Certificate of analysis raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-01-12 and is reviewed periodically as new material appears.
Cardarine is the common name for GW501516, a synthetic compound studied as a peroxisome proliferator-activated receptor delta agonist. Researchers developed it to explore treatments for lipid disorders and metabolic conditions. It is not an approved medicine in any country. Early clinical work examined changes in HDL cholesterol and triglycerides, but development was discontinued after animal studies raised concerns about cancer. The compound remains available as a research chemical and appears in discussions of performance enhancement.
At the molecular level, GW501516 binds and activates PPARδ, a nuclear receptor that regulates transcription. Activation shifts expression of genes involved in fatty acid oxidation, energy expenditure, and lipid transport in skeletal muscle and liver. Animal studies report increased endurance and altered lipid profiles after exposure. Human data are limited to small trials and do not establish long-term safety or efficacy. PPARδ also has roles in cell proliferation, so the relationship between activation and cancer risk remains an open question.
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.
| Property | Value | Notes |
|---|---|---|
| Common name | Cardarine | Also called GW501516 and endurobol. |
| Chemical formula | C21H18F3NO3S2 | Molecular weight about 453.5 g/mol. |
| Appearance | White to off-white solid | Form depends on synthesis and purity. |
| Solubility | Soluble in DMSO and ethanol | Low solubility in water. |
| Typical storage | -20 °C, desiccated, protected from light | Common for research chemicals. |
GW501516 acts as an agonist at the peroxisome proliferator-activated receptor delta, a nuclear receptor that regulates gene expression. Activation shifts transcription toward genes involved in fatty acid uptake, oxidation, and energy expenditure. The compound does not bind the androgen receptor and therefore differs from anabolic steroids and SARMs. In rodent models, this metabolic shift has been linked to increased running endurance and reduced fat accumulation. The exact downstream pathways in humans remain incompletely characterized.
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 not approved for human therapeutic use in any major jurisdiction. It appears on the World Anti-Doping Agency Prohibited List as a PPARδ agonist within the hormone and metabolic modulators category. Sports organizations test for it because it has been detected in athlete samples and seized products. Regulatory actions against marketed research chemical versions have occurred in several countries, though enforcement varies. Availability through unregulated channels complicates oversight.
Analytical laboratories typically identify cardarine and its metabolites using liquid chromatography-tandem mass spectrometry. Urine is a common matrix in anti-doping testing, while blood and tissue may be used in research settings. Detection windows depend on the assay, the sample matrix, and the compound's metabolism. Because cardarine is extensively metabolized, laboratories often target specific metabolites to improve sensitivity and confirmation. Reference standards are required for reliable quantification. Method validation includes checks for selectivity, linearity, and carryover.
A persistent misconception is that cardarine is a fat-burning drug or a safe alternative to anabolic steroids. No approved therapeutic product exists, and human safety data are limited. The tumor findings in rodents remain a central concern in scientific reviews. Products sold online may contain inaccurate labels, impurities, or different compounds entirely, which complicates any assessment of effects. Independent testing of such products has reported frequent mislabeling. For these reasons, discussions in the literature emphasize risks and unknowns rather than benefits.
Although sublingual administration of estradiol has a relatively short duration, the medication can be administered multiple times per day in divided doses to compensate for this. Studies that used high doses of sublingual estradiol in the treatment of severe postpartum depression have administered a dose of 1 mg 3 to 8 times per day. In one study, which administered a mean total dosage of sublingual estradiol of 4.8 mg/day, estradiol levels remained elevated at about 130 pg/mL on average in the morning before the first dose of the day. Oral micronized estradiol valerate tablets can be taken sublingually as well. The administration of 2 mg oral micronized estradiol valerate tablets (Progynova, Schering) sublingually 3 or 4 times per day resulted in circulating estradiol levels of about 290 pg/mL to 460 pg/mL in premenopausal women (time of measurements not given). Steady-state levels of estradiol were achieved within about 5 or 6 days. Levels of progesterone, luteinizing hormone, and follicle-stimulating hormone were all considerably suppressed, and ovulation, as well as the associated mid-cycle hormonal surges, were prevented. Sublingual estradiol valerate is used for cycle control in egg donation and surrogacy in cisgender women and is used in hormone therapy for transgender women. Cyclodextrin-containing formulations of sublingual estradiol with improved water solubility and absorption have been developed and studied.
However, the mobilization against the "peace process", as its defenders called it, did not prevent the government from initiating contacts with the ETA leadership. To put pressure on the government, ETA intensified street fighting (kale borroka) and finally on December 30, 2006, T-4 bombing placed a powerful bomb in the T-4 terminal of Barajas airport which caused the death of two people and enormous material damage. The government considered the "peace process" "suspended" and on June 4, ETA announced the end of the truce. Attacks were resumed and members of ETA and Batasuna were arrested. Likewise, the process of illegalization of the Communist Party of the Basque Homelands and Basque Nationalist Action began. In response ETA murdered in cold blood a former socialist councilman in the Gipuzkoan town of Mondragón on the eve of the March 2008 general election.
Spironolactone, also known as 7α-acetylthiospirolactone, is a steroidal 17α-spirolactone, or more simply a spirolactone. It can most appropriately be conceptualized as a derivative of progesterone, itself also a potent antimineralocorticoid, in which a hydroxyl group has been substituted at the C17α position (as in 17α-hydroxyprogesterone), the acetyl group at the C17β position has been cyclized with the C17α hydroxyl group to form a spiro 21-carboxylic acid γ-lactone ring, and an acetylthio group has been substituted in at the C7α position. These structural modifications of progesterone confer increased oral bioavailability and potency, potent antiandrogenic activity, and strongly reduced progestogenic activity. The C7α substitution is likely responsible for or involved in the antiandrogenic activity of spironolactone, as 7α-thioprogesterone (SC-8365), unlike progesterone, is an antiandrogen with similar affinity to the AR as that of spironolactone. In addition, the C7α substitution appears to be responsible for the loss of progestogenic activity and good oral bioavailability of spironolactone, as SC-5233, the analogue of spironolactone without a C7α substitution, has potent progestogenic activity but very poor oral bioavailability similarly to progesterone.
Robert Shonov, who worked in the US consulate in Vladivostok before being subcontracted to summarize Russian media reports for the embassy in Moscow was arrested, charged with cooperating "on a confidential basis with a foreign state, [or] international or foreign organisation", and detained at Lefortovo Prison. The State Department said the allegations were without merit. The FSB later said it had charged Shonov for “confidential collaboration” with a foreign state, allegedly collecting information on the Russian war effort in Ukraine, its military draft and protest activities in the run-up to the 2024 presidential elections. Hungary blocked the disbursement of an upcoming tranche of military support for Ukraine provided under the European Union's European Peace Facility (EPF), arguing that the fund was too focused on Ukraine and that the funds could be used elsewhere. Hungarian Foreign Minister Peter Szijjarto previously said that the country would block the disbursement as well as any new sanctions package on Russia until Ukraine removed OTP Bank, Hungary's largest commercial bank, in the list of sponsors of the war in Ukraine due to the position of the bank's management to continue operations in Russia and its client republics in the Donbas, which itself was based on a decision by the National Agency for the Prevention of Corruption of Ukraine. Hungary also demanded the removal of three people from a new sanctions list proposed by the European Commission as part of the 11th package of sanctions against Russia.
Sources: en.wikipedia.org
PFAS are used in Class B firefighting foams due to their hydrophobic and lipophobic properties, as well as the stability of the chemicals when exposed to high heat. Though studies have been frequently limited by underpowered study designs, research indicates firefighters have higher blood levels of PFOS and PFHxS than the general population. PFAS exposure is prevalent among firefighters not only due to its use in emergencies but also because it is used in personal protective equipment. In support of these findings, states like Washington and Colorado have moved to restrict and penalize the use of Class B firefighting foam for firefighter training and testing. The September 11 attacks and resulting fires caused the release of toxic chemicals used in materials such as stain-resistant coatings. First responders to this incident were exposed to PFOA, PFNA, and PFHxS through inhalation of dust and smoke released during and after the collapse of the World Trade Center. First responders who were working at or near ground zero were assessed for respiratory and other health effects from exposure to emissions at the World Trade Center. Early clinical testing showed a high prevalence of respiratory health effects. Early symptoms of exposure often presented with persistent coughing and wheezing. PFOA and PFHxS levels were present in both smoke and dust exposure, but first responders exposed to smoke had higher concentrations of PFOA and PFHxS than those exposed to dust.
=== 6 May === In Russia, the governor of Belgorod Oblast claimed that eight people were killed and 35 others were injured in a Ukrainian drone strike that hit three vehicles in the village of Berezovka. Russia claimed to have taken the villages of Soloviove in Donetsk Oblast and Kotliarivka in Kharkiv Oblast, 20 kilometers from Kupiansk. Ukraine claimed to have destroyed a Russian military fast attack craft in Crimea using a naval drone. Ukrainian forces claimed a series of successful counterattacks against Russian forces near Bakhmut, resulting in an advance of some 500 metres, and inflicting casualties on Russian soldiers and the destruction of four supply trucks, a BMP-2, and a BMD-4 using drones. Russia released footage of a Ka-29 opening fire on a Sea Baby drone armed with a R-73 infrared missile to defend it from helicopters. One missile appeared to have been fired before it was destroyed by gunfire. In response to perceived threats from France, Britain, and the United States, Russia announced it would practice the deployment of tactical nuclear weapons as part of a military exercise.
The matrix can be used to tune the instrument to ionize the sample in different ways. As mentioned above, acid-base like reactions are often utilized to ionize the sample, however, molecules with conjugated pi systems, such as naphthalene like compounds, can also serve as an electron acceptor and thus a matrix for MALDI/TOF. This is particularly useful in studying molecules that also possess conjugated pi systems. The most widely used application for these matrices is studying porphyrin-like compounds such as chlorophyll. These matrices have been shown to have better ionization patterns that do not result in odd fragmentation patterns or complete loss of side chains. It has also been suggested that conjugated porphyrin like molecules can serve as a matrix and cleave themselves eliminating the need for a separate matrix compound.
Sources: en.wikipedia.org
As booster vaccines for COVID-19 were rolled out in New Zealand early in 2022 with the wait time between the second and third doses shortened to three months, Turner responded to several suggestions about this. She refuted that the booster needed to be in the non-dominant arm, noting while it was good to keep fluid levels up during heat, drinking water, [won't] "make any difference to the vaccine response" and while stress on the immune system was understandable, there was little cause for concern. When the New Zealand government announced in May 2022 that there would be a second COVID-19 booster available to some members of the community, Turner expressed concern about the low rate of uptake for the first booster..."particularly the lower rate of boosters for older people and those with medical conditions...[adding]..."but still, there are quite a few people who feel like two doses aren't enough, and don't realise the importance of a booster". In November 2022, when parents of a four-month-old baby in New Zealand who needed heart surgery requiring a blood transfusion refused to accept blood from a donor who had received the COVID-19 vaccine, Turner said there was no scientific evidence suggesting there would be any risk to the baby. She noted [that] "blood donations are carefully screened for safety to ensure it was a match for the recipient", and people with concerns about this should talk to a professional.
== Electronic Associates, Inc. == In 1963, Finnigan and Uthe joined Electronic Associates, Inc. (EAI). The main research department of the company was based in Princeton, New Jersey, but Finnigan founded a new Scientific Instruments Division in Palo Alto, California. Finnigan's vision involved creation of a broad-based line of process-control instruments, beginning with the quadrupole mass spectrometer. Based on previous research at SRI, Finnigan was convinced that a market existed, but EAI and other companies such as IBM and Beckman Instruments were not interested in developing the quadrupole as a product at that time. Finnigan's group proposed to contract parts of the quadrupole production to SRI, but management at SRI were not interested in its commercial development either. Eventually Finnigan collaborated with staff from SRI, who supplied knowledge and expertise to help Finnigan's group bootstrap development of a prototype quadrupole analyzer at EAI. Because of the strong market demand the EAI division was able to sell more than 500 of these quadrupole residual gas analyzers between 1964 and 1966. Finnigan wanted to pursue development of computer-controlled instrumentation for a combined gas chromatograph (GC) and quadrupole mass spectrometer (MS). However, EAI's main focus was analog computers, and they were not interested in developing a computerized GC/MS. On December 31, 1966, after EAI unsuccessfully attempted to sell the division to Syntex Corporation, Finnigan submitted his resignation to EAI.
Arrestins block GPCR coupling to G proteins in two ways. First, arrestin binding to the cytoplasmic face of the receptor occludes the binding site for heterotrimeric G-protein, preventing its activation (desensitization). Second, arrestin links the receptor to elements of the internalization machinery, clathrin and clathrin adaptor AP2, which promotes receptor internalization via coated pits and subsequent transport to internal compartments, called endosomes. Subsequently, the receptor could be either directed to degradation compartments (lysosomes) or recycled back to the plasma membrane where it can again signal. The strength of arrestin-receptor interaction plays a role in this choice: tighter complexes tend to increase the probability of receptor degradation (Class B), whereas more transient complexes favor recycling (Class A), although this rule is far from absolute. More recently direct interactions between Gi/o family G proteins and Arrestin were discovered downstream of multiple receptors, regardless of canonical G protein coupling. These recent findings introduce a GPCR signaling mechanism distinct from canonical G protein activation and β-arrestin desensitization in which GPCRs cause the formation of Gαi:β-arrestin signaling complexes.
Sources: en.wikipedia.org
Cardarine is a common name for the investigational compound GW501516. It acts as a PPARδ agonist and is not approved for human use. It is prohibited in sport.
It activates PPARδ, a nuclear receptor that influences gene expression related to lipid and energy metabolism. Animal studies show changes in endurance and lipid levels. Human effects and risks are not well established.
No, cardarine is not a steroid. It belongs to a different chemical class, the PPARδ agonists. It is also not a selective androgen receptor modulator.
Anti-doping laboratories typically use LC-MS/MS to detect GW501516 and its metabolites in urine. The method is sensitive and can identify the compound at low concentrations. Detection depends on sample timing, metabolism, and the specific assay.