GW501516 is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-04-07. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Human trials of GW501516 were small and short in duration. They examined lipid levels, glucose handling, and other metabolic markers, but the programs were halted after the animal cancer findings. No approved therapeutic product exists, and published human data are insufficient for establishing long-term safety. Reports of use for athletic performance come mainly from non-clinical settings and cannot be verified through controlled trials. Independent testing of products sold as cardarine has found inconsistent purity and labeling.
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.
| 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 |
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.
Literature on cardarine often separates receptor pharmacology from toxicology. Mechanistic papers describe PPARδ activation and gene expression changes, while safety assessments focus on carcinogenicity and species differences. Questions remain about whether rodent tumors arise through PPARδ-dependent or off-target mechanisms. Another open area is how human metabolism and exposure compare with those in animal studies. Analytical methods such as liquid chromatography–mass spectrometry are used to confirm identity in biological and product samples.
Cardarine is a synthetic compound also known as GW501516, GW-501516, and sometimes endurobol. It was developed as a selective agonist of peroxisome proliferator-activated receptor delta, a nuclear receptor involved in fatty acid oxidation and energy metabolism. The compound was studied in preclinical models for metabolic and cardiovascular conditions, but it did not become a marketed human medicine. In regulatory and anti-doping contexts, it is treated as a prohibited substance rather than a licensed medicine.
The pharmacological interest in cardarine centers on PPARδ activation and its downstream effects on lipid handling and mitochondrial function. In animal studies, PPARδ agonists have been associated with changes in exercise endurance and fatty acid utilization, though results vary by model and protocol. Human data remain sparse, and the absence of large controlled trials limits conclusions about efficacy. Researchers often describe the compound as a tool for probing PPARδ biology rather than a proven therapeutic agent.
Safety discussions about cardarine frequently cite rodent carcinogenicity findings reported in the 2000s. In those studies, treated animals developed tumors at multiple sites, leading sponsors to discontinue clinical development. The relevance of these findings to humans has not been resolved, but they are a major reason the compound is not approved. Current literature emphasizes uncertainty about long-term effects and the risks of unregulated use. Regulators and health agencies have not established a safe human exposure level.
== Properties == An Affibody molecule consists of three alpha helices with 58 amino acids and has a molar mass of about 6 kDa. A monoclonal antibody, for comparison, is 150 kDa, and a single-domain antibody, the smallest type of antigen-binding antibody fragment, 12–15 kDa. Affibody molecules have been shown to withstand high temperatures (90 °C (194 °F)) or acidic and alkaline conditions (pH 2.5 or pH 11, respectively). Affibody molecules have ashort plasma half-life because of their small size.While this is advantageous for imaging,as the unbound tracer is rapidly cleared from the bloodstream, a longer plasma half-life is generally preferred for therapeutic applications. One approach to extend the plasma half-life of small molecules, such as affibody molecules,is to link them to an albumin-binding domain (ABD). A highly effective ABD is the 46-amino acid G148-GA3 domain, which is derived from streptococcal protein G, along with its engineered variant ABD035. This version has a strong femtomolar affinity for human serum albumin (HSA) [28]. The ABD can help prolong the serum half-life by forming a complex with serum albumin (SA) in the bloodstream, increasing the size of the complex and preventing it from being filtered by the kidneys. Binders with an affinity of down to sub-nanomolar have been obtained from native library selections, and binders with picomolar affinity have been obtained following affinity maturation. Affibody molecules conjugated to weak electrophiles bind their targets covalently.
Single-walled nanotubes are likely candidates for miniaturizing electronics. The most basic building block of these systems is an electric wire, and SWNTs with diameters of an order of a nanometre can be excellent conductors. One useful application of SWNTs is in the development of the first intermolecular field-effect transistors (FET). The first intermolecular logic gate using SWCNT FETs was made in 2001. A logic gate requires both a p-FET and an n-FET. Because SWNTs are p-FETs when exposed to oxygen and n-FETs otherwise, it is possible to expose half of an SWNT to oxygen and protect the other half from it. The resulting SWNT acts as a not logic gate with both p- and n-type FETs in the same molecule. Large quantities of pure CNTs can be made into a freestanding sheet or film by surface-engineered tape-casting (SETC) fabrication technique which is a scalable method to fabricate flexible and foldable sheets with superior properties. Another reported form factor is CNT fiber (a.k.a. filament) by wet spinning. The fiber is either directly spun from the synthesis pot or spun from pre-made dissolved CNTs. Individual fibers can be turned into a yarn. Apart from its strength and flexibility, the main advantage is making an electrically conducting yarn. The electronic properties of individual CNT fibers (i.e. bundle of individual CNT) are governed by the two-dimensional structure of CNTs. The fibers were measured to have a resistivity only one order of magnitude higher than metallic conductors at 300 K (27 °C; 80 °F).
=== 22 July === Ukrainian drones set fire to an oil refinery at Tuapse, Krasnodar Krai. Russian officials claimed the fire was put out, with no casualties and no “serious damage”. Russian air defence shot down some 75 drones over night over the Black and Azov Seas and over Belgorod, Voronezh, Smolensk and Rostov Oblasts. Mamuka Mamulashvili, the commander of the pro-Ukrainian militia Georgian National Legion, claimed that the State Security Service of Georgia placed about 300 members of the group on a wanted list. Boeing and Antonov signed a memorandum of understanding to collaborate on drone production and maintenance.
Sources: en.wikipedia.org
=== August === 1 August Tony Brien, 54, footballer (Leicester City, Chesterfield, Rotherham United, West Bromwich Albion, Mansfield Town, Chester City, Hull City). John Madigan, 76, hurler (Charleville, Avondhu) and rugby union player (UL Bohemians, Munster). 4 August – Colin O'Daly, 70, chef. 9 August – Art McRory, 82, Gaelic footballer (Dungannon, Tyrone senior team) and manager (Tyrone minor and senior teams). Born in Northern Ireland. 15 August – Liam McDaid, 78, Roman Catholic prelate. 23 August – Chryss Goulandris, 73, businesswoman, horse breeder and wife of Tony O'Reilly. Born in the United States.
==== Regeneration ==== Once saturated with water, the gel may be regenerated by heating it to about 120 °C (248 °F) for 1–2 hours. Some types of silica gel will "pop" when exposed to enough water. This is caused by breakage of the silica spheres when contacting the water. Regenerating silica gel is important for both economic and environmental reasons. It can be regenerated thermally or chemically. Chemical methods involve the use of desiccating agents or solvents to desorb water from silica gel, though these are generally less practical for routine regeneration. Thermal regeneration can be applied also to packed silica gel beds without opening them, and can be done by conventional heating in an oven at a temperature around 120 °C. Another option for thermal regeneration is by using microwaves to apply heat more evenly and reduce regeneration time compared to conventional ovens, but this process should be tightly controlled to avoid overheating. Yet another option to apply heat is using a solar heater with a compound parabolic concentrator. There are also studies on using ultrasonic waves to remove water molecules from silica gel at 45–90 °C which are lower temperatures than that of conventional heating.
==== Computer tomography ==== In 1972, the first commercial CT scanner for clinical use went into operation at Atkinsons Morley Hospital in London. Its inventor was the English engineer Godfrey Newbold Hounsfield (1919-2004), who shared the 1979 Nobel Prize in Medicine with Allan McLeod Cormack (1924-1998) for his pioneering work in the field of computed tomography. The first steps toward dose reduction were taken in 1989 in the era of single-slice spiral CT. The introduction of multi-slice spiral computed tomography in 1998 and its continuous development made it possible to reduce the dose by means of dose modulation. The tube current is adjusted, for example by reducing the power for images of the lungs compared to the abdomen. The tube current is modulated during rotation. Because the human body has an approximately oval cross-section, radiation intensity is reduced when radiation is delivered from the front or back, and is increased when radiation is delivered from the side. This dose control also depends on the body mass index. For example, the use of dose modulation in the head and neck region reduces total exposure and organ doses to the thyroid and eye lens by up to 50% without significantly compromising diagnostic image quality. The Computed Tomography Dose Index (CTDI) is used to measure radiation exposure during a CT scan. The CTDI was first defined by the Food and Drug Administration (FDA) in 1981. The unit of measurement for the CTDI is the mGy (milli-Gray).
== Life == Roderich Süssmuth studied chemistry and biochemistry at the Eberhard Karls University of Tübingen from 1990 to 1996. In 1999, he received his doctorate under Günther Jung in Tübingen with a dissertation entitled Isolation, structural elucidation, and synthesis of microbial metabolites from Amycolatopsis mediterranei, Staphylococcus epidermidis, and Streptomyces lividans. During a postdoctoral stay at the Scripps Research Institute in La Jolla, California, United States, from 2000 to 2001, he worked with Richard A. Lerner and Carlos F. Barbas on catalytic antibodies and organocatalysis. As an Emmy Noether Research Fellow (DFG) from 2001 to 2004, he completed his habilitation in chemistry and biochemistry at the University of Tübingen. In 2004, he was appointed Associate Professor of Biological Chemistry at TU Berlin. In 2008, he was appointed to the Rudolf Wiechert Professorship of Biological Chemistry at TU Berlin. In 2020, he was named a Fellow of the Royal Society of Chemistry (FRSC) and an honorary member of the Israel Chemical Society. In 2022, he was admitted to the Confraternity of Santa Maria dell'Anima in Rome.
Sources: en.wikipedia.org
Voltaire does not speculate on where the Circassians derived their technique from, though he reports that the Chinese have practiced it "these hundred years". Variolation was also practiced throughout the latter half of the 17th century by physicians in Turkey, Persia, and Africa. In 1714 and 1716, two reports of the Ottoman Empire Turkish method of inoculation were made to the Royal Society in England, by Emmanuel Timoni, a doctor affiliated with the British Embassy in Constantinople, and Giacomo Pylarini. Source material tells us on Lady Mary Wortley Montagu; "When Lady Mary was in the Ottoman Empire, she discovered the local practice of inoculation against smallpox called variolation." In 1718 she had her son, aged five, variolated. He recovered quickly. She returned to London and had her daughter variolated in 1721 by Charles Maitland, during an epidemic of smallpox. This encouraged the British royal family to take an interest and a trial of variolation was carried out on prisoners in Newgate Prison. This was successful and in 1722 Caroline of Ansbach, the Princess of Wales, allowed Maitland to vaccinate her children. The success of these variolations assured the British people that the procedure was safe.
=== Gray hair === Low levels of catalase may play a role in the graying process of human hair. Hydrogen peroxide is naturally produced by the body and broken down by catalase. Hydrogen peroxide can accumulate in hair follicles and if catalase levels decline, this buildup can cause oxidative stress and graying. These low levels of catalase are associated with old age. Hydrogen peroxide interferes with the production of melanin, the pigment that gives hair its color.
In 1958, the UN established a Good Offices Committee which continued to invite South Africa to bring South West Africa under trusteeship. The Good Offices Committee proposed a partition of the mandate, allowing South Africa to annex the southern portion while either granting independence to the north, including the densely populated Ovamboland region, or administering it as an international trust territory. The proposal met with overwhelming opposition in the General Assembly; fifty-six nations voted against it. Any further partition of South West Africa was rejected out of hand.
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.
Cardarine targets PPARδ, a nuclear receptor involved in lipid and energy metabolism. It does not bind the androgen receptor in the way SARMs do.