anti-doping 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.
Updated 2025-09-15. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
Published literature on cardarine includes in vitro assays, rodent experiments, and a small number of human studies. Reports describe effects on exercise capacity and lipid metabolism in animals, while human evidence is sparse. Many online descriptions present the compound as a proven endurance aid, a claim not supported by regulatory approval or large clinical trials. Analytical studies focus on identifying the parent compound and its metabolites in biological samples. Important uncertainties include species differences, dose-response relationships, and the relevance of rodent tumor findings to humans.
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.
| Property | Value | Notes |
|---|---|---|
| IUPAC name | {4-[({4-methyl-2-[4-(trifluoromethyl)phenyl]-1,3-thiazol-5-yl}methyl)sulfanyl]phenoxy}acetic acid | Systematic name for GW501516 |
| CAS Registry Number | 317318-70-0 | Unique identifier for the parent compound |
| Molecular formula | C21H18F3NO3S2 | Includes carbon, hydrogen, fluorine, nitrogen, oxygen, and sulfur |
| Molecular weight | 453.5 g/mol | Approximate value for the neutral form |
| Appearance | White to off-white powder | Typical description for purified laboratory material |
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.
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.
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.
Following translation, small chemical groups can be added onto amino acids within the mature protein structure. Examples of processes which add chemical groups to the target protein include methylation, acetylation and phosphorylation. Methylation is the reversible addition of a methyl group onto an amino acid catalyzed by methyltransferase enzymes. Methylation occurs on at least 9 of the 20 common amino acids, however, it mainly occurs on the amino acids lysine and arginine. One example of a protein which is commonly methylated is a histone. Histones are proteins found in the nucleus of the cell. DNA is tightly wrapped round histones and held in place by other proteins and interactions between negative charges in the DNA and positive charges on the histone. A highly specific pattern of amino acid methylation on the histone proteins is used to determine which regions of DNA are tightly wound and unable to be transcribed and which regions are loosely wound and able to be transcribed. Histone-based regulation of DNA transcription is also modified by acetylation. Acetylation is the reversible covalent addition of an acetyl group onto a lysine amino acid by the enzyme acetyltransferase. The acetyl group is removed from a donor molecule known as acetyl coenzyme A and transferred onto the target protein. Histones undergo acetylation on their lysine residues by enzymes known as histone acetyltransferase. The effect of acetylation is to weaken the charge interactions between the histone and DNA, thereby making more genes in the DNA accessible for transcription.
One study of Tyrannosaurus specimens with tooth marks in the bones attributable to the same genus was presented as evidence of cannibalism. Tooth marks in the humerus, foot bones and metatarsals may indicate opportunistic scavenging, rather than wounds caused by combat. Other tyrannosaurids may also have practiced cannibalism.
== History == Amitriptyline was developed by the American pharmaceutical company Merck in the late 1950s. In 1958, Merck approached several clinical investigators proposing to conduct clinical trials of amitriptyline for schizophrenia. One of these researchers, Frank Ayd, instead, suggested using amitriptyline for depression. Ayd treated 130 patients and, in 1960, reported that amitriptyline had antidepressant properties similar to another, and the only known at the time, tricyclic antidepressant imipramine. Following this, the US Food and Drug Administration approved amitriptyline for depression in 1961. In Europe, due to a quirk of the patent law at the time allowing patents only on the chemical synthesis but not on the drug itself, Roche and Lundbeck were able to independently develop and market amitriptyline in the early 1960s. According to research by a historian of psychopharmacology David Healy, amitriptyline became a much bigger selling drug than its precursor imipramine because of two factors. First, amitriptyline has a much stronger anxiolytic effect. Second, Merck conducted a marketing campaign raising clinicians' awareness of depression as a clinical entity. Amitriptyline is no longer sold under the brand name Elavil.
=== Generic forms === Generic forms of oral selegiline are available in the United States. However, generic forms of the orally disintegrating tablet and the transdermal patch are not available in this country. The latter formulations of selegiline are very expensive, and this can be prohibitive to their use. There has been poor insurance coverage of the transdermal patch form for depression, with insurance companies often requiring patients to first fail to respond to one or two other antidepressants and to be responsible for larger copayments. It is expected that generics of the transdermal patch will become available at some point in the future.
=== June === 2 June – China successfully lands Chang'e 6 on the lunar far side. The robotic probe is set to begin sample collection before returning its 2 kg (4.4 lb) cargo on 4 June. 4 June – The China National Space Administration's Chang'e 6 spacecraft lifts off from the surface of the far side of the Moon carrying samples of lunar soil and rocks back to Earth. 5 June – Astronomers identify ASKAP J1935+2148, the slowest-spinning neutron star ever recorded, which completes a rotation just once every 54 minutes. 8 June – A paper challenges the public perception and media depictions of large language models like especially ChatGPT, arguing that "bullshitting" in the sense of the book On Bullshit and a fundamentally flawed design are a better approach or terminology for understanding the flaws of these AI architectures or the behavior of the systems based on these as opposed to occasional or frequent "hallucinations". In agreement with many other experts, they find these models are in an "important way indifferent to the truth of their outputs". This notion has also been applied to Perplexity AI that is typically used for generating outputs that are less inaccurate than ChatGPT's – or contain fewer "hallucinations" – and which was scaled up substantially during 2024. An investigation by WIRED reportedly showed the chatbot at times closely paraphrased WIRED stories, and at times summarized stories inaccurately and with minimal attribution.
Sources: en.wikipedia.org
== Production of biomass == Microbial cells or biomass is sometimes the intended product of fermentation. Examples include single cell protein, bakers yeast, lactobacillus, E. coli, and others. In the case of single-cell protein, algae is grown in large open ponds which allow photosynthesis to occur. If the biomass is to be used for inoculation of other fermentations, care must be taken to prevent mutations from occurring.
Photorespiration (also known as the oxidative photosynthetic carbon cycle or C2 cycle) refers to a process in plant metabolism where the enzyme RuBisCO oxygenates ribulose 1,5-bisphosphate (RuBP), wasting some of the energy produced by photosynthesis. The desired reaction is the addition of carbon dioxide to RuBP (carboxylation), a key step in the Calvin–Benson cycle, but approximately 25% of reactions by RuBisCO instead add oxygen to RuBP (oxygenation), creating a product that cannot be used within the Calvin–Benson cycle. This process lowers the efficiency of photosynthesis, potentially lowering photosynthetic output by 25% in C3 plants. Photorespiration involves a complex network of enzyme reactions that exchange metabolites between chloroplasts, leaf peroxisomes and mitochondria. The oxygenation reaction of RuBisCO is a wasteful process because 3-phosphoglycerate is created at a lower rate and higher metabolic cost compared with RuBP carboxylase activity. While photorespiratory carbon cycling results in the formation of G3P eventually, around 25% of carbon fixed by photorespiration is re-released as CO2 and nitrogen, as ammonia. Ammonia must then be detoxified at a substantial cost to the cell. Photorespiration also incurs a direct cost of one ATP and one NAD(P)H. While it is common to refer to the entire process as photorespiration, technically the term refers only to the metabolic network which acts to rescue the products of the oxygenation reaction (phosphoglycolate).
By August, eight of the nine republics, except Ukraine, had approved the draft of the new Treaty with some conditions. Ukraine did not agree on the terms of the Treaty. In the simultaneous Ukrainian republican referendum on 17 March, the majority of residents of Ukraine supported joining the Union on the basis of the 16 July 1990 Declaration of State Sovereignty of Ukraine. In addition, most of autonomous republics expressed the desire to raise their status and to be a party to the new Soviet treaty and declared sovereignty and self-promotion to republics during the parade of sovereignties in the months following the initial proposal from July 1990. Most of them participated in the Novo-Ogaryovo process to draft the treaty, and the status of former autonomous republics was a major point of contention among participants. On July 12, 1991, the Supreme Soviet passed the resolution "About the draft treaty on Union of Sovereign States" to state its stance on the matter that each of "the subjects of the federation, including both the sovereign states - the republics - and the republics incorporated within them on a treaty or constitutional basis" "possesses the right to sign the text of the Union Treaty". As a compromise, the final draft of the treaty allowed a state to join the Union as a part of another state, but only the nine republics were invited to sign it at Novo-Ogaryovo on July 23. Following the August coup, the New Union Treaty was further reformed into the Commonwealth of Independent States.
==== United States ==== Mephedrone has been implicated in the death of a 22-year-old man, who had also injected black tar heroin. Mephedrone was found in his blood at a concentration of 0.50 mg/L and in his urine at a concentration of 198 mg/L. The blood concentration of morphine, a metabolite of heroin, was 0.06 mg/L. For comparison, the average blood morphine concentration resulting from deadly overdoses involving only heroin is around 0.34 mg/L.
Sources: en.wikipedia.org
Many drivers have blood levels far exceeding the therapeutic dose range and often in combination with alcohol, illegal, or addictive prescription drugs, suggesting a high degree of potential for non-medical use of benzodiazepines, zolpidem, and zopiclone. Zopiclone, which at prescribed doses causes moderate impairment the next day, has been estimated to increase the risk of vehicle accidents by 50%, causing an increase of 503 excess accidents per 100,000 persons. Zaleplon or other nonimpairing sleep aids were recommended be used instead of zopiclone to reduce traffic accidents. Zopiclone, as with other hypnotic drugs, is sometimes used to carry out criminal acts such as sexual assaults. Zopiclone has crosstolerance with barbiturates and is able to suppress barbiturate withdrawal symptoms. It is frequently self-administered intravenously in studies on monkeys, suggesting a high risk of addictive potential. Zopiclone is in the top ten medications obtained using a false prescription in France.
Subsequent experiments showed that the 19 "cold" amino acids were not necessary and that the protein product had the biochemical characteristics of polyphenylalanine, demonstrating that a chain of repeated uracil bases produced a protein chain made solely of the repeating amino acid phenylalanine. While the experiment did not determine the number of bases per codon, it was consistent with the triplet codon UUU coding for phenylalanine. In analogous experiments with other synthetic RNAs, they found that poly-C directed synthesis of polyproline. Nirenberg recounts that the labs of Severo Ochoa and James Watson had earlier done similar experiments with poly-A, but failed to detect protein synthesis because polylysine (unlike most proteins) is soluble in trichloroacetic acid. Further, using synthetic RNAs that randomly incorporated two bases at different ratios, they produced proteins containing more than one type of amino acid, from which they could deduce the triplet nature of the genetic code and narrow down the codon possibilities for other amino acids. Nirenberg's group eventually decoded all the amino acid codons by 1966, however this required additional ingenious experimental methods (see Nirenberg and Leder experiment).
=== Abundance === The table gives crustal abundances of the elements commonly to rarely recognised as metalloids. Some other elements are included for comparison: oxygen and xenon (the most and least abundant elements with stable isotopes); iron and the coinage metals copper, silver, and gold; and rhenium, the least abundant stable metal (aluminium is normally the most abundant metal). Various abundance estimates have been published; these often disagree to some extent.
== AFL career == Steinberg was selected by Essendon with the thirty-first pick in the 2010 AFL draft in November 2010. Ariel was drafted from the Bendigo Pioneers in the TAC Cup having joined the Pioneers squad halfway through the 2010 season. He started playing for the Bendigo Bombers in their 2011 season. He kicked 3 goals against Frankston on 17 April 2011. He kicked 5 goals against the Box Hill Hawks on 19 June 2011. He kicked four goals against the Werribee Tigers on 7 August 2011. He kicked three goals against the Northern Bullants on 4 September 2011. He scored 25 goals in 2011. He was delisted in October 2015. Steinberg, along with 33 other Essendon players, was found guilty of using a banned performance-enhancing substance, thymosin beta-4, as part of Essendon's sports supplements program during the 2012 season. He and his teammates were initially found not guilty in March 2015 by the AFL Anti-Doping Tribunal, but a guilty verdict was returned in January 2016 after an appeal by the World Anti-Doping Agency. He was suspended for two years which, with backdating, ended in November 2016; as a result, he served approximately fourteen months of his suspension and missed the entire 2016 VFL season, during which time he had intended to play for VFL club Williamstown.
== Side effects == The most common adverse effects in studies were upper respiratory tract infection, headache, nausea, and diarrhea. The most common side effects in clinical trials were nasopharyngitis, nausea, headaches, herpes simplex (including oral herpes, ophthalmic herpes, herpes dermatitis and genital herpes), and increase in blood creatine phosphokinase. Abrocitinib can cause serious infections, malignancy, major cardiac events, thrombosis and other laboratory abnormalities including thrombocytopenia, lymphopenia, and lipid elevations. However, according to clinical data, Abrocitinib is well tolerated. The total adverse reactions were not statistically different between the placebo and the dose of 100 mg of abrocitinib. However, it was slightly higher for the dose of 200 mg of abrocitinib. Symptoms such as acne, headache, and nausea, appeared in the first two weeks of starting abrocitinib, and it was not necessary to interrupt the treatment. In general, the AE frequency of abrocitinib was the same or a little bit higher than in case of placebo or dupilumab.
Sources: en.wikipedia.org
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.
It is prohibited by the World Anti-Doping Agency as a hormone and metabolic modulator. Athletes who test positive for GW501516 can face sanctions, including suspensions and loss of results.
Cardarine is a common or trade-style name, while GW501516 is the research code for the same chemical entity. Some sources also use Endurobol or GSK-516. The names refer to the same compound, not distinct drugs.
Cardarine is a common name for the investigational compound GW501516. It acts as a PPARδ agonist and is not approved for human use. It is prohibited in sport.