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Preclinical Findings And Safety Signals — Beginner to Advanced

By Editorial Desk · published 2026-03-19 · last reviewed 2026-05-07 · News

If you have been reading about WADA Prohibited List and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.

Last reviewed on 2026-05-07. Where a claim depends on a specific study, the study is described rather than over-claimed.

Preclinical Findings and Safety Signals

Safety concerns emerged from long-term animal studies. In rodents given the compound for extended periods, researchers found an increased incidence of certain cancers, including liver and bladder tumors. These findings contributed to the discontinuation of clinical development. Whether similar risks apply to short-term or low-level exposure in humans is not established, and controlled human safety data are limited. The relevance of high-dose rodent carcinogenicity findings to human use remains a subject of debate.

Human trials of GW501516 were small and short in duration. They examined lipid levels, glucose handling, and other metabolic markers, but the programs were halted after the animal cancer findings. No approved therapeutic product exists, and published human data are insufficient for establishing long-term safety. Reports of use for athletic performance come mainly from non-clinical settings and cannot be verified through controlled trials. Independent testing of products sold as cardarine has found inconsistent purity and labeling.

Laboratory studies indicate that GW501516 activates PPARδ, a nuclear receptor involved in fatty acid oxidation and energy metabolism. In rodent experiments, treated animals often showed increased endurance and reduced fat mass. These effects were observed under controlled conditions and do not establish safe or effective use in humans. The exact dose-response relationship in humans remains poorly characterized. Species differences in metabolism can affect how results translate across animals and people.

Identity and Regulatory Status

Clinical development stopped after rodent studies showed tumors at multiple sites. Whether those findings predict human cancer risk remains an open question, but they led sponsors to discontinue programs. Human safety data are limited to small, short-term studies that were not designed to assess cancer risk. Reported effects in those studies included changes in blood lipids, but the evidence is insufficient for medical use. Long-term consequences of nonmedical use are not well characterized. Questions about dose, duration, and individual susceptibility remain unresolved.

Cardarine is a common name for GW501516, an investigational compound developed in the 1990s for metabolic conditions. It acts as an agonist at peroxisome proliferator-activated receptor delta, a nuclear receptor involved in lipid and energy metabolism. The compound is frequently mislabeled as a selective androgen receptor modulator, or SARM, but its molecular target is different. GW501516 reached early clinical testing before development was discontinued. It has no approved therapeutic use in any country. The name cardarine is not a formal international nonproprietary name.

Regulatory treatment varies, but cardarine is not approved as a medicine. Sports authorities list GW501516 as a prohibited substance, and it is banned at all times under the World Anti-Doping Agency code. Many countries restrict sales for human consumption, while online vendors market it as a research chemical. Such products may lack purity data, and their actual contents can differ from the label. Purchasing or possessing cardarine may carry legal consequences depending on jurisdiction. The compound is not a dietary supplement ingredient in regulated markets.

Cardarine at a glance

PropertyValueNotes
Primary targetPPARδ (NR1C2)Nuclear receptor involved in lipid metabolism
Preclinical effectIncreased fatty acid oxidationObserved in rodent studies
Key safety signalTumors in rodents after long-term exposureContributed to halted clinical development
Human trial statusNo approved product; development stoppedLimited short-term metabolic data
Sport regulatory statusProhibited at all timesWADA hormone and metabolic modulators class

Regulatory Status and Detection Context

A persistent misconception is that cardarine is a fat-burning drug or a safe alternative to anabolic steroids. No approved therapeutic product exists, and human safety data are limited. The tumor findings in rodents remain a central concern in scientific reviews. Products sold online may contain inaccurate labels, impurities, or different compounds entirely, which complicates any assessment of effects. Independent testing of such products has reported frequent mislabeling. For these reasons, discussions in the literature emphasize risks and unknowns rather than benefits.

Cardarine is not approved for human therapeutic use in any major jurisdiction. It appears on the World Anti-Doping Agency Prohibited List as a PPARδ agonist within the hormone and metabolic modulators category. Sports organizations test for it because it has been detected in athlete samples and seized products. Regulatory actions against marketed research chemical versions have occurred in several countries, though enforcement varies. Availability through unregulated channels complicates oversight.

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Detection, Regulation, and Quality Context

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.

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.

Detection, Stability, and Quality

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.

Laboratory detection of GW501516 commonly uses liquid chromatography coupled with tandem mass spectrometry. The method can identify the parent compound or its metabolites in urine and blood after sample cleanup. Protein precipitation, solid-phase extraction, or enzymatic hydrolysis may precede analysis, depending on the matrix. Reference standards are required for accurate quantification and confirmation. Because the compound is not approved, testing often occurs in anti-doping, forensic, or research settings rather than routine clinical care. Results are reported with limits of detection and quantification.

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.

Reference notes

Transcriptional gene regulation process depends on many spatial and temporal factors in the nucleus such as global or local chromatin states, nucleosome positioning, TF binding, enhancer/promoter activities. Variant that alter the function of any of these biological processes may alter the gene regulation and cause phenotypic abnormality. Genetic variants that located in distal regulatory region can affect the binding motif of TFs, chromatin regulators and other distal transcriptional factors, which disturb the interaction between enhancer/silencer and its target gene.

When multiple antibodies are present, or when an antibody is directed against a high-frequency antigen, the normal antibody panel procedure may not provide a conclusive identification. In these cases, hemagglutination inhibition can be used, wherein a neutralizing substance cancels out a specific antigen. Alternatively, the plasma may be incubated with cells of known antigen profiles in order to remove a specific antibody (a process termed adsorption); or the cells can be treated with enzymes such as ficain or papain which inhibit the reactivity of some blood group antibodies and enhance others. The effect of ficain and papain on major blood group systems is as follows: Enhanced: ABO, Rh, Kidd, Lewis, P1, Ii Destroyed: Duffy (Fya and Fyb), Lutheran, MNS Unaffected: Kell People who have tested positive for an unexpected blood group antibody in the past may not exhibit a positive reaction on subsequent testing; however, if the antibody is clinically significant, they must be transfused with antigen-negative blood regardless.

Alpha-synuclein primary structure is usually divided in three distinct domains: Residues 1-60: An amphipathic N-terminal region dominated by four 11-residue repeats including the consensus sequence KTKEGV. This sequence has a structural alpha helix propensity similar to apolipoproteins-binding domains. It is a highly conserved terminal that interacts with acidic lipid membranes, and all the discovered point mutations of the SNCA gene are located within this terminal. Residues 61-95: A central hydrophobic region which includes the non-amyloid-β component (NAC) region, involved in protein aggregation. This domain is unique to alpha-synuclein among the synuclein family. Residues 96-140: a highly acidic and proline-rich region which has no distinct structural propensity. This domain plays an important role in the function, solubility and interaction of alpha-synuclein with other proteins.

=== Environmental impacts === Biopolymers can be sustainable, carbon neutral and are always renewable, because they are made from plant or animal materials which can be grown indefinitely. Since these materials come from agricultural crops, their use could create a sustainable industry. In contrast, the feedstocks for polymers derived from petrochemicals will eventually deplete. In addition, biopolymers have the potential to cut carbon emissions and reduce CO2 quantities in the atmosphere: this is because the CO2 released when they degrade can be reabsorbed by crops grown to replace them: this makes them close to carbon neutral. Almost all biopolymers are biodegradable in the natural environment: they are broken down into CO2 and water by microorganisms. These biodegradable biopolymers are also compostable: they can be put into an industrial composting process and will break down by 90% within six months. Biopolymers that do this can be marked with a 'compostable' symbol, under European Standard EN 13432 (2000). Packaging marked with this symbol can be put into industrial composting processes and will break down within six months or less. An example of a compostable polymer is PLA film under 20μm thick: films which are thicker than that do not qualify as compostable, even though they are "biodegradable". In Europe there is a home composting standard and associated logo that enables consumers to identify and dispose of packaging in their compost heap.

Non-specific active immunotherapy: generating a general immune system response using cytokines and other cell signaling molecules. Specific active immunotherapy: the generation of cell-mediated and antibody immune responses focused on specific antigens expressed by the cancer cells, typically using a vaccine platform. Active immunotherapies fall under the category of activation immunotherapies, which is a subset of immunotherapies that activate the immune system as opposed immunotherapies that suppress the immune system. Non-specific active immunotherapy is administered with the overall goal of generally eliminating malignant pathogens or cells from the host system. This treatment stimulates the immune system in a general sense, rather than specifically targeting a cell type e.g. cancer cells. Non-specific approaches aim to create a robust immune response that would lead to the eventual killing of malignant cells through immunomodulators such as cytokines.

Sources: en.wikipedia.org

Reference notes

The third major group of regulatory RNAs is called enhancer RNAs. It is not clear at present whether they are a unique category of RNAs of various lengths or constitute a distinct subset of lncRNAs. In any case, they are transcribed from enhancers, which are known regulatory sites in the DNA near genes they regulate. They up-regulate the transcription of the gene(s) under control of the enhancer from which they are transcribed.

RGD and other bioactive ligands can be presented on the surface of a biomaterial in a number of different spatial arrangements, and it has been demonstrated that these arrangements have a significant impact on cell behavior. In self-assembled monolayers, it was found that adhesion and proliferation of both human umbilical vein endothelial cells (HUVECs) and human mesenchymal stem cells (MSCs) increased as a function of RGD peptide density. These studies also showed that RGD density could change integrin expression, which has been postulated to enable control of biochemical signaling pathways. Further investigation of MSCs on self-assembled monolayers showed that modulating RGD density and the affinity of RGD for αvβ3 (through use of linear and cyclized RGD) could be used to control the differentiation of MSCs. The effect of RGD presentation on cells in 3D biomaterials, which more accurately replicate the in vivo environment, has also been evaluated. In degradable polyethylene glycol hydrogels, the length of capillary-like structures formed by HUVECs was directly proportional to the density of RGD in the hydrogel. Additionally, studies in nano-patterning have shown that, whereas an increase in global RGD density increases cell adhesion strength until saturation, an increase in local (mico/nano-scale) RGD density does not follow this trend.

== Purpose == Without trichrome staining, discerning one feature from another can be extremely difficult. Smooth muscle tissue, for example, is hard to differentiate from collagen. A trichrome stain can colour the muscle tissue red, and the collagen fibres green or blue. Liver biopsies may have fine collagen fibres between the liver cells, and the amount of collagen may be estimated based on the staining method. Trichrome methods are now used for differentiating muscle from collagen, pituitary alpha cells from beta cells, fibrin from collagen, and mitochondria in fresh frozen muscle sections, among other applications. It helps in identifying increases in collagenous tissue (i.e., fibrotic changes) such as in liver cirrhosis and distinguishing tumours arising from muscle cells and fibroblasts.

pcALCL is the second most common lymphoma in the category of Cutaneous T cell lymphoma cutaneous T cell lymphomas that includes lymphomatoid papulosis, various borderline CD30-positive cutaneous T cell lymphomas, and mycosis fungoides. The median age at diagnosis for pcALC is 61 years. The disease has a male predominance and appears to be more common in Caucasian populations. Individuals with pcALCL typically present with reddish masses that initially appear in the skin or, much less frequently, the lymph nodes or various organs. These masses are nodules or tumors that are often ulcerated, greater than 2 cm in diameter, and localized to a single site. In 20% of cases, however, they occur in multiple sites. In about 10% cases followed for many years, pcALCL presenting as skin lesions progresses to extracutaneous sites, mainly to regional draining lymph nodes. Over these same long periods, however, the disease's lesions partially regress in about 50% of cases but then relapse in about 40% of cases.

=== Bethlem myopathy 1 === (Collagen VI genes) See Bethlem myopathy 1 Clinical synopsis on OMIM: 158810 In Bethlem myopathy 1, in the calf, one of the first signs is often a 'rim' of fatty infiltration between the soleus and gastrocnemius muscles. Although there is fatty infiltration, the calf muscles do not appear pseudohypertrophic, in fact they may appear slender. In the thighs, there is also significant fatty infiltration of the vasti muscles, with a rim of fatty infiltration on the periphery of the muscles, while the center is more or less spared (characteristic "outside-in" pattern). This "outside-in" pattern distinguishes it from other myopathies known to have contractures, such as Emery-Dreifuss muscular dystrophy. The exception is the rectus femoris muscle of the thigh, where fatty infiltration occurs in the center of the muscle, but spares the periphery. This unusual pattern is described as a "central cloud" and is also a distinguishing feature, as it is not seen in the rectus femoris of LMNA-related Emery-Dreifuss myopathy. Bethlem myopathy 1 may also include neonatal-onset torticollis (neck contracture) and hypotonia ("floppy baby"), delayed motor mile stones, with respiratory difficulties potentially occurring later in life. Contractures presenting in infancy may resolve by age 2 years, but reoccur as the disease progresses, typically by late of the first decade or early teens.

Sources: en.wikipedia.org

Frequently asked questions

What did animal studies show?

Rodent studies reported increased endurance and fat oxidation after GW501516 exposure. Long-term studies also found higher rates of some tumors, which led to halted development.

Has cardarine been tested in humans?

Small short-term human trials examined metabolic markers such as lipids and glucose. The trials did not continue after rodent cancer findings, so long-term human safety is unknown.

Does cardarine improve athletic performance in people?

Controlled human trials have not established a performance benefit. Anecdotal reports exist, but they are not reliable evidence.

Is cardarine a SARM?

No. Cardarine is GW501516, a PPARδ agonist, while SARMs act on androgen receptors. The two classes are often grouped in informal discussions despite different mechanisms.

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