The short version of Anti-doping fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-03-17. Anything still debated is marked as such rather than presented as settled.
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 has no approved therapeutic indication and is not marketed as a medicine. The World Anti-Doping Agency lists GW501516 as a prohibited substance at all times, covering both in-competition and out-of-competition periods. National laws vary: some countries treat it as an unapproved drug subject to import controls, while others have specific restrictions on sale for human consumption. It is often sold as a research chemical, a label that does not imply safety or legality. Enforcement actions have targeted online vendors and shipments.
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.
| Property | Value | Notes |
|---|---|---|
| Regulatory status | Prohibited in sport | Listed by WADA as a metabolic modulator. |
| Approved medical use | None in major jurisdictions | Not a registered drug. |
| Common test matrix | Urine | Most anti-doping samples use urine. |
| Typical detection method | LC-MS/MS | Detects parent compound and metabolites. |
| Reference standard storage | -20 °C, desiccated | Typical for analytical 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.
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.
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.
== Target == It seems likely that TsPep2 has inhibitory actions on potassium channels, based on its sequence similarities in the C-terminal beta sheet with the potassium channel inhibitory alpha family (α-KTX) and on its similarities in the patterns of disulfide bridges with other short scorpion venom toxins.
Impetigo herpetiformis Intrahepatic cholestasis of pregnancy (cholestasis of pregnancy, jaundice of pregnancy, obstetric cholestasis, prurigo gravidarum) Linea nigra Pemphigoid gestationis (gestational pemphigoid, herpes gestationis) Prurigo gestationis (Besnier prurigo, early-onset prurigo of pregnancy, linear IgM dermatosis of pregnancy, papular dermatitis of pregnancy, prurigo of pregnancy, Spangler's papular dermatitis of pregnancy) Pruritic folliculitis of pregnancy Pruritic urticarial papules and plaques of pregnancy (late-onset prurigo of pregnancy, polymorphic eruption of pregnancy, PUPPP syndrome, toxemic rash of pregnancy, toxic erythema of pregnancy) Striae gravidarum
The predominant cells of the liver are the hepatocytes, and GK is found exclusively in these cells. During digestion of a carbohydrate meal, when blood glucose is plentiful and insulin levels are high, hepatocytes remove glucose from the blood and store it as glycogen. After completion of digestion and absorption, the liver manufactures glucose from both non-glucose substrates (gluconeogenesis) and glycogen (glycogenolysis), and exports it into the blood, to maintain adequate blood glucose levels during fasting. Because GK activity rises rapidly as the glucose concentration rises, it serves as a central metabolic switch to shift hepatic carbohydrate metabolism between fed and fasting states. Phosphorylation of glucose to glucose-6-phosphate by GK facilitates storage of glucose as glycogen and disposal by glycolysis. The separate liver promoter allows glucokinase to be regulated differently in hepatocytes than in the neuroendocrine cells. Neuroendocrine cells of the pancreas, gut, and brain share some common aspects of glucokinase production, regulation, and function. These tissues are collectively referred to as "neuroendocrine" cells in this context. Beta cells and alpha cells of the pancreatic islets Beta cells release insulin in response to rising levels of glucose. Insulin enables many types of cells to import and use glucose, and signals the liver to synthesize glycogen. Alpha cells produce less glucagon in response to rising glucose levels, and more glucagon if blood glucose is low.
Sources: en.wikipedia.org
=== Blue Men of Lurgan === The "blue men of Lurgan" were a pair of Lurgan men suffering from what was described as "familial idiopathic methemoglobinemia" who were treated by James Deeny in 1942. Deeny, who would later become the Chief Medical Officer of the Republic of Ireland, prescribed a course of ascorbic acid and sodium bicarbonate. In case one, by the eighth day of treatments, there was a marked change in appearance, and by the twelfth day of treatment, the patient's complexion was normal. In case two, the patient's complexion reached normality over a month-long duration of treatment.
== Critical reception == The mod was well received by critics and fans alike. Matthew Byrd of Den of Geek called the mod "something that Half-Life fans should consider playing." For the week of August 18, 2018, it was one of the biggest stories on Mod DB. Liana Ruppert of Comicbook.com said that Echoes had "the compelling storyline, the intrigue - Echoes has it all!" Rick Lane of Bit-Tech called it "a superb, expansion-quality mod, and a must-play for any Half-Life fan." Half-Life: Echoes placed 3rd for the 2018 Mod of the Year Players' Choice and was an honorable mention for the 2019 Mod of the Year.
=== Distribution === Estradiol is rapidly distributed throughout the body, with a distribution phase of about 6 minutes following intravenous injection. Estradiol is taken up into cells via passive diffusion due to its lipophilicity. Due to binding to the ERs, estradiol is preferentially concentrated in tissues with the highest ER content. In animals, these tissues have included the uterus, vagina, mammary glands, pituitary gland, hypothalamus, other brain regions, adipose tissue, liver, and adrenal glands, among other tissues. In contrast to estradiol, due to its low affinities for the ERs, estrone is not accumulated in target tissues. Estradiol has been found to cross the blood–brain barrier in rhesus monkeys. The volume of distribution of estradiol has been found to be 0.85 to 1.17 L/kg. In another study however, its volume of distribution was only 0.082 ± 0.015 L/kg (4.8 L in women of average weight 58.4 kg). In terms of plasma protein binding, estradiol is bound loosely to albumin and tightly to SHBG, with approximately 97 to 98% of estradiol bound to plasma proteins. In the circulation, approximately 38% of estradiol is bound to SHBG and 60% is bound to albumin, with 2 to 3% free or unbound. However, with oral estradiol, there is an increase in hepatic SHBG production and hence SHBG levels (e.g., +50%), and this results in a relatively reduced fraction of free estradiol. As only free estradiol that is not bound to plasma proteins or SHBG is biologically active, this may reduce the potency of oral estradiol by some degree.
Sources: en.wikipedia.org
Aprepitant, sold under the brand name Emend among others, is a medication used to prevent chemotherapy-induced nausea and vomiting and to prevent postoperative nausea and vomiting. It may be used together with ondansetron and dexamethasone. It is taken by mouth or administered by intravenous injection. A prodrug, fosaprepitant, is also available for intravenous administration. Common side effects include tiredness, loss of appetite, diarrhea, abdominal pain, hiccups, itchiness, pneumonia, and blood pressure changes. Other severe side effects may include anaphylaxis. While use in pregnancy does not appear to be harmful, such use has not been well studied. Aprepitant belongs to the class of neurokinin-1 receptor antagonists. It works by blocking substance P from attaching to the NK1 receptors. Aprepitant was approved for medical use in the European Union and the United States in 2003. It is made by Merck & Co. It is on the World Health Organization's List of Essential Medicines.
At clinically studied doses in humans (up to 600 mg/day), which are much lower on a mg/kg basis than those used in the preceding animal studies, bicalutamide has only shown increases in testosterone levels and no testosterone suppression. There is some indication that the related NSAA nilutamide may also have SARM-like properties in certain tissues, as suggested by stimulation of erythropoiesis in men with prostate cancer. Additionally, hydroxyflutamide, the active metabolite of the related NSAA flutamide, has shown SARM-like activity in an androgen-responsive osteoblast cell line. Similarly, along with CPA, flutamide and hydroxyflutamide, though not bicalutamide, have been reported to act as SARMs or AR partial agonists in prostate cancer cells. Novel SARMs like enobosarm, with antiandrogenic effects in the prostate gland like bicalutamide but potent anabolic effects in muscle and bone, have also been developed. Bicalutamide has also been described as a functional "SARM" due to peripheral selectivity and inability to cross into the central nervous system and block ARs in this part of the body, resulting in antiandrogenic action in the periphery and lack of effects in the brain. However, while peripheral selectivity was initially observed in animal studies, bicalutamide did not end up showing peripheral selectivity in humans.
=== Addiction remission === The term fen-phen was created in 1994 when Pietr Hitzig and Richard B. Rothman reported that this combination could presumptively remit alcohol and cocaine craving. The authors suggested that other combined dopamine and serotonin agonists or precursors might share this therapeutic potential. Subsequent experiments in rats supported these preliminary reports. In 2006 it was confirmed that the combination of phentermine and the serotonin precursor 5-hydroxytryptophan (5-HTP), in place of fenfluramine, significantly decreased alcohol withdrawal seizures in rats. Intramural National Institutes of Health (NIH) double-blind protocols to demonstrate the efficacy of fen-phen in alcohol and cocaine addiction were designed, but never performed.
In biomedical sciences it is generally considered as a low resolution chromatography and thus it is often reserved for the final, "polishing" step of the purification. It is also useful for determining the tertiary structure and quaternary structure of purified proteins. SEC is used primarily for the analysis of large molecules such as proteins or polymers. SEC works also in a preparative way by trapping the smaller molecules in the pores of a particles. The larger molecules simply pass by the pores as they are too large to enter the pores. Larger molecules therefore flow through the column quicker than smaller molecules: that is, the smaller the molecule, the longer the retention time. This technique is widely used for the molecular weight determination of polysaccharides. SEC is the official technique of the European Pharmacopoeia for the molecular weight comparison of different commercially available low-molecular weight heparins.
Sources: en.wikipedia.org
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.
Anti-doping laboratories use LC-MS/MS to detect GW501516 and its metabolites, usually in urine. The method can identify the parent compound at low concentrations. Detection windows vary with dose and individual factors.
No, cardarine has no approved medical uses in major jurisdictions. Early research explored metabolic conditions, but those programs were discontinued. It is not a registered treatment for any disease.
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.