A practical reference on nuclear receptor: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-09-14. Anything still debated is marked as such rather than presented as settled.
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.
PPARδ is a nuclear receptor that regulates gene expression related to fatty acid oxidation, glucose homeostasis, and mitochondrial function. GW501516 binds to this receptor with high affinity and activates downstream signaling in skeletal muscle and other tissues. Animal studies reported increased endurance and altered fuel preference, but human data remain limited and inconsistent. The precise relationship between receptor activation and observed physiological changes is still an area of active investigation. Researchers have also examined whether the compound affects inflammation or cell proliferation. No approved therapeutic indication exists for cardarine.
In laboratory settings, cardarine is studied as a tool compound for probing PPARδ biology. Published experiments often use cell cultures, rodent models, or isolated tissues. Some investigations focus on metabolic effects, while others assess potential risks such as carcinogenicity observed in long-term animal studies. Because human trials are sparse, most knowledge comes from preclinical work and adverse event reports. Scientific literature frequently notes the gap between animal findings and human outcomes. The compound is not a dietary supplement and is not intended for human consumption.
Cardarine is a common name for GW501516, a synthetic compound developed in the 1990s through research collaborations involving GlaxoSmithKline. It belongs to a class of molecules known as peroxisome proliferator-activated receptor delta agonists. Early studies explored its effects on lipid metabolism and energy expenditure in animal models. The compound was never approved as a human medicine, and clinical development was discontinued. In the years since, it has appeared in fitness and bodybuilding communities as a performance-enhancing substance. Regulatory agencies classify it as an unapproved drug.
| 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 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.
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.
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.
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 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.
Addition of silica fume can yield exceptionally high strengths, and cements containing 5–20% silica fume are occasionally produced, with 10% being the maximum allowed addition under EN 197–1. However, silica fume is more usually added to Portland cement at the concrete mixer. Masonry cements are used for preparing bricklaying mortars and stuccos, and must not be used in concrete. They are usually complex proprietary formulations containing Portland clinker and a number of other ingredients that may include limestone, hydrated lime, air entrainers, retarders, waterproofers, and coloring agents. They are formulated to yield workable mortars that allow rapid and consistent masonry work. Subtle variations of masonry cement in North America are plastic cements and stucco cements. These are designed to produce a controlled bond with masonry blocks. Expansive cements contain, in addition to Portland clinker, expansive clinkers (usually sulfoaluminate clinkers), and are designed to offset the effects of drying shrinkage normally encountered in hydraulic cements. This cement can make concrete for floor slabs (up to 60 m square) without contraction joints. White blended cements may be made using white clinker (containing little or no iron) and white supplementary materials such as high-purity metakaolin. Colored cements serve decorative purposes. Some standards allow the addition of pigments to produce colored Portland cement. Other standards (e.g., ASTM) do not allow pigments in Portland cement, and colored cements are sold as blended hydraulic cements.
=== Positive symptoms === Positive symptoms are those for which function is gained: paresthesias, increased sensitivity, pain, muscle spasms, fasciculations. The symptoms represent hyperexcitability of a nerve where a signal is sent along a nerve due to a lower threshold for activation resulting in spontaneous signals. Demyelination can cause positive sensory symptoms such as pain due to increased ectopic firing. Demyelinated nerve tissue has been found to have a lower activation threshold for sending a signal, specifically for mechanosensitivity (e.g. light touch). While is some debate about the role of central nervous system sensitization in painful entrapment neuropathies, the success of peripheral nerve blocks suggests a peripheral nerve origin of this neuropathic pain.
Loss of consciousness can occur in myocardial infarctions due to inadequate blood flow to the brain and cardiogenic shock, and sudden death, frequently due to the development of ventricular fibrillation. When the brain was without oxygen for too long due to a myocardial infarction, coma and persistent vegetative state can occur. Cardiac arrest, and atypical symptoms such as palpitations, occur more frequently in females, the elderly, those with diabetes, in people who have just had surgery, and in critically ill patients.
The success of these concerts led to an appearance at the Classic Northwest concert at Safeco Field, opening again for the Eagles. The band took the last leg of their 2017 world tour to Europe, opening for Steely Dan. They toured again with Steely Dan the following year. This tour began in Charlotte, North Carolina and concluded in Bethel, New York. Former Allman Brothers percussionist Marc Quiñones joined the band in May 2018, and the band performed the Toulouse Street and The Captain and Me albums in their entirety along with a selection of hits, at the Beacon Theatre in New York City on November 15–16, 2018. These shows marked their first time at the theatre in 25 years. The concerts were recorded and released as a live album in 2019. During the summer of 2019, the band toured with Santana. Also in 2019, the band performed at the Ryman Auditorium in Nashville and performed the Toulouse Street and The Captain and Me albums in their entirety once again. Michael McDonald joined the band for an encore and they performed "Takin' It to the Streets". At the end of the concert, Simmons announced that McDonald would re-join the band for their 50th Anniversary tour. Since the early 2000s, they have headlined and performed at many benefit concerts including former manager Cohn's B.R. Cohn Winery in Glen Ellen where they had also shared the stage with McDonald in 2006 and 2012. Cohn sold his winery in 2015 to set his primary focus on managing the band and the B.R Cohn Charity Fall Music Festival was relocated to the Sonoma Valley Field of Dreams.
Sources: en.wikipedia.org
The attack on the World Trade Center's North Tower alone made 9/11 the deadliest act of terrorism in history. Taken together, the four crashes killed 2,996 people (including the hijackers) and injured thousands more. The death toll included 265 on the four planes (from which there were no survivors); 2,606 in the World Trade Center and the surrounding area; and 125 at the Pentagon. Most who died were civilians, as well as 343 firefighters, 72 law enforcement officers, 55 military personnel, and the 19 terrorists. More than 90 countries lost citizens in the attacks. In New York City, more than 90% of those who died in the towers had been at or above the points of impact. In the North Tower, between 1,344 and 1,402 people were at, above or one floor below the point of impact and all died. Hundreds were killed instantly when the plane struck. The estimated 800 people who survived the impact were trapped and died in the fires or from smoke inhalation, fell or jumped from the tower to escape the smoke and flames, or were killed in the building's collapse. The destruction of all three staircases in the North Tower when Flight 11 hit made it impossible for anyone from the impact zone upward to escape. 107 people not trapped by the impact died. When Flight 11 struck between floors 93 and 99, the 92nd floor was rendered inescapable: the crash severed all elevator shafts while falling debris blocked the stairwells, ensuring the deaths of all 69 workers on the floor. In the South Tower, around 600 people were on or above the 77th floor when Flight 175 struck; few survived.
== Single particle == In November 2017, an international team of scientists isolated a single proton in a Penning trap in order to measure its magnetic moment to the highest precision to date. It was found to be 2.79284734462(82) nuclear magnetons. The CODATA 2018 value matches this.
3-Hydroxyeticyclidine (3-HO-PCE) is a novel dissociative drug of the arylcyclohexylamine class, related to phencyclidine. It was first identified as a novel psychoactive substance in Sweden in 2017, and has subsequently been sold online as a research chemical. The toxicity and long-term safety profile of 3-HO-PCE is unknown as it has a very limited history of use, although one study indicates moderate potential toxicity.
6 April U.S. Space Command, based on information collected from its planetary defense sensors, confirms the detection of the first known interstellar object. The purported interstellar meteorite, technically known as CNEOS 2014-01-08, impacted Earth in 2014, and was determined, based on its hyperbolic trajectory and estimated initial high velocity, to be from beyond the Solar System. The 2014 meteorite was detected three years earlier than the more recent and widely known interstellar objects, ʻOumuamua in 2017 and 2I/Borisov in 2019. Further related studies were reported on 1 September 2023. The first known dinosaur fossil linked to the very day of the Chicxulub impact is reported by paleontologists at the Tanis site in North Dakota. One science journalist reflects on the global management of the COVID-19 pandemic in relation to science, investigating the question "Why the WHO took two years to say COVID is airborne" – a finding hundreds of scientists reaffirmed in an open letter in July 2020 – with one indication being that this may be a major concern for many expert scientists, as evidenced by several writings published by news outlets. A study decodes electrical communication between fungi into word-like components via spiking characteristics. Researchers demonstrate semi-automated testing for reproducibility (which is lacking especially in cancer research) via extraction of statements about experimental results in, as of 2022 non-semantic, gene expression cancer research papers and subsequent testing with breast cancer cell lines via robot scientist "Eve".
Human iron metabolism is the set of chemical reactions that maintain human homeostasis of iron at the systemic and cellular level. Iron is both necessary to the body and potentially toxic. Controlling iron levels in the body is a critically important part of many aspects of human health and disease. Hematologists have been especially interested in systemic iron metabolism, because iron is essential for red blood cells, where most of the human body's iron is contained. Understanding iron metabolism is also important for understanding diseases of iron overload, such as hereditary hemochromatosis, and iron deficiency, such as iron-deficiency anemia. A 2024 review examined iron metabolism and its interactions with calcium, magnesium, and selected trace elements (copper, zinc, lead, cadmium, mercury, and nickel), as well as their roles in certain diseases.
Sources: en.wikipedia.org
July–September 2024 Welsh Labour leadership election: Welsh Labour officials agree a timeline for the election, with a new leader to be in place on 14 September. Figures produced by the Institute for Fiscal Studies suggest the UK government would need to spend an extra £3bn to implement a 5.5% pay rise for teaching and NHS staff. 21 July It is confirmed that the bodies of Briton Sarah Packwood and her Canadian husband Brett Clibbery, who disappeared on 18 June while sailing their eco-friendly yacht across the Atlantic Ocean, were found on Sable Island near Nova Scotia on 12 July. Six people are killed in a crash between a car and a motorbike on the A61 road near Barnsley. 22 July – BT is fined £17.5m for a "catastrophic failure" of its emergency call handling service which led to thousands of 999 calls not being connected. 23 July Following a trial at Woolwich Crown Court, radical preacher Anjem Choudhary is convicted of directing the banned Islamist organisation Al-Muhajiroun. The Home Office confirms that the contract for the Bibby Stockholm, the vessel used to house asylum seekers, will not be renewed after January 2025. A report from the National Audit Office warns that the UK government may be forced to discourage people from travelling by train between Birmingham and Manchester after the Birmingham–Manchester leg of HS2 was scrapped. This is because HS2 trains will still continue on to Manchester, but will have fewer seats than the present rolling stock.
== Epidemiology == Marfan syndrome affects males and females equally, and the mutation shows no ethnic or geographical bias. Estimates indicate about 1 in 5,000 to 10,000 individuals have Marfan syndrome.
== Clinical significance == The inherited disease, dystrophic epidermolysis bullosa, is caused by recessive or dominant mutations in COL7A1. Recessive dystrophic epidermolysis bullosa, the most severe type of epidermolysis bullosa, has two subtypes, generalized intermediate and generalized severe, which have been linked to different mutations in the COL7A1 gene. Recessive dystrophic epidermolysis bullosa, generalized intermediate, is caused primarily by missense, in-frame, and splice-site mutations on one allele. The generalized severe subtype may be caused by premature termination codons in both alleles. These mutations cause little to no expression of collagen VII, which manifests primarily as generalized blistering in the skin and mucosal membranes. This blistering may also lead to several other complications, such as eye abrasions, esophageal stricture, deformity of the hands and feet, and squamous cell carcinoma, among others. Dominant dystrophic epidermolysis bullosa is most often caused by missense mutations, especially glycine substitutions in the collagenous domain. The symptoms of dominant dystrophic epidermolysis bullosa are less severe than those of the recessive types, with mild blistering and loss of nails. Epidermolysis bullosa acquisita involves an autoimmune reaction to this form of collagen. Beremagene geperpavec (Vyjuvek), is a gene therapy indicated for the treatment of wounds for people with dystrophic epidermolysis bullosa with mutation(s) in the collagen type VII alpha 1 chain (COL7A1) gene.
=== Eyes === Isotretinoin and other retinoids are well known to affect the eyes. Dry eyes are very common during treatment and is caused by isotretinoin's apoptotic effect on the meibomian glands. Some people develop contact lens intolerance as a result. In some people, these changes are long-lasting or irreversible and represent Meibomian Gland Dysfunction (MGD). Other common effects on the eyes include inflammation of the eyelid (blepharitis), red eye caused by conjunctivitis and irritation of the eye. More rare ocular side effects include blurred vision, decreased night vision (which may be permanent), colour blindness, development of corneal opacities, inflammation of the cornea (keratitis), swelling of the optic disk (papilloedema, associated with IIH), photophobia and other visual disturbances.
==== Developmental disorders ==== Hypospadias is a developmental disorder where the meatus is positioned wrongly at birth. Hypospadias can also occur iatrogenically by the downward pressure of an indwelling urethral catheter. It is usually corrected by surgery. A micropenis is a very small penis caused by developmental or congenital problems. Diphallia, or penile duplication (PD), is the rare condition of having two penises.
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 is a common name for GW501516, a synthetic PPARδ agonist developed for research. It has not been approved as a medication in any country. It is classified as an unapproved drug and a prohibited substance in sport.