If you have been reading about fatty acid oxidation and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2026-08-01. Numbers and descriptions here follow the published literature rather than marketing material.
Laboratory studies indicate that GW501516 activates PPARδ, a nuclear receptor involved in fatty acid oxidation and energy metabolism. In rodent experiments, treated animals often showed increased endurance and reduced fat mass. These effects were observed under controlled conditions and do not establish safe or effective use in humans. The exact dose-response relationship in humans remains poorly characterized. Species differences in metabolism can affect how results translate across animals and people.
Safety concerns emerged from long-term animal studies. In rodents given the compound for extended periods, researchers found an increased incidence of certain cancers, including liver and bladder tumors. These findings contributed to the discontinuation of clinical development. Whether similar risks apply to short-term or low-level exposure in humans is not established, and controlled human safety data are limited. The relevance of high-dose rodent carcinogenicity findings to human use remains a subject of debate.
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.
| Property | Value | Notes |
|---|---|---|
| Primary target | PPARδ (NR1C2) | Nuclear receptor involved in lipid metabolism |
| Preclinical effect | Increased fatty acid oxidation | Observed in rodent studies |
| Key safety signal | Tumors in rodents after long-term exposure | Contributed to halted clinical development |
| Human trial status | No approved product; development stopped | Limited short-term metabolic data |
| Sport regulatory status | Prohibited at all times | WADA hormone and metabolic modulators class |
Laboratory studies have examined GW501516 in cell cultures and rodents for conditions such as dyslipidemia, insulin resistance, and obesity. Some trials in humans were initiated, but development was discontinued after preclinical findings raised concerns about cancer in certain models. Those findings do not prove that the compound causes cancer in people, but they contributed to regulatory caution. Later reviews often describe the evidence as preliminary and insufficient for assessing long-term safety.
In the fitness and bodybuilding literature, cardarine is frequently discussed as an endurance agent or fat-loss compound, although such claims are not supported by robust clinical evidence. Online descriptions often mix animal data, user anecdotes, and marketing language. Researchers who study PPARδ agonists distinguish between receptor activation in controlled experiments and unsupervised use of unverified products. The latter introduces unknown purity, dose, and interactions, making reported experiences difficult to interpret scientifically.
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.
Cardarine can be detected in biological samples and product materials using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The method separates compounds by chromatography and identifies them by mass-to-charge transitions, allowing low-level detection in urine or blood. Sample preparation often involves enzymatic hydrolysis, solid-phase extraction, or protein precipitation. Certified reference materials and isotope-labeled internal standards improve quantification. Detection windows depend on metabolism, matrix, and assay sensitivity, so no single universal window applies.
Regulatory treatment of cardarine differs by context and jurisdiction. In competitive sport, the World Anti-Doping Agency lists PPARδ agonists, including GW501516, as prohibited at all times. Outside sport, it lacks approval as a prescription medicine in major drug markets, and products sold for human consumption may be treated as unapproved drugs. Some countries also restrict importation or sale through general consumer protection and medicines laws. These classifications affect availability, testing, and legal risk without establishing therapeutic value.
Because cardarine is not an approved medicine, no pharmacopeial monograph defines its identity, purity, or storage requirements. Laboratories typically rely on in-house methods and reference standards when testing materials labeled as GW501516. Certificates of analysis may report purity and identity for a specific batch, but their scope varies and they do not guarantee safety or legal status. Independent verification can include high-performance liquid chromatography, mass spectrometry, nuclear magnetic resonance, and elemental analysis. The distinction between research chemical labeling and human use is significant because quality standards and oversight differ.
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.
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.
== Management == Early diagnosis and treatment can reduce the incidence of complications such as cataracts and neuropathy. Since dogs are insulin dependent, oral diabetes drugs, which require a functional endocrine pancreas with beta cells capable of producing insulin, are ineffective. Diabetic dogs require insulin therapy, which must be continued for life. The goal of treatment is to regulate blood glucose using insulin and some probable diet and daily routine changes. The process may take a few weeks or many months and is similar as in type 1 diabetic humans. The aim is to keep the blood glucose values in an acceptable range. The commonly recommended dosing method is by "starting low and going slow" as indicated for people with diabetes. During the initial process of regulation and periodically thereafter, the effectiveness of the insulin dose at controlling blood glucose is evaluated. This is done by a series of blood glucose tests called a curve. Blood samples are taken and tested at intervals of one to two hours over a 12- or 24-hour period. The results are generally transferred into graph form for easier interpretation. They are compared against the feeding and insulin injection times for judgment. The curve provides information regarding the action of the insulin in the animal.
=== EC 1.4.99 With unknown physiological acceptors === EC 1.4.99.1: Now EC 1.4.99.6, D-arginine dehydrogenase EC 1.4.99.2: taurine dehydrogenase EC 1.4.99.3: Now EC 1.4.9.1, methylamine dehydrogenase (amicyanin) EC 1.4.99.4: Now EC 1.4.9.2, aralkylamine dehydrogenase (azurin) EC 1.4.99.5: glycine dehydrogenase (cyanide-forming) EC 1.4.99.6: D-arginine dehydrogenase
Eccles, Jessica A.; Cadar, Dorina; Quadt, Lisa; Hakim, Alan J.; Gall, Nicholas; Bowyer, Vicky; Cheetham, Nathan; Steves, Claire J.; Critchley, Hugo D.; Davies, Kevin A. (2024). "Is joint hypermobility linked to self-reported non-recovery from COVID-19? Case–control evidence from the British COVID Symptom Study Biobank". BMJ Public Health. 2 (1) e000478. doi:10.1136/bmjph-2023-000478. PMC 11812800. PMID 40018183.
Sources: en.wikipedia.org
Metallothionein biosynthesis can also be induced by certain hormones, pharmaceuticals, alcohols, and other compounds. Metallothionein expression is upregulated during fetal development, particularly in liver tissue.
To the east of the garden and near the gallery of the Center Bourse is a large square basin made at the beginning of the 2nd century, about 15 m (49 ft) on each side, in well-paired stones, comprising on the whole five courses. The paved bottom was grouted with pitch to ensure watertightness. This basin of nearly 500 mᶟ was supplied with water by a pipe collecting water from a source and emerging in the north-eastern internal side of the basin. This pipeline, which was protected by Cassis stone slabs, was recognized over more than 100 m (330 ft) to the north. This basin was used to supply water to the boats. On the western internal facing, anchor points and a reserved cavity in the paved ground, attest to the existence of a wheel which must have been 3 m (9.8 ft) in diameter, used to clear the alluvium carried by the water. It is likely that another wheel was used to lift the water.
In 1807, Portugal refused Napoleon's demand to join the Continental System of embargo against the United Kingdom; an invasion led by General Junot followed, and Lisbon was captured in 1807. During the Napoleonic invasions, the Portuguese royal family transferred the court to Rio de Janeiro, in Brazil, making it the capital between 1808 and 1821. British intervention in the Peninsular War helped support Portuguese independence, and all French troops were expelled by 1812. In 1820, an uprising in Porto sought to establish a constitution for Portugal, forcing the return of King John VI and his court to mainland Portugal in 1821. Although the 1822 Constitution was adopted, the process was marked by compromise and efforts at consensus, which allowed absolutist forces to regain strength, leading to Miguelist counter-revolts against liberalism, prompting Prince Miguel's exile. After John VI's death in 1826, his eldest son, Pedro I of Brazil, briefly reigned as Pedro IV of Portugal, granted the 1826 Charter, and abdicated in favour of his minor daughter, Maria da Glória, on the condition that she marry Miguel, who was appointed regent. Although Miguel's return was under the condition of swearing allegiance to the Charter, he soon dismantled liberal institutions and was proclaimed king in 1828, leading to the Liberal Wars, after which Pedro forced Miguel's abdication in favour of Maria and his exile causing absolutist ideology to wane. Under the constitutional monarchy, the country faced economic crises, political instability, and several coups d'état.
=== Modern APG classification and phylogeny === The Angiosperm Phylogeny Group (APG) made rapid progress in establishing a modern monophyletic classification of the flowering plants by 2009. Despite establishing this relative degree of monophyly (genetic homogeneity) for the family Liliaceae, their morphology remains diverse and there exists within the Liliaceae clade or grouping, a number of subclades (subgroups). Particularly enigmatic were Clintonia, Medeola, Scoliopus, and Tricyrtis. Of the fifteen genera within the Liliaceae, the ten genera of the Lilioideae subfamily form one morphological group that is characterised by contractile bulbs and roots, and a Fritillaria-type embryo-sac (megagametophyte with four megaspores). Within the Lilioideae, Clintonia and the closely related Medeola form a subclade, and are now considered a separate tribe (Medeoleae). The other major grouping consists of the five genera constituting the Streptopoideae (including Scoliopus) and Calochortoideae (including Tricyrtis) subfamilies characterised by creeping rhizomes, styles which are divided at their apices, and by megagametophyte development of the Polygonum-type (a simple megaspore and triploid endosperm) embryo-sac.
Sources: en.wikipedia.org
With the exception of AlaRS, it has been discovered that 19 out of the 20 human aaRSs have added at least one new domain or motif. These new domains and motifs vary in function and are observed in various forms of life. A common novel function within human aaRSs is providing additional regulation of biological processes. There exists a theory that the increasing number of aaRSs that add domains is due to the continuous evolution of higher organisms with more complex and efficient building blocks and biological mechanisms. One key piece of evidence to this theory is that after a new domain is added to an aaRS, the domain becomes fully integrated. This new domain's functionality is conserved from that point on. As genetic efficiency evolved in higher organisms, 13 new domains with no obvious association with the catalytic activity of aaRSs genes have been added.
In January 1985, the sixth generation Familia/323 was fully renewed. It was available as a hatchback (with three or five doors) or four-door saloon only for the first year; wagon and cabriolet models were added in November 1985 and March 1986 respectively. The wagon was commonly sold as a light van in Japan, but for the first time it was also available as a passenger-oriented wagon model in the Japanese domestic market. In November 1986, cumulative production of Familias (excluding vans and pickups) reached five million units; at the time, Mazda was building about 40,000 Familia/323s per month. In January 1987 a personal coupé version with its own bodywork, the Étude, was added. In February 1987 the Familia range underwent a light facelift that included replacing the old E engines with the more modern B series. In some markets, such as Indonesia, the E engine continued to be installed after the facelift. This generation of the Familia/323 was also available in a version with a turbocharged DOHC engine, with either front- or four-wheel drive, producing 140 PS (103 kW). The 4WD version (sold in either a lightweight GT or fully optioned GT-X grade) introduced in October 1985, saw some success in rally's Group A category. A limited production Japanese-only homologation special, the 4WD GT-Ae, appeared May 1988 and offered an additional ten horsepower and viscous rear limited slip differential (similar to the later BG Familia). Full time four-wheel drive was also available in more pedestrian versions like the 1.5 hatchback.
Ears and sinuses: There is a risk of stretched or burst eardrums, usually crushed inwards during descent but sometimes stretched outwards on ascent. The diver can use a variety of methods to let air into or out of the middle ears via the Eustachian tubes. Sometimes swallowing will open the Eustachian tubes and equalise the ears. Lungs: There is a risk of pneumothorax, arterial gas embolism, and mediastinal and subcutaneous emphysema during ascent, which are commonly called burst lung or lung overpressure injury by divers. To equalise the lungs, all that is necessary is not to hold the breath during ascent. This risk does not occur when breath-hold diving from the surface, unless the diver breathes from an ambient pressure gas source underwater; breath-hold divers do suffer squeezed lungs on descent, crushing in the chest cavity, but, while uncomfortable, this rarely causes lung injury and returns to normal at the surface. Some people have pathology of the lung which prevent rapid flow of excess air through the passages, which can lead to lung barotrauma even if the breath is not held during rapid depressurisation. These people should not dive as the risk is unacceptably high. Most commercial or military diving medical examinations will look specifically for signs of this pathology. Diving mask squeeze enclosing the eyes and nose: The main risk is rupture of the capillaries of the eyes and facial skin because of the negative pressure difference between the gas space and blood pressure, or orbital emphysema from higher pressures.
Sources: en.wikipedia.org
Rodent studies reported increased endurance and fat oxidation after GW501516 exposure. Long-term studies also found higher rates of some tumors, which led to halted development.
Small short-term human trials examined metabolic markers such as lipids and glucose. The trials did not continue after rodent cancer findings, so long-term human safety is unknown.
Controlled human trials have not established a performance benefit. Anecdotal reports exist, but they are not reliable evidence.
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.