The short version of Investigational drug fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-01-17. Anything still debated is marked as such rather than presented as settled.
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.
Published human data are sparse and mostly come from early-phase trials. Those studies examined short-term changes in lipids, glucose, and exercise capacity, but they were not large enough to establish efficacy or long-term safety. Some animal experiments reported increased running endurance, yet such findings do not prove a performance benefit in people. Anti-doping laboratories detect GW501516 and its metabolites in urine or blood using liquid chromatography-tandem mass spectrometry. Detection windows depend on dose, sample type, and individual metabolism. The method is sensitive enough to identify trace residues in tested samples.
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.
Cardarine is a common name for the investigational chemical GW501516, also written GW-1516. It was developed as a peroxisome proliferator-activated receptor delta agonist for metabolic conditions such as dyslipidemia. Early research focused on lipid handling and energy use in skeletal muscle and other tissues. The compound was never approved as a medicine. In public discussion, it is often grouped with performance-enhancing substances, although its receptor target differs from that of anabolic steroids or selective androgen receptor modulators. Regulatory and health authorities have issued warnings about its use.
GW501516 acts on PPARδ, a nuclear receptor that helps regulate fatty acid oxidation and energy homeostasis. In animal studies, activation of this receptor was associated with increased endurance and changes in lipid metabolism. Human trials examined effects on blood lipids and other metabolic markers, but the compound did not advance to approval. Rodent studies later reported tumors in multiple tissues at doses used in those experiments. Whether those findings translate to human risk remains uncertain, and the clinical relevance of the animal data is still debated.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white solid | Typical form of reference material |
| Solubility | Low in water; soluble in DMSO | Used to prepare stock solutions |
| Typical storage | -20 °C, desiccated, protected from light | Common laboratory practice |
| Analytical method | LC-MS/MS | Detects parent compound and metabolites |
| Common test matrix | Urine or blood | Used in anti-doping analysis |
Cardarine is a common name for GW501516, a synthetic compound developed in the 1990s through research collaborations involving GlaxoSmithKline. It belongs to a class of molecules known as peroxisome proliferator-activated receptor delta agonists. Early studies explored its effects on lipid metabolism and energy expenditure in animal models. The compound was never approved as a human medicine, and clinical development was discontinued. In the years since, it has appeared in fitness and bodybuilding communities as a performance-enhancing substance. Regulatory agencies classify it as an unapproved drug.
PPARδ is a nuclear receptor that regulates gene expression related to fatty acid oxidation, glucose homeostasis, and mitochondrial function. GW501516 binds to this receptor with high affinity and activates downstream signaling in skeletal muscle and other tissues. Animal studies reported increased endurance and altered fuel preference, but human data remain limited and inconsistent. The precise relationship between receptor activation and observed physiological changes is still an area of active investigation. Researchers have also examined whether the compound affects inflammation or cell proliferation. No approved therapeutic indication exists for cardarine.
Cardarine is a synthetic compound also known as GW501516, GW-501516, and sometimes endurobol. It was developed as a selective agonist of peroxisome proliferator-activated receptor delta, a nuclear receptor involved in fatty acid oxidation and energy metabolism. The compound was studied in preclinical models for metabolic and cardiovascular conditions, but it did not become a marketed human medicine. In regulatory and anti-doping contexts, it is treated as a prohibited substance rather than a licensed medicine.
The pharmacological interest in cardarine centers on PPARδ activation and its downstream effects on lipid handling and mitochondrial function. In animal studies, PPARδ agonists have been associated with changes in exercise endurance and fatty acid utilization, though results vary by model and protocol. Human data remain sparse, and the absence of large controlled trials limits conclusions about efficacy. Researchers often describe the compound as a tool for probing PPARδ biology rather than a proven therapeutic agent.
Preclinical research reported that GW501516 increased running endurance in mice and improved lipid profiles in some animal species. Early human trials explored effects on high-density lipoprotein cholesterol, triglycerides, and glucose handling, but the program was discontinued. Published human data are sparse and do not establish efficacy for any condition. Studies also examined PPAR delta in cancer biology, with conflicting findings across models. The relationship between receptor activation, tissue context, and disease risk remains an active area of investigation.
Anti-doping laboratories identify GW501516 and its metabolites using liquid chromatography-tandem mass spectrometry. Urine is the usual matrix, and detection can occur after the parent compound has cleared from blood. The exact detection window depends on dose, formulation, individual metabolism, and assay sensitivity. Because the compound is prohibited at all times, athletes are subject to testing in and out of competition. Analytical methods continue to improve as new metabolites and designer analogs are characterized.
=== Intrinsic sympathomimetic activity === Also referred to as intrinsic sympathomimetic effect, this term is used particularly with beta blockers that can show both agonism and antagonism at a given beta receptor, depending on the concentration of the agent (beta blocker) and the concentration of the antagonized agent (usually an endogenous compound, such as norepinephrine). See partial agonist for a more general description. Some beta blockers (e.g. oxprenolol, pindolol, penbutolol, labetalol and acebutolol) exhibit intrinsic sympathomimetic activity (ISA). These agents are capable of exerting low-level agonist activity at the β-adrenergic receptor while simultaneously acting as a receptor site antagonist. These agents, therefore, may be useful in individuals exhibiting excessive bradycardia with sustained beta blocker therapy. Agents with ISA should not be used for patients with any kind of angina as it can aggravate or after myocardial infarctions. They may also be less effective than other beta blockers in the management of angina and tachyarrhythmia.
The compound is now under active investigation by researchers at NIMH for potential clinical use, and it is hoped that use of HNK instead will mitigate the various concerns (such as abuse and dissociation) of using ketamine itself in the treatment of depression.
Refeeding syndrome (RFS) is a metabolic disturbance which occurs as a result of reinstitution of nutrition in people and animals who are starved, severely malnourished, or metabolically stressed because of severe illness. When too much food or liquid nutrition supplement is eaten during the initial four to seven days following a malnutrition event, the production of glycogen, fat and protein in cells may cause low serum concentrations of potassium, magnesium and phosphate. The electrolyte imbalance may cause neurologic, pulmonary, cardiac, neuromuscular, and hematologic symptoms—many of which, if severe enough, may result in death. Refeeding syndrome can occur when someone who has not eaten for a long time, starts eating normal or even binging amounts of food. Individuals with drug abuse who begin to reintroduce normal eating habits after a period of malnutrition may be at increased risk for refeeding syndrome.
Sources: en.wikipedia.org
4-Hydroxymandelate is subsequently oxidized by hydroxymandelate oxidase (Hmo) to 4-hydroxylbenzoylformate, using FMN as a cofactor. Finally, 4-hydroxyphenylglycine transaminase (HpgT) transfers an ammonia moiety from a donor to 4-hydroxylbenzoylformate to form HPG. Several different molecules can serve as the nitrogen donor for the transamination, however, Hubbard et al suspect L-tyrosine to serve as the most efficient donor. By doing so, the following cycle is constructed:
In addition to actions at receptors, Semax, as well as a related peptide drug, Selank, have been found to inhibit enzymes involved in the degradation of enkephalins and other endogenous regulatory peptides (IC50 = 10 μM), though the clinical significance of this property is uncertain. As a peptide, Semax has poor oral bioavailability and hence is administered parenterally as a nasal spray or subcutaneous injection.
== Other animals == Inactivity and starvation in mammals lead to atrophy of skeletal muscle, accompanied by a smaller number and size of the muscle cells as well as lower protein content. In humans, prolonged periods of immobilization, as in the cases of bed rest or astronauts flying in space, are known to result in muscle weakening and atrophy. Such consequences are also noted in small hibernating mammals like the golden-mantled ground squirrels and brown bats. A striking example of human-induced atrophy is seen in Amar Bharati, an Indian sadhu who held his arm raised for decades as a spiritual devotion, resulting in severe muscle atrophy and loss of function in the limb. Bears are an exception to this rule; species in the family Ursidae are famous for their ability to survive unfavorable environmental conditions of low temperatures and limited nutrition availability during winter by means of hibernation. During that time, bears go through a series of physiological, morphological, and behavioral changes. Their ability to maintain skeletal muscle number and size during disuse is of significant importance. During hibernation, bears spend 4–7 months of inactivity and anorexia without undergoing muscle atrophy and protein loss. A few known factors contribute to the sustaining of muscle tissue. During the summer, bears take advantage of the nutrition availability and accumulate muscle protein. The protein balance at time of dormancy is also maintained by lower levels of protein breakdown during the winter.
Sources: en.wikipedia.org
=== Research === AM-1006 – undefined mechanism of action (short-acting subperceptual psychoactive drug) – substance use disorders EQL-101 – undefined mechanism of action (non-hallucinogenic non-cardiotoxic ibogaine derivative) – substance use disorders – Equulus Therapeutics Ibogaine – various actions, oneirogen/hallucinogen – substance-related disorders Mebufotenin (5-MeO-DMT; LSR-2000) – non-selective serotonin receptor agonist, serotonin 5-HT1A and 5-HT2A receptor agonist, serotonergic psychedelic – alcoholism MYCO-004 (patch-delivered tryptamine compound) – undefined mechanism of action, serotonergic psychedelic – smoking withdrawal, substance-related disorders Research programme: Ibogaine derivatives - MindMed/Nextage Therapeutics – various actions – opioid-related disorders Research programme: monoclonal antibody therapeutics - CounterX Therapeutics – undefined mechanism of action – opioid-related disorders Research programme: psychedelic and empathogenic compounds subcutaneous - Bexson Biomedical – undefined mechanism of action – substance-related disorders Substance-related disorders therapeutics - Tessara Therapeutics/Xylo Bio/University of Sydney – neuronal plasticity modulators – substance-related disorders VVZ-2471 – metabotropic glutamate mGlu5 receptor antagonist, serotonin 5-HT2A receptor antagonist – opioid-related disorders
The district's arterial roads are laid out on a grid system of north–south and east–west, corresponding to the concession roads of the original township, laid out to facilitate the establishment of farming communities. Kingston Road and Danforth Avenue were laid out prior to surveying the township, and both run diagonally in a southwest–northeast direction across the south end of Scarborough. From north to south, the major east–west arterial roads are Steeles Avenue, Finch Avenue, Sheppard Avenue, Ellesmere Road, Lawrence Avenue, Eglinton Avenue and St. Clair Avenue. From west to east, the major north–south arterial roads are Victoria Park Avenue, Pharmacy Avenue, Warden Avenue, Birchmount Road, Kennedy Road, Midland Avenue, Brimley Road, McCowan Road, Bellamy Road North, Markham Road, Scarborough Golf Club Road, Neilson Road, Morningside Avenue, Meadowvale Road and Port Union Road. Kingston Road was formerly Ontario Highway 2, and was the main highway through the district until the building of Highway 401, which runs east–west across the district, with six to eight lanes in each direction. The short, minor freeway Highway 2A runs parallel to Lake Ontario in the eastern part of Scarborough.
According to the Sustainable Development Goals Index 2021, 10.35% of the population of Jammu and Kashmir live below the national poverty line, the third-highest among union territories in the country.
Sources: en.wikipedia.org
Anti-doping and clinical laboratories commonly use liquid chromatography-tandem mass spectrometry. The method can identify GW501516 and its metabolites in urine or blood. Detection depends on sample timing and the amount present.
PPARδ is a nuclear receptor that regulates genes linked to fatty acid oxidation and energy metabolism. Activation can alter lipid handling and energy use in experimental models. The full range of effects in humans is still under study.
The solid compound is generally stable when kept cold, dry, and protected from light. Solutions may degrade faster, so laboratory protocols often specify fresh preparation or cold storage. Stability can depend on solvent, concentration, and container.
No. Cardarine is a PPARδ agonist, while selective androgen receptor modulators act on androgen receptors. The two classes differ in receptor target and downstream effects.