A practical reference on PPARδ: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-09-10 and is reviewed periodically as new material appears.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | GW501516, GW-501516, GW 501516, endurobol | Names vary in research and anti-doping documents. |
| Chemical class | Synthetic PPARδ agonist | Small-molecule nuclear receptor ligand. |
| CAS Registry Number | 317318-70-0 | Identifier commonly associated with GW501516. |
| Appearance | White to off-white powder | Typical for purified research material. |
| Solubility | Low in water; soluble in DMSO and ethanol | Organic solvents are common for laboratory stock solutions. |
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.
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.
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.
== Chemistry == Mirtazapine is a tetracyclic piperazinoazepine; mianserin was developed by the same team of organic chemists and mirtazapine differs from it via the addition of a nitrogen atom in one of the rings. It is a racemic mixture of enantiomers. The (S)-(+)-enantiomer is known as esmirtazapine. Analogues of mirtazapine include mianserin, setiptiline, and aptazapine.
== Adverse effects == Motixafortide can cause injection site reactions, anaphylactic shock, and hypersensitivity reactions. Tumor cell mobilization in people with leukemia, leukocytosis, potential for tumor cell mobilization, and embryo-fetal toxicity can also be caused by motixafortide.
The first death row prisoner to be hanged in Singapore during the COVID-19 pandemic was 68-year-old Singaporean drug offender Abdul Kahar Othman on 30 March 2022, who had not appealed against his sentence and later executed as scheduled, therefore resuming executions in Singapore. By the time Abdul Kahar was executed, there were 62 prisoners on death row, awaiting execution (reduced to 61 with Nagaenthran's execution). Nagaenthran K. Dharmalingam was the second to be hanged on 27 April 2022 after Abdul Kahar. Datchinamurthy Kataiah was originally the third in line to be executed on 29 April 2022 after Nagaenthran before his execution was postponed due to an appeal. On 7 July 2022, Kalwant Singh Jogindar Singh and Norasharee Gous became the third and fourth convicts to be hanged in Singapore in 2022. In the same month, Nazeri Lajim was executed 15 days after Kalwant and Norasharee. Three more hangings - one on 26 July and two (Malaysian Rahmat Karimon and his accomplice Zainal Hamad) on 2 August - were conducted after Nazeri's execution. On 5 August 2022, 45-year-old Singaporean Abdul Rahim Shapiee and his 49-year-old accomplice Ong Seow Ping were the ninth and tenth to be executed. A 55-year-old Singaporean, whose name is unknown, was the eleventh to be executed for a drug charge on 7 October 2022. In total, eleven executions, all for drug trafficking, took place in the year 2022. In 2023, the first execution was carried out on 26 April 2023, when a 46-year-old Singaporean Tangaraju Suppiah, who was convicted in 2018 of marijuana trafficking, was hanged at dawn.
Sources: en.wikipedia.org
==== Geriatric use ==== For patients 65 years and older, it is unclear if there is a difference in response. However, older people often have decreased liver and kidney function which may lead to an increased level of naloxone in their body.
== Side effects and label warnings == The most common side effects are nausea, fatigue, vomiting, alopecia (hair loss), constipation, decreased appetite, anemia (hemoglobin in blood is below the reference range), decreased neutrophil count (white blood cells that help lead the body's immune system response to fight infection), diarrhea, leukopenia (other white blood cells that help the immune system), cough and decreased platelet count (component of blood whose function is to react to bleeding from blood vessel injury by clumping, thereby initiating a blood clot). The prescribing information for trastuzumab deruxtecan includes a boxed warning about the risk of interstitial lung disease (a group of lung conditions that causes scarring of lung tissues) and embryo-fetal toxicity. Interstitial lung disease and pneumonitis, including cases resulting in death, have been reported with trastuzumab deruxtecan.
Chronic dietary exposure to BMAA is now considered to be a cause of the amyotrophic lateral sclerosis/parkinsonism–dementia complex (ALS/PDC) that had an extremely high rate of incidence among the Chamorro people of Guam. The Chamorro call the condition lytico-bodig. In the 1950s, ALS/PDC prevalence ratios and death rates for Chamorro residents of Guam and Rota were 50–100 times that of developed countries, including the United States. No demonstrable heritable or viral factors were found for the disease, and a subsequent decline of ALS/PDC after 1963 on Guam led to the search for responsible environmental agents. The use of flour made from cycad seed (Cycas micronesica) in traditional food items decreased as that plant became rarer and the Chamorro population became more Americanized following World War II. Cycads harbor symbiotic cyanobacteria of the genus Nostoc in specialized roots which push up through the leaf litter into the light; these cyanobacteria produce BMAA. In addition to eating traditional food items from cycad flour directly, BMAA may be ingested by humans through biomagnification. Flying foxes, a Chamorro delicacy, forage on the fleshy seed covering of cycad seeds and concentrate the toxin in their bodies. Twenty-four specimens of flying foxes from museum collections were tested for BMAA, which was found in large concentrations in the flying foxes from Guam. As of 2021 studies continued examining BMAA biomagnification in marine and estuarine systems and its possible impact on human health outside of Guam.
Sources: en.wikipedia.org
Cardarine is an investigational synthetic compound that acts as a PPARδ agonist. It is also known as GW501516 and has been studied mainly in preclinical research. It is not an approved medicine.
No. Cardarine is not a steroid hormone; it targets the nuclear receptor PPARδ. Its classification in anti-doping rules differs from anabolic steroids, though it remains prohibited in sport.
Early rodent studies reported tumor formation at multiple sites, which raised safety concerns. Sponsors stopped clinical development, and no approved human product exists.
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.