The short version of PPARδ fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-07-11. Anything still debated is marked as such rather than presented as settled.
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.
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.
Detection of GW501516 in biological samples generally relies on liquid chromatography coupled with tandem mass spectrometry. Urine is a common matrix in anti-doping analysis, while blood or plasma may be used in research settings. Sample preparation can involve enzymatic hydrolysis, protein precipitation, or solid-phase extraction before instrumental analysis. Because the compound undergoes metabolism, assays may target the parent molecule, one or more metabolites, or both. Detection windows are not fixed; they depend on factors such as dose, route, individual metabolism, and assay sensitivity. Reference standards are required for accurate identification and quantification.
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.
| 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. |
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.
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.
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.
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.
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.
Anti-doping laboratories identify GW501516 and its metabolites using liquid chromatography-tandem mass spectrometry. Urine is the usual matrix, and detection can occur after the parent compound has cleared from blood. The exact detection window depends on dose, formulation, individual metabolism, and assay sensitivity. Because the compound is prohibited at all times, athletes are subject to testing in and out of competition. Analytical methods continue to improve as new metabolites and designer analogs are characterized.
GW501516 acts as a ligand for PPAR delta, a nuclear receptor that regulates transcription of genes involved in fatty acid oxidation and energy use. Activation of this receptor in skeletal muscle shifts metabolism toward fat burning in animal models. The compound does not burn fat directly; it changes gene expression over hours to days. Researchers study it to understand metabolic flexibility and exercise adaptation. Effects observed in rodents are not automatically expected in humans.
Preclinical research reported that GW501516 increased running endurance in mice and improved lipid profiles in some animal species. Early human trials explored effects on high-density lipoprotein cholesterol, triglycerides, and glucose handling, but the program was discontinued. Published human data are sparse and do not establish efficacy for any condition. Studies also examined PPAR delta in cancer biology, with conflicting findings across models. The relationship between receptor activation, tissue context, and disease risk remains an active area of investigation.
In April 1927, Chiang Kai-shek purged the communists in the Shanghai Massacre, causing the collapse of the First United Front and the split within the Nationalists between the Nanjing and Wuhan governments. Despite his past alliances of convenience with progressives, Liu Wenhui joined with every other major Sichuan warlord to issue a joint telegram, declaring the orders of the Wuhan government "invalid." Later that year, he made a secret pact with fellow Baoding officers Tian Songyao and Deng Xihou, wherein Liu would support Deng and Tian in an offensive to take control of Chongqing, and the two would support Liu in his campaign to take over Xikang from Liu Chengxun. The planned offensive against Chongqing did not happen.
=== Trials of procedures === Similarly to drugs, medical or surgical procedures may be subjected to clinical trials, such as comparing different surgical approaches in treatment of fibroids for subfertility. However, when clinical trials are unethical or logistically impossible in the surgical setting, case-controlled studies will be replaced.
== Chemistry == Retatrutide is a peptide with the following amino acid sequence YA¹QGTFTSDYSIL²LDKK⁴AQA¹AFIEYLLEGGPSSGAPPPS³ where letters with superscripted numbers refer to the following chemical modifications:
Oxazepam is an intermediate-acting benzodiazepine of the 3-hydroxy family; it acts on benzodiazepine receptors, resulting in increased effect of GABA to the GABAA receptor which results in inhibitory effects on the central nervous system. The half-life of oxazepam is between 6 and 9 hours. It has been shown to suppress cortisol levels. Oxazepam is the most slowly absorbed and has the slowest onset of action of all the common benzodiazepines according to one British study. Oxazepam is an active metabolite formed during the breakdown of diazepam, nordazepam, and certain similar drugs. It may be safer than many other benzodiazepines in patients with impaired liver function because it does not require hepatic oxidation, but rather, it is simply metabolized by glucuronidation, so oxazepam is less likely to accumulate and cause adverse reactions in the elderly or people with liver disease. Oxazepam is similar to lorazepam in this respect. Preferential storage of oxazepam occurs in some organs, including the heart of the neonate. Absorption by any administered route and the risk of accumulation is significantly increased in the neonate, and withdrawal of oxazepam during pregnancy and breast feeding is recommended, as oxazepam is excreted in breast milk. Two milligrams of oxazepam equates to 1 mg of diazepam according to the benzodiazepine equivalency converter, therefore 20 mg of oxazepam according to BZD equivalency equates to 10 mg of diazepam and 15 mg oxazepam to 7.5 mg diazepam (rounded up to 8 mg of diazepam).
Sources: en.wikipedia.org
According to AASLD guidelines, a liver biopsy may be considered in people with MASLD who are at increased risk of having steatohepatitis with or without advanced fibrosis, but only when all other competing chronic liver diseases are excluded (such as alcoholic liver disease). The presence of metabolic syndrome, MASLD Fibrosis Score (FIB-4), or liver stiffness (as measured by Vibration-controlled transient elastography or MRE) can identify individuals who are at higher risk of steatohepatitis or advanced fibrosis.
=== Priapism === A relatively rare side effect associated with trazodone is priapism, likely due to its antagonism at α-adrenergic receptors. More than 200 cases have been reported, and the manufacturer estimated that the incidence of any abnormal erectile function is about one in 6,000 male patients treated with trazodone. The risk for this side effect appears to be greatest during the first month of treatment at low dosages (i.e. <150 mg/day). Early recognition of any abnormal erectile function is important, including prolonged or inappropriate erections, and should prompt discontinuation of trazodone treatment. Spontaneous orgasms have also been reported with trazodone in men. Clinical reports have described trazodone-associated psychosexual side effects in women as well, including increased libido, priapism of the clitoris, and spontaneous orgasms.
US forces reported killing approximately 144 individuals identified as narco-terrorists in airstrikes on suspected trafficking vessels during the Venezuelan authorities and human rights organizations disputed the US characterization, alleging many victims were civilians or fishermen. Casualties among Venezuelan military personnel and allies from related ground operations are covered in 2026 United States intervention in Venezuela.
===== Endopeptidases ===== Endopeptidases are enzymes that add water to an internal peptide bond in a peptide chain and break that bond. Three common endopeptidases that come from the pancreas are pepsin, trypsin, and chymotrypsin. Chymotrypsin performs a hydrolysis reaction that cleaves after aromatic residues. The main amino acids involved are serine, histidine, and aspartic acid. They all play a role in cleaving the peptide bond. These three amino acids are known as the catalytic triad which means that these three must all be present in order to properly function. Trypsin cleaves after long positively charged residues and has a negatively charged binding pocket at the active site. Both are produced as zymogens, meaning they are initially found in their inactive state and after cleavage though a hydrolysis reaction, they becomes activated. Non-covalent interactions such as hydrogen bonding between the peptide backbone and the catalytic triad help increase reaction rates, allowing these peptidases to cleave many peptides efficiently.
Cortisol is synthesized from cholesterol. Synthesis takes place in the zona fasciculata of an adrenal cortex. The name "cortisol" is derived from the word 'cortex'. Cortex means "the outer layer"—a reference to the adrenal cortex, the part of the adrenal gland where cortisol is produced. While the adrenal cortex in humans also produces aldosterone in the zona glomerulosa and some sex hormones in the zona reticularis, cortisol is its main secretion in humans and several other species. In cattle, corticosterone levels may approach or exceed cortisol levels. In humans, the medulla of the adrenal gland lies under its cortex, mainly secreting the catecholamines adrenaline (epinephrine) and noradrenaline (norepinephrine) under sympathetic stimulation. Synthesis of cortisol in the adrenal gland is stimulated by the anterior lobe of the pituitary gland with ACTH; ACTH production is, in turn, stimulated by CRH, which is released by the hypothalamus. ACTH increases the concentration of cholesterol in the inner mitochondrial membrane, via regulation of the steroidogenic acute regulatory protein. It also stimulates the main rate-limiting step in cortisol synthesis, in which cholesterol is converted to pregnenolone and catalyzed by cytochrome P450SCC (side-chain cleavage enzyme).
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.
Cardarine targets PPARδ, a nuclear receptor involved in lipid and energy metabolism. It does not bind the androgen receptor in the way SARMs do.