Investigational drug raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-06-24 and is reviewed periodically as new material appears.
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.
PPARδ is a nuclear receptor that influences transcription of genes involved in fatty acid oxidation, lipid transport, and energy homeostasis. GW501516 binds and activates this receptor with high selectivity relative to PPARα and PPARγ in laboratory assays. Activation alters expression of target genes in skeletal muscle, liver, and adipose tissue in animal models. The exact clinical consequences of these changes in humans remain incompletely characterized, and observed effects in animals do not establish therapeutic benefit or safety.
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.
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.
Cardarine is prohibited in competitive sport under the World Anti-Doping Agency code, where it is classified as a metabolic modulator. It is not approved as a prescription medicine in the United States, European Union, or other major markets. Regulatory action has focused on its presence in sports and in products marketed as research chemicals. Because it has no accepted medical indication, supply is often unregulated. This status creates legal and safety uncertainties for anyone who encounters the substance.
| Property | Value | Notes |
|---|---|---|
| Chemical class | PPARδ agonist | Not an anabolic steroid. |
| Common synonyms | GW501516, GW-1516 | Cardarine is an informal name. |
| Appearance | White to off-white powder | Typical for research-grade solid. |
| Solubility class | Poorly soluble in water; soluble in some organic solvents | Such as DMSO or ethanol in laboratory settings. |
| Typical storage temperature | Cool, dry, protected from light | Specific conditions vary by supplier and form. |
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 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.
Safety discussions about cardarine frequently cite rodent carcinogenicity findings reported in the 2000s. In those studies, treated animals developed tumors at multiple sites, leading sponsors to discontinue clinical development. The relevance of these findings to humans has not been resolved, but they are a major reason the compound is not approved. Current literature emphasizes uncertainty about long-term effects and the risks of unregulated use. Regulators and health agencies have not established a safe human exposure level.
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.
Toldt's fascia, is a discrete layer of connective tissue containing lymphatic channels. It is found between the two mesothelial layers that separate the mesocolon from the underlying retroperitoneum. It was first described by the Austrian anatomist Carl Toldt (1840–1920) as a fascial plane formed by the fusion of the visceral peritoneum with the parietal peritoneum. This was later called Toldt's fascia.
=== Absence === "Silent" myocardial infarctions can happen without any symptoms at all. These cases can be discovered later on electrocardiograms, using blood enzyme tests, or at autopsy after a person has died. Such silent myocardial infarctions represent between 22 and 64% of all infarctions, and are more common in the elderly, in those with diabetes mellitus and after heart transplantation. In people with diabetes, differences in pain threshold, autonomic neuropathy, and psychological factors have been cited as possible explanations for the lack of symptoms. In heart transplantation, the donor heart is not fully innervated by the nervous system of the recipient.
When the band emerged yet again in 1993, Hartman and Porter had retired from the road for good but Knudsen and McFee rejoined the Doobie Brothers on a full-time basis after Southern Pacific disbanded. Joined by Ockerman, Bumpus and Weeks, the group toured with Four Wheel Drive as the opening act. After Weeks left the tour to resume his session work, Cowan played bass for both bands. Bumpus also left to join the reunited Steely Dan, giving way to saxophonist, keyboardist and harmonica player Danny Hull. Former band member Chet McCracken temporarily filled in for an injured Hossack in July 1993. Their 1994 tour included co-headlining appearances with Foreigner. With renewed energy in the mid-1990s, the band began to experiment with different arrangements of several tunes. They even pulled from McDonald's songbook from time to time, eventually restoring "Takin' it to the Streets" to the setlist with Simmons and new bass guitarist Skylark (who joined in 1995) substituting for McDonald on lead vocals.
=== Metalloproteins and inorganic cofactors === Metalloproteins—in which the active site is a transition metal ion (or metal-sulfide cluster) often coordinated by sulfur atoms of cysteine residues—are essential components of enzymes involved in electron transfer processes. Examples include plastocyanin (Cu2+) and nitrous oxide reductase (Cu–S). The function of these enzymes is dependent on the fact that the transition metal ion can undergo redox reactions. Other examples include many zinc proteins, as well as iron–sulfur clusters. Most pervasive are the ferrodoxins, which serve as electron shuttles in cells. In bacteria, the important nitrogenase enzymes contain an Fe–Mo–S cluster and is a catalyst that performs the important function of nitrogen fixation, converting atmospheric nitrogen to ammonia that can be used by microorganisms and plants to make proteins, DNA, RNA, alkaloids, and the other organic nitrogen compounds necessary for life. Sulfur is also present in molybdenum cofactor.
Sources: en.wikipedia.org
==== Pharmaceuticals ==== The pharmaceutical industry constitutes the most important customer base for the fine chemical industry. The largest companies are Pfizer, USA; Roche, Switzerland, GlaxoSmithKline, UK; Sanofi Aventis, France, and Novartis, Switzerland. All are active in R&D, manufacturing and marketing. Pharmaceuticals containing more than 2000 different active ingredients are in commerce today; a sizable number of them are sourced from the fine chemical industry. The industry also has a track record of above-average growth. The fine chemical industry has a keen interest in the top-selling or "blockbuster drugs", those with worldwide annual sales in excess of $1 billion. Their number has increased steadily, from 27 in 1999 to 51 in 2001, 76 in 2003, and then levelled off.
== Clinical significance == Anti-endomysial antibodies (EMA) are present in celiac disease. They do not cause any direct symptoms to muscles, but detection of EMA is useful in the diagnosis of the disease.
In 2024, Andrea Cau published a study on the phylogenetics of compsognathids that called the assessment of these taxa into question. The paper recovered Sinosauropteryx, along with three other proposed compsognathids in a polytomy within basal Coelurosauria. This polytomy notably did not include Composognathus proper, which would make none of these species compsognathids. In their description of S. lingyuanensis, Qiu et al. (2025) also commented on the monophyly of Compsognathidae and revived the previously monotypic Sinosauropterygidae within Coelurosauria as a monophyletic family containing all compsognathid-like theropods from the Jehol Biota of China (Sinosauropteryx, Huadanosaurus, Huaxiagnathus and Sinocalliopteryx) in addition to Mirischia. Their phylogenetic analyses using two separate datasets are reproduced below:
The term reticulin was coined in 1892 by M. Siegfried. Today, the term reticulin or reticular fiber is restricted to referring to fibers composed of type III collagen. However, during the pre-molecular era, there was confusion in the use of the term reticulin, which was used to describe two structures:
=== Imaging studies === In some cases, imaging studies may be used to assess the extent of organ involvement and damage. For example, chest x-rays or CT scans can identify lung involvement in diseases like rheumatoid arthritis or systemic lupus erythematosus, while an MRI can reveal inflammation or damage in the brain and spinal cord in multiple sclerosis.
Sources: en.wikipedia.org
Cardarine is commonly known as GW501516 or GW-1516. These names refer to the same synthetic compound. It is not a brand-name approved medicine.
No, cardarine is not a steroid. It is classified as a PPARδ agonist. Its structure and receptor target differ from anabolic steroids.
No regulatory agency has approved cardarine as a medicine. It was investigated in early research but development was discontinued. It is not available as a prescription drug.
Legal status varies by country, but cardarine is not approved as a medicine in major jurisdictions. It is often sold as a research chemical, a category that may not be lawful for human use. Buyers should check local laws and product labels carefully.