator has approved it for medical use. Commercial samples sold under the cardarine name may vary in purity and identity. Analytical confirmation is therefore necessary when the material is discussed in scientific or regulatory contexts. Its classification as a prohibited substance in sport further shapes how it is studied and reported.
=== Blood symptoms === The characteristic hematological (blood) effects of copper deficiency are anemia (which may be microcytic, normocytic or macrocytic) and neutropenia. Thrombocytopenia (low blood platelets) is unusual. The peripheral blood and bone marrow aspirate findings in copper deficiency can mimic myelodysplastic syndrome. Bone marrow aspirate in both conditions may show dysplasia of blood cell precursors and the presence of ring sideroblasts (erythroblasts containing multiple iron granules around the nucleus). Unlike most cases of myelodysplastic syndrome, the bone marrow aspirate in copper deficiency characteristically shows cytoplasmic vacuoles within red and white cell precursors, and karyotyping in cases of copper deficiency does not reveal cytogenetic features characteristic of myelodysplastic syndrome. Anemia and neutropenia typically resolve within six weeks of copper replacement.
==== Lamarckian inheritance ==== Similarly, his experiments with Wilfred Eade Agar to test William McDougall's supposed demonstration of Lamarckian inheritance of training in rats were negative and showed the inadequacy of McDougall's controls, the first results being published in 1935.
One study of an elderly Japanese population found correlations between the MTHFR 677CT mutation, an Apo E polymorphism, and certain types of senile dementia. Other research has found that individuals with folate-related mutations can still have a functional deficiency even when blood levels of folate are within the normal range, and recommended supplementation of methyltetrahydrofolate to potentially prevent and treat dementia (along with depression). A 2011 study from China also found that the C677T SNP was associated with Alzheimer's disease in Asian populations (though not in Caucasians). C677T polymorphism is associated with risk of myocardial infarction in African, North American, and elderly populations. The CDC provides a web page with information on the "MTHFR Gene, Folic Acid, and Preventing Neural Tube Defects". National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention. 27 May 2025. Retrieved 6 Jun 2025.
Negative ions are formed by resonance capture of a near-thermal energy electron, dissociative capture of a low energy electron and via ion-molecular interactions such as proton transfer, charge transfer and hydride transfer. Compared to the other methods involving negative ion techniques, NCI is quite advantageous, as the reactivity of anions can be monitored in the absence of a solvent. Electron affinities and energies of low-lying valencies can be determined by this technique as well.
Sources: en.wikipedia.org
L-tyrosine → para-tyramine or L-DOPA → Dopamine L-tyrosine → L-DOPA → 3,4-dihydroxyphenylacetaldehyde (DOPAL) Dopamine + DOPAL → (S)-norlaudanosoline →→→ (S)-reticuline → 1,2-dehydroreticulinium → (R)-reticuline → salutaridine → salutaridinol → thebaine → neopinone → codeinone → codeine → morphine The intermediate (S)-norlaudanosoline (also known as tetrahydropapaveroline) is synthesized through the addition of DOPAL and dopamine. CYP2D6, a cytochrome P450 isoenzyme is involved in two steps along the biosynthetic pathway, catalyzing both the biosynthesis of dopamine from tyramine and of morphine from codeine. Urinary concentrations of endogenous codeine and morphine have been found to significantly increase in individuals taking L-DOPA for the treatment of Parkinson's disease.
Luisa DiPietro is a faculty member at the University of Illinois at Chicago College of Dentistry. She is Director of the Center for Wound Repair and Tissue Regeneration and a Professor of Periodontics for the College. DiPietro's interests in wound healing focus on the effects of aging and inflammation on scarring during healing. She investigates critical differences in inflammation and angiogenesis between oral versus cutaneous wounds that ultimately result in rapid, nonscarring healing in mucosa. From 2010 to 2011, she served as the president of the Wound Healing Society. In 2015, she was named a University Scholar of the University of Illinois. DiPietro received her PhD in immunology and DDS from the University of Illinois at Chicago.
== Clinical significance == Recessive mutations in NADK2 cause NADK2 deficiency, an inherited metabolic disorder characterized by neurological symptoms including hypotonia, developmental delay, ataxia, and encephalopathy. Affected individuals also show metabolic abnormalities, including hyperlysinemia and impaired fat oxidation with elevated C10:2-carnitine levels, consistent with secondary 2,4-dienoyl-CoA reductase deficiency. Cancer cells are exposed to elevated oxidative stress and are consequently highly dependent on mitochondrial NADPH to maintain redox homeostasis. NADK2 is essential for mitochondrial NADPH production and has therefore been proposed as a potential target to increase oxidative stress and sensitize cancer cells to apoptosis. A lack of NADK2 additionally impairs proline biosynthesis, rendering cancer cells dependent on exogenous proline for proliferation. NADK2 has been linked to Alzheimer's disease. Tau oligomers upregulate NADK2 in human neurons, leading to increased mitochondrial NADPH production, which in turn increases LRP1 expression and promotes tau uptake, creating a self-reinforcing cycle.
Some cytosolic proteins are recruited to different cellular membranes by recognizing certain types of lipid found within a given membrane. Binding of a protein to a specific lipid occurs via specific membrane-targeting structural domains that occur within the protein and have specific binding pockets for the lipid head groups of the lipids to which they bind. This is a typical biochemical protein–ligand interaction, and is stabilized by the formation of intermolecular hydrogen bonds, van der Waals interactions, and hydrophobic interactions between the protein and lipid ligand. Such complexes are also stabilized by the formation of ionic bridges between the aspartate or glutamate residues of the protein and lipid phosphates via intervening calcium ions (Ca2+). Such ionic bridges can occur and are stable when ions (such as Ca2+) are already bound to a protein in solution, prior to lipid binding. The formation of ionic bridges is seen in the protein–lipid interaction between both protein C2 type domains and annexins..
=== Rediscovery of glucagon === The hormone glucagon was discovered by C.P. Kimball and John R. Murlin in 1923 as a hyperglycaemic (blood-sugar elevating) substance among the pancreatic extracts. The biological importance of glucagon was not known and the name itself was essentially forgotten. It was a still a mystery at the time de Duve joined Bouckaert at Leuven University to work on insulin. Since 1921, insulin was the first commercial hormonal drug originally produced by the Eli Lilly and Company, but their extraction methods introduced an impurity that caused mild hyperglycaemia, the very opposite of what was expected or desired. In May 1944 de Duve realised that crystallisation could remove the impurity. He demonstrated that Lilly's insulin process was contaminated, showing that, when injected into rats, the Lilly insulin caused initial hyperglycaemia and the Danish Novo insulin did not. Following his research published in 1947, Lilly upgraded its methods to eliminate the impurity. By then de Duve had joined Carl Cori and Gerty Cori at Washington University in St. Louis, where he worked with a fellow researcher Earl Wilbur Sutherland, Jr., who later won the Nobel Prize in Physiology or Medicine in 1971. Sutherland had been working on the puzzle of the insulin-impurity substance, which he had named hyperglycemic-glycogenolytic (HG) factor. He and de Duve soon discovered that the HG factor was synthesised not only by the pancreas but also by the gastric mucosa and certain other parts of the digestive tract.
Sources: en.wikipedia.org
No. Major drug regulators have not approved GW501516 for treating any medical condition. Products sold as cardarine are typically unapproved research chemicals or supplements, so their contents and safety are not assured.
It is prohibited by the World Anti-Doping Agency as a hormone and metabolic modulator. Athletes who test positive for GW501516 can face sanctions, including suspensions and loss of results.
Cardarine is a common or trade-style name, while GW501516 is the research code for the same chemical entity. Some sources also use Endurobol or GSK-516. The names refer to the same compound, not distinct drugs.
It binds and activates PPARδ, a nuclear receptor that influences gene expression related to fatty acid metabolism and energy balance. This mechanism has been studied mainly in animals and cell models, not established as a safe human therapy.