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Background And Research Context — Reference Sheet

By Editorial Desk · published 2025-12-30 · last reviewed 2026-01-29 · Blog

GW501516 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.

Last reviewed on 2026-01-29. Where a claim depends on a specific study, the study is described rather than over-claimed.

Background and Research Context

In laboratory settings, cardarine is studied as a tool compound for probing PPARδ biology. Published experiments often use cell cultures, rodent models, or isolated tissues. Some investigations focus on metabolic effects, while others assess potential risks such as carcinogenicity observed in long-term animal studies. Because human trials are sparse, most knowledge comes from preclinical work and adverse event reports. Scientific literature frequently notes the gap between animal findings and human outcomes. The compound is not a dietary supplement and is not intended for human consumption.

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.

Background and Regulatory History

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.

Regulatory bodies treat GW501516 as a prohibited substance in competitive sport. The World Anti-Doping Agency added it to the prohibited list, and it falls under classes covering metabolic modulators and hormone-related agents. It is not approved by drug regulators for human use, and it is not a lawful dietary supplement. Products sold under the cardarine name may contain unlisted ingredients or different compounds. Because no approved product exists, quality and identity are not guaranteed by pharmaceutical manufacturing standards.

Cardarine at a glance

PropertyValueNotes
CAS Registry Number317318-70-0Unique identifier for the compound.
Chemical classPPARδ agonistSynthetic ligand for peroxisome proliferator-activated receptor delta.
AppearanceWhite to off-white solidTypical form of research-grade material.
SolubilitySoluble in DMSO and ethanolPoorly soluble in water.
Typical storage-20°CRecommended for long-term storage of stock solutions.

Mechanism and Laboratory Detection

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.

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.

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Regulation and Analytical Detection

Anti-doping laboratories detect GW501516 and its metabolites using liquid chromatography-tandem mass spectrometry. Urine is the most common matrix, though blood and dried blood spots may also be used in some programs. Detection depends on factors such as dose, timing, metabolism, and the sensitivity of the assay. Published methods describe limits of detection in the low nanogram per milliliter range for related compounds. Exact detection windows are not fixed for all situations and remain an area of ongoing study.

Products sold as cardarine have been found to contain incorrect compounds, variable amounts, or no active ingredient at all. Independent testing is required to verify identity and purity. Common analytical approaches include high-performance liquid chromatography, mass spectrometry, and nuclear magnetic resonance for structural confirmation. These methods can distinguish GW501516 from related PPAR agonists and from unrelated steroids. For regulators and researchers, such verification is central to interpreting both biological results and adverse event reports.

Mechanism and Detection Methods

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.

Identity and Pharmacological Classification

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.

Background from the literature

Nucleases are enzymes that cut DNA strands by catalyzing the hydrolysis of the phosphodiester bonds. Nucleases that hydrolyse nucleotides from the ends of DNA strands are called exonucleases, while endonucleases cut within strands. The most frequently used nucleases in molecular biology are the restriction endonucleases, which cut DNA at specific sequences. For instance, the EcoRV enzyme shown to the left recognizes the 6-base sequence 5′-GATATC-3′ and makes a cut at the horizontal line. In nature, these enzymes protect bacteria against phage infection by digesting the phage DNA when it enters the bacterial cell, acting as part of the restriction modification system. In technology, these sequence-specific nucleases are used in molecular cloning and DNA fingerprinting. Enzymes called DNA ligases can rejoin cut or broken DNA strands. Ligases are particularly important in lagging strand DNA replication, as they join the short segments of DNA produced at the replication fork into a complete copy of the DNA template. They are also used in DNA repair and genetic recombination.

On-line mass spectrometry was develop to solve some of the limitations and problem that develop from off-line analysis, such as evaporation and chemical reactions of particles in the filters during long analysis time. On-line Mass spectrometry solves these problems through the collection and analysis of aerosol particles in real time. On-line instruments are very portable and allow for spatial variability to be examined. These portable instruments can be put on many different platforms such as boats, planes, and mobile platforms (e.g. car trailers). An example of this is in the picture at the beginning with the instrumentation attached to an aircraft. Like off-line, on-line mass spectrometry has many different type of instruments, which can be broken up into two types; instruments that measures the chemistry of the particle ensemble (bulk measurement) and those that measure the chemistry of individual particles (single-particle measurement). Thus based on analytical need different instrumentation is used in analysis of the aerosol particles.

Gelita AG is a manufacturer of gelatin and collagen peptides for the food, health and nutrition, pharmaceutical industries and for several technical applications. It is headquartered in Eberbach, Germany. Founded in 1875, Gelita operates 21 production sites and 4 offices in North America, South America, Europe, South Africa, Asia, Australia and New Zealand. The plant in Sergeant Bluff, Iowa, is the largest gelatin factory in the world.

In the extracellular space in tissues, type III collagen monomers assemble into macromolecular fibrils, which aggregate into fibers, providing a strong support structure for tissues requiring tensile strength. The triple-helical conformation, which is a characteristic feature of all fibrillar collagens, is possible because of the presence of glycine as every third amino acid in the sequence of about 1000 amino acids. When the right-handed super-helix is formed, the glycine residues of each of the monomers are positioned at the center of the super-helix (where the three monomers "touch"). Each left-handed helix is characterized by a complete turn in about 3.3 amino acids. The periodicity induced by the glycines at non-integer spacing results in a super-helix that completes one turn in about 20 amino acids. This (Gly-X-Y)n sequence is repeated 343 times in the type III collagen molecule. Proline or hydroxyproline is often found in the X- and Y-position giving the triple helix stability. Several fragments of human type III collagen have been solved by X-ray crystallography, including the C-terminal propeptide trimer that governs chain selection during procollagen assembly and a cystine-knot-containing triple-helical peptide near the C-terminus, which was found to adopt both 7/2 and 10/3 triple-helical symmetries. Full-length fibrillar collagen has not been crystallized because of its length and flexibility.

Sources: en.wikipedia.org

Further detail

In recent years, diode array UV-Vis detectors have been increasingly used to collect entire spectra at any given moment of data collection. Diode array detectors (DADs) collect entire UV spectra at every point of the eluting peaks while operating as a multi-wavelength UV-Vis detector. This way they give additional information, which help understand more about the nature of the substances appearing in the chromatogram and allow their identification. DADs are the preferred detectors for HPLC method development because they facilitate better peak identification.

25499Es + 4820Ca → 302119Uue* → no atoms It is highly unlikely that this reaction will be able to create any atoms of ununennium in the near future, given the extremely difficult task of making sufficient amounts of einsteinium-254, which is favoured for production of ultraheavy elements because of its large mass, relatively long half-life of 270 days, and availability in significant amounts of several micrograms, to make a large enough target to increase the sensitivity of the experiment to the required level; einsteinium has not been found in nature and has only been produced in laboratories, and in quantities smaller than those needed for effective synthesis of superheavy elements. However, given that ununennium is only the first period 8 element on the extended periodic table, it may well be discovered in the near future through other reactions, and indeed an attempt to synthesise it is currently ongoing in Japan. Currently, none of the period 8 elements has been discovered yet, and it is also possible, due to drip instabilities, that only the lower period 8 elements, up to around element 128, are physically possible. No attempts at synthesis have been made for any heavier alkali metals: due to their extremely high atomic number, they would require new, more powerful methods and technology to make.

== Function == The main purpose of chondronectin is to allow chondrocytes and collagen II substrates to bond together. When bound, if forms a complex structure called an extracellular scaffold, which helps support the surrounding cells because of bioactive molecule diversity, which allows for chondrocytes to be anchored, mechanical forces to be bared, and maintaining physiological homeostasis. In order for chondronectin to be able to assist in binding within this complex as efficiently as possible, they must interact with a cartilage proteoglycan monomer. If there is a inhibitor that prevents synthesis of endogenous proteoglycans, along with beta-xylosides, it fully prevents chondrocytes from attaching via chondronectins. When cartilage cells attach chondronectin help keep the cells positioned close to important collagen and proteoglycan materials within the extracellular matrix. This allows the cells to support the framework by maintaining surrounding cartilage components. Without attachment, chondrocytes become less effective at preserving the tissue around them. Chondronectin keeps the cartilage framework strong enough to handle daily joint pressure. It helps cartilage deal with the stress caused by regular movement and compression. Since joints face constant wear, cell bonds must stay stable to help prevent tissue damage. This protein plays a key role in keeping cartilage durable and properly supported. Studies indicate that weak adhesive interaction inside cartilage matrix can gradually reduce the integrity to cartilage.

fatigue. This is the most common complaint of people with autoimmune disease. A 2015 US survey found that 98% of people with autoimmune diseases experienced fatigue, 89% said it was a "major issue", 68% said "fatigue is anything but normal. It is profound and prevents [them] from doing the simplest everyday tasks." and 59% said it was "probably the most debilitating symptom of having an [autoimmune disease]." low-grade fever malaise (a general feeling of discomfort or unease) muscle aches joint pain skin rashes Autoimmune diseases can present a diverse array of symptoms. For instance, some people may experience dry mouth or dry eyes, tingling or numbness in various body parts, unexpected changes in weight, and diarrhea.

Not all ECM devices come from the bladder. Extracellular matrix coming from pig small intestine submucosa are being used to repair "atrial septal defects" (ASD), "patent foramen ovale" (PFO) and inguinal hernia. After one year, 95% of the collagen ECM in these patches has been replaced by the body with the normal soft tissue of the heart. Extracellular matrix proteins are commonly used in cell culture systems to maintain stem and precursor cells in an undifferentiated state during cell culture and function to induce differentiation of epithelial, endothelial and smooth muscle cells in vitro. Extracellular matrix proteins can also be used to support 3D cell culture in vitro for modelling tumor development. A class of biomaterials derived from processing human or animal tissues to retain portions of the extracellular matrix are called ECM Biomaterial.

Sources: en.wikipedia.org

Background from the literature

== How does Type IV collagen differ from Type I collagen? == The most common collagen is type I collagen which makes up 90% of all collagen. It is found in all dermal layers at high proportions while type IV collagen is only found at the basement membrane of the epidermal junction. Despite their differences in commonality, they are both strongly altered during aging or cancer progression.

Marfan syndrome - inherited as an autosomal dominant characteristic, due to mutations in the FBN1 gene that encodes fibrillin 1. Homocystinuria - condition of methionine metabolism brought on by a cystathionine β-synthase deficit that causes a build-up of homocysteine and its metabolites in the urine and blood. Ehlers–Danlos syndrome - diverse collection of disorders distinguished by the fragility of soft connective tissues and widespread symptoms affecting the skin, ligaments, joints, blood vessels, and internal organs. Osteogenesis imperfecta - hereditary condition marked by reduced bone mass, weakened bones, increased brittleness, and short stature. Alkaptonuria - inborn error of metabolism caused by mutations in the HGO gene and homogentisate 1,2-dioxygenase deficiency. Pseudoxanthoma elasticum - rare multisystem disease marked by gradual calcification and fragmentation of elastic fibres. Mucopolysaccharidosis - a class of hereditary illnesses distinguished by the excretion of mucopolysaccharide in the urine. Fibrodysplasia ossificans progressiva - rare and debilitating hereditary disorder characterized by progressive heterotopic ossification and congenital skeletal malformations. Familial osteochondritis dissecans - separation of the subchondral bone and cartilage from the surrounding tissue. Stickler syndrome - autosomal dominant disorder distinguished by skeletal, ocular, and orofacial abnormalities.

=== Excessive sugar intake === Too much sugar intake can negatively impact the body, including damage to collagen. Excess sugar consumption results in glycation that produces AGEs. This occurs naturally, and when too much sugar is consumed, the AGE molecules stick to the collagen molecules turning them stiff, thus damaging them. The process of glycation does not only damage the collagen existing in the body but also makes some alterations to its stability. When an individual consumes excessive amounts of sugar, the glycation process converts collagen into an unstable type 1, which becomes more vulnerable and can be easily broken down, potentially leading to premature aging.

Alexander Bont first made a name for himself when he killed the hero Defender. After that, he soon rose up the ranks and became the head of organized crime. The Fixer, the man who ordered the hit on Jack Murdock, paid up to Bont. When Daredevil found this out, he confronted Bont and had him arrested. Bont got out on bail. He later asked Matt Murdock for legal help, but was refused. When Bont was released from jail, he was now a bitter old man. He had found out that Daredevil was really Matt Murdock from The Globe and had acquired a possession of Mutant Growth Hormone (MGH). Bont learns how much the world has changed in his absence, including the death of his wife. Furious, Bont swears revenge on Daredevil. He meets with Melvin Potter and threatens to kill his young daughter, forcing Potter into working for him. Potter kidnaps Matt Murdock, then beats him. When White Tiger defeats Melvin Potter, Bont takes Mutant Growth Hormone to confront Daredevil. However, he overdoses on MGH, overloading his heart and killing him.

Sources: en.wikipedia.org

Frequently asked questions

What is cardarine?

Cardarine is a common name for GW501516, a synthetic PPARδ agonist developed for research. It has not been approved as a medication in any country. It is classified as an unapproved drug and a prohibited substance in sport.

Is cardarine a steroid?

No. Cardarine is not an anabolic steroid; it belongs to a different chemical class that targets PPARδ. Steroids act primarily through androgen receptors, while cardarine acts through a nuclear receptor involved in metabolism.

What did animal studies find?

Some rodent studies reported increased endurance and changes in fat metabolism after cardarine exposure. Long-term studies in animals also raised concerns about cancer in certain tissues. Human trial data are limited, so these findings cannot be directly translated to people.

Is cardarine a selective androgen receptor modulator?

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.

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