preclinical models 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.
Last reviewed on 2025-09-13. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
GW501516 acts as an agonist at peroxisome proliferator-activated receptor delta, a nuclear receptor involved in transcription of genes related to lipid handling and energy use. Activation of PPARδ can shift skeletal muscle toward greater fatty acid oxidation in animal models, which is one reason it drew interest for metabolic disease and exercise research. The exact downstream effects depend on tissue, species, dose, and duration. Human data are sparse, so many proposed benefits remain hypotheses rather than established clinical outcomes.
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.
Sporting authorities added GW501516 to prohibited lists after it appeared in athlete samples and online markets. The World Anti-Doping Agency classifies it as a hormone and metabolic modulator, and its use can lead to an anti-doping rule violation. Some early laboratory work suggested effects on fatty acid oxidation and endurance-related metabolism in animals, but those findings do not establish safe or effective use in people. Reports of adverse events in humans are scarce and often anecdotal, which complicates risk assessment.
| Property | Value | Notes |
|---|---|---|
| Solubility | Soluble in dimethyl sulfoxide and some organic solvents; practically insoluble in water | Solvent choice affects laboratory handling |
| Typical storage | -20 °C, desiccated, protected from light | Common condition for research samples |
| Analytical method | Liquid chromatography–tandem mass spectrometry (LC-MS/MS) | Used for identification and quantification in biological or product samples |
| Common synonyms | GW501516, GW-501516, GSK-516, Endurobol | Names found in research and anti-doping literature |
| Regulatory status | Unapproved therapeutic; prohibited in competitive sport | Status can vary by country and context |
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.
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.
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.
Cardarine is the common name for GW501516, a synthetic compound studied as a peroxisome proliferator-activated receptor delta agonist. Researchers developed it to explore treatments for lipid disorders and metabolic conditions. It is not an approved medicine in any country. Early clinical work examined changes in HDL cholesterol and triglycerides, but development was discontinued after animal studies raised concerns about cancer. The compound remains available as a research chemical and appears in discussions of performance enhancement.
At the molecular level, GW501516 binds and activates PPARδ, a nuclear receptor that regulates transcription. Activation shifts expression of genes involved in fatty acid oxidation, energy expenditure, and lipid transport in skeletal muscle and liver. Animal studies report increased endurance and altered lipid profiles after exposure. Human data are limited to small trials and do not establish long-term safety or efficacy. PPARδ also has roles in cell proliferation, so the relationship between activation and cancer risk remains an open question.
Apryll Marie Stalcup is an American chemist who is Professor and was the Director of the Irish Separation Science Cluster at Dublin City University. She was awarded the 2021 Chromatography Forum of the Delaware Valley Stephen Dal Nogare Award, the 2015 American Microchemical Society Benedetti Pichler Award and named in the 2016 Power List of the Top 50 Women Analytical Scientists worldwide. Her research considers surface-confined ionic liquids and chiral separations.
PABA is an intermediate in the synthesis of folate by bacteria, plants, and fungi. Many bacteria, including those found in the human intestinal tract such as E. coli, generate PABA from chorismate by the combined action of the enzymes 4-amino-4-deoxychorismate synthase and 4-amino-4-deoxychorismate lyase. Plants produce PABA in their chloroplasts, and store it as a glucose ester (pABA-Glc) in their tissues. The malarial protozoan Plasmodium only make PABA when necessary, preferring to get it from the surroundings if able to. Some bacteria, including a few found in the human microbiome, are unable to make PABA for themselves but can use PABA to make folate. A few are very efficient at the PABA-to-folate conversion despite not making their own PABA. Sulfonamide drugs are structurally similar to PABA, and their antibacterial activity is due to their ability to interfere with the conversion of PABA to folate by the enzyme dihydropteroate synthetase. Thus, bacterial growth is limited through folate deficiency.
Amylin, or islet amyloid polypeptide (IAPP), is a 37-residue peptide hormone. It is co-secreted with insulin from the pancreatic β-cells in the ratio of approximately 100:1 (insulin:amylin). Amylin plays a role in glycemic regulation by slowing gastric emptying and promoting satiety, thereby preventing spikes in blood glucose levels after a meal. IAPP is processed from an 89-residue coding sequence. Proislet amyloid polypeptide (proIAPP, proamylin, proislet protein) is produced in the pancreatic beta cells (β-cells) as a 67 amino acid, 7404 Dalton pro-peptide and undergoes post-translational modifications including protease cleavage to produce amylin.
In 1961, Peter Mitchell proposed chemiosmosis as a cell's primary system of energy conversion. The mechanism, now ubiquitous in living cells, powers energy conversion in micro-organisms and in the mitochondria of eukaryotes, making it a likely candidate for early life. Mitochondria produce adenosine triphosphate (ATP), the energy currency of the cell used to drive cellular processes such as chemical syntheses. The mechanism of ATP synthesis involves a closed membrane in which the ATP synthase enzyme is embedded. The energy required to release strongly bound ATP has its origin in protons that move across the membrane. In modern cells, those proton movements are caused by the pumping of ions across the membrane, maintaining an electrochemical gradient. In the first organisms, the gradient could have been provided by the difference in chemical composition between the flow from a hydrothermal vent and the surrounding seawater, or perhaps meteoric quinones that were conducive to the development of chemiosmotic energy across lipid membranes if at a terrestrial origin.
Vaginal films are soluble, thin sheets of medication that are inserted into the vagina where they dissolve and release the substances. Typical uses include delivery of contraceptive substances or antibiotics for infections. These films are inserted by simply pushing them into the vagina with one’s fingers. There they dissolve quickly upon interaction with natural vaginal fluids. Bioadhesives are substances that naturally stick to live tissue. Currently, studies are being done on bioadhesives adhering to cervical mucous membranes to allow for an extended release period. The drug would be released with mucus to create a localized treatment with high effectiveness. This is anticipated to be highly useful for treatment of cervical cancer. Bioadhesives can come in multiple forms, such as films, tablets, or gels. The appeal of bioadhesives is that they take advantage of the mucous environment surrounding the cervix and utilize it to benefit the drug delivery mechanism.
Sources: en.wikipedia.org
Mouse MA-10 cells respond to 5-oxo-ETE but lack OXER1. It has been suggested that these cells' responses to 5-oxo-ETE are mediated by an ortholog to OXER1, mouse niacin receptor 1, Niacr1, which is a G protein-coupled receptor for niacin, or, alternatively, by one or more of the mouse hydroxycarboxylic acid (HCA) family of the G protein-coupled receptors, HCA1 (GPR81), HCA2 (GPR109A), and HCA3 (GPR109B), which are G protein-coupled receptors for fatty acids.
Binding curves describe the binding behavior of ligand to a protein. Curves can be characterized by their shape, sigmoidal or hyperbolic, which reflect whether or not the protein exhibits cooperative or noncooperative binding behavior respectively. Typically, the x-axis describes the concentration of ligand and the y-axis describes the fractional saturation of ligands bound to all available binding sites. The Michaelis Menten equation is usually used when determining the shape of the curve. The Michaelis Menten equation is derived based on steady-state conditions and accounts for the enzyme reactions taking place in a solution. However, when the reaction takes place while the enzyme is bound to a substrate, the kinetics play out differently. Modeling with binding curves are useful when evaluating the binding affinities of oxygen to hemoglobin and myoglobin in the blood. Hemoglobin, which has four heme groups, exhibits cooperative binding. This means that the binding of oxygen to a heme group on hemoglobin induces a favorable conformation change that allows for increased binding favorability of oxygen for the next heme groups. In these circumstances, the binding curve of hemoglobin will be sigmoidal due to its increased binding favorability for oxygen. Since myoglobin has only one heme group, it exhibits noncooperative binding which is hyperbolic on a binding curve.
Bacterial display (or bacteria display or bacterial surface display) is a protein engineering technique used for in vitro protein evolution. Libraries of polypeptides displayed on the surface of bacteria can be screened using flow cytometry or iterative selection procedures (biopanning). This protein engineering technique allows us to link the function of a protein with the gene that encodes it. Bacterial display can be used to find target proteins with desired properties and can be used to make affinity ligands which are cell-specific. This system can be used in many applications including the creation of novel vaccines, the identification of enzyme substrates and finding the affinity of a ligand for its target protein. Bacterial display is often coupled with magnetic-activated cell sorting (MACS) or fluorescence-activated cell sorting (FACS) techniques. Competing methods for protein evolution in vitro are phage display, ribosome display, yeast display, and mRNA display. Bacteriophage display is the most common type of display system used although bacterial display is becoming increasingly popular as technical challenges are overcome. Bacterial display combined with FACS also has the advantage that it is a real-time technique.
A property of DNA is its ability to re-anneal into double-stranded molecules when pH conditions are neutralized. Under neutral conditions, hydrogen bonds reform between complementary base pairs. Because the plasmid was so tightly coiled and small before the alkaline conditions were established, it can easily re-anneal. The chromosomal DNA, however, because of its lengthy strands, does not re-anneal. Once the plasmid DNA reassociates into double-stranded molecules, it dissolves into the solution. Potassium acetate reacts with the SDS detergent, magnesium ions, and calcium ions already present in the solution and forms potassium dodecyl sulfate (KDS), an insoluble white solid which precipitates out of solution. The remaining chromosomal DNA strands, denatured proteins, and added chemicals stick together and precipitate out with the KDS. The plasmid DNA, however, remains dissolved in the liquid solution. The solution is usually centrifuged to collect the insoluble precipitates into a debris pellet at the bottom of the sample tube and thereby isolate them from the supernatant.
AlphaKnot is a scientific database and web server for detecting, classifying, and visualizing protein knots and other forms of protein-chain entanglement. It was developed to facilitate the analysis of protein structures predicted by AlphaFold and other machine-learning methods, but can also be used to analyze experimentally determined structures. The current version, AlphaKnot 2.0, combines two closely related components: a precomputed database containing proteins identified as knotted in large-scale structure-prediction datasets, and an analysis server that allows users to investigate the topology of individual protein structures in greater detail.
Sources: en.wikipedia.org
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.
No. It is not an anabolic-androgenic steroid; it is a synthetic PPARδ agonist. Because it is banned in sport, it is sometimes grouped with doping agents even though its chemical class differs from steroids.
Human data are limited and development was discontinued, so major effects and long-term risks are not well characterized. Some early studies examined metabolic markers, but they do not provide a basis for unsupervised use.
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.