A practical reference on anti-doping: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-09-19 and is reviewed periodically as new material appears.
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.
GW501516 acts as an agonist at the peroxisome proliferator-activated receptor delta, a nuclear receptor that regulates gene expression. Activation shifts transcription toward genes involved in fatty acid uptake, oxidation, and energy expenditure. The compound does not bind the androgen receptor and therefore differs from anabolic steroids and SARMs. In rodent models, this metabolic shift has been linked to increased running endurance and reduced fat accumulation. The exact downstream pathways in humans remain incompletely characterized.
Early clinical research explored GW501516 for lipid disorders, obesity, and diabetes. Some short-term human studies reported changes in HDL cholesterol, LDL cholesterol, and triglycerides. The development program was discontinued after rodent studies showed dose-dependent tumor formation in multiple tissues, including liver, bladder, stomach, and skin. These findings raised concerns about long-term cancer risk in humans. Because human exposure data are limited, the clinical significance of the rodent tumors remains uncertain.
| Property | Value | Notes |
|---|---|---|
| Regulatory status | Prohibited in sport; not approved as medicine | Listed by WADA at all times. |
| Common synonyms | GW501516, GW-501516, endurobol | Cardarine is a colloquial name. |
| Typical analytical method | LC-MS/MS | Detects parent compound and metabolites. |
| Common test matrix | Urine | Blood and dried blood spots also possible. |
| Legal classification | Varies by country | Often treated as unapproved drug or research chemical. |
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.
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.
Stability of GW501516 depends on form, temperature, light exposure, and moisture. Solid reference material is typically stored frozen or refrigerated in a desiccator and protected from light. Solutions in organic solvents such as dimethyl sulfoxide are often kept frozen in aliquots to reduce freeze-thaw cycling. Aqueous solubility is low, so aqueous stock solutions can be difficult to prepare without cosolvents. Degradation may appear as changes in chromatographic purity or mass spectral signal. Stability studies are needed to establish shelf life for any specific preparation.
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.
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.
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.
Omacetaxine mepesuccinate (INN; trade name Synribo; formerly named as homoharringtonine or HHT) is a pharmaceutical drug substance that is indicated for treatment of chronic myeloid leukemia (CML). Omacetaxine approval in US is discontinued (August 2024)[1][2] and is no longer recommended for treatment of CML (as of NCCN CML guidance 3.2025) [3]. HHT is a natural plant alkaloid derived from Cephalotaxus fortunei. HHT and related compound esters of cephalotaxine were described first in 1970, and were the subject of intensive research efforts by Chinese investigators to clarify their role as anticancer and antileukemic agents from the 1970s until the present. It was approved by the US FDA in October 2012 for the treatment of adult patients with CML with resistance and/or intolerance to two or more tyrosine kinase inhibitors (TKIs).
Former fighters have told the media that the pills helped them overcome their fear. Doctors report that the drug has dangerous side effects, including psychosis and brain damage. According to former fighters, hundreds became addicted to the pills they were given by brigade leaders without knowing what they were taking. Fenethylline use was associated with the rise of jihadist group ISIS. One 19-year-old fighter named Kareem, who said he fought alongside ISIS for more than a year, told CNN in 2014: "They gave us drugs, hallucinogenic pills that would make you go to battle not caring if you live or die." In February 2023, Israel's Ministry of Defense claimed to have thwarted an attempt to smuggle thousands of fenethylline tablets from the West Bank into the Gaza Strip. Hamas claimed it had seized 50,000 fenethylline pills on the border, and claimed Israel was attempting to dope Gaza. Israel has publicly stated that fenethylline was used during the October 7 attacks, but this has been doubted by Caroline Rose, director of New Lines Institute's Strategic Blind Spots Portfolio. Israeli forces said they had found fenethylline-containing tablets, powder, and liquid on the bodies of the attackers. Rose said that she had never seen fenethylline made in liquid form. While precursor chemicals for fenethylline tend to be in powdered form, she said, fenethylline itself is not commonly a powder.
== External links == Media related to Earthworms at Wikimedia Commons Data related to Lumbricina at Wikispecies Chisholm, Hugh, ed. (1911). "Earthworm" . Encyclopædia Britannica (11th ed.). Cambridge University Press.
Sources: en.wikipedia.org
=== SB Pharmco Puerto Rico === In 2010, the US Department of Justice announced that GSK would pay a US$150 million criminal fine and forfeiture, and a civil settlement of US$600 million under the False Claims Act. The fines stemmed from production of improperly made and adulterated drugs from 2001 to 2005, at GSK's subsidiary, SB Pharmco Puerto Rico Inc., in Cidra, Puerto Rico, which at the time produced US$5.5 billion of products each year. The drugs involved were Kytril, an antiemetic; Bactroban, used to treat skin infections; Paxil, the anti-depressant; and Avandamet, a diabetes drug. GSK closed the factory in 2009. The case began in 2002, when GSK sent experts to fix problems cited by the FDA. The lead inspector recommended recalls of defective products, but they were not authorised; she was fired in 2003, and filed a whistleblower lawsuit. In 2005, federal marshals seized US$2 billion worth of products, the largest such seizure in history. In the 2010 settlement SB Pharmco pleaded guilty to criminal charges, and agreed to pay US$150 million in a criminal fine and forfeiture, at that time the largest such payment ever by a manufacturer of adulterated drugs, and US$600 million in civil penalties to settle the civil lawsuit.
=== Advantages === One of the advantages to automation is faster processing, but it is not necessarily faster than a human operator. Repeatability and reproducibility are improved as automated systems as less likely to have variances in reagent quantities and less likely to have variances in reaction conditions. Typically productivity is increased since human constraints, such as time constraints, are no longer a factor. Efficiency is generally improved as robots can work continuously and reduce the amount of reagents used to perform a reaction. Also there is a reduction in material waste. Automation can also establish safer working environments since hazardous compounds do not have to be handled. Additionally automation allows staff to focus on other tasks that are not repetitive.
Bromazepam is a "classical" benzodiazepine; other classical benzodiazepines include: diazepam, clonazepam, oxazepam, lorazepam, nitrazepam, flurazepam, and clorazepate. Its molecular structure is composed of a diazepine connected to a benzene ring and a pyridine ring, the benzene ring having a single nitrogen atom that replaces one of the carbon atoms in the ring structure. It is a 1,4-benzodiazepine, which means that the nitrogens on the seven-sided diazepine ring are in the 1 and 4 positions. Bromazepam binds to the GABAA receptor, causing a conformational change and increasing the inhibitory effects of GABA. It acts as a positive modulator, increasing the receptors' response when activated by GABA itself or an agonist (such as alcohol). As opposed to barbital, benzodiazepines are not GABA receptor activators and rely on increasing the neurotransmitter's natural activity. Bromazepam is an intermediate-acting benzodiazepine, is moderately lipophilic compared to other substances of its class and metabolised hepatically via oxidative pathways. It does not possess any antidepressant or antipsychotic qualities. After night time administration of bromazepam a highly significant reduction of gastric acid secretion occurs during sleep followed by a highly significant rebound in gastric acid production the following day. Bromazepam alters the electrical status of the brain causing an increase in beta activity and a decrease in alpha activity in EEG recordings.
Sources: en.wikipedia.org
Legal status varies by country. It is not approved as a medicine, and it is prohibited in sport. Some jurisdictions restrict import, sale, or possession.
Laboratories use liquid chromatography-tandem mass spectrometry to detect GW501516 and its metabolites. Urine is commonly tested, and testing can occur in and out of competition.
No, cardarine is not a SARM. It is a PPARδ agonist, which acts on a different receptor. The two classes are often confused in online discussions.
It targets PPARδ, a nuclear receptor involved in lipid and energy metabolism. It does not act primarily on androgen receptors. This distinction separates it from SARMs.