Metabolic modulator comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2025-11-24. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
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.
| 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. |
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.
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 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.
== Side effects == Most frequent side effects are nausea, orthostatic hypotension, headaches, and vomiting through stimulation of the brainstem vomiting centre. Vasospasms with serious consequences such as myocardial infarction and stroke that have been reported in connection with the puerperium, appear to be extremely rare events. Peripheral vasospasm (of the fingers or toes) can cause Raynaud's phenomenon. Bromocriptine use has been anecdotally associated with causing or worsening psychotic symptoms (its mechanism is in opposition of most antipsychotics, whose mechanisms generally block dopamine receptors). It should be understood, however, that the greater affinity bromocriptine and many similar antiparkinson's drugs have for the D2S receptor form (considered to be mostly present at inhibitory D2 autoreceptor locatations) relative to the D2L form, sufficiently low partial agonist activity (i.e. where a molecule binding to a receptor induces limited effects while preventing a stronger ligand like dopamine from binding), and, possibly, the functional selectivity of a particular drug may generate antidopaminergic effects that are more similar than oppositional in nature to antipsychotics. Pulmonary fibrosis has been reported when bromocriptine was used in high doses for the treatment of Parkinson's disease.
Hydra vulgaris, (previously Hydra magnipapillata), a model hydrozoan (2010) Nematostella vectensis, a model sea anemone (starlet sea anemone) (2007) Aiptasia pallida, a sea anemone (2015) Renilla muelleri, an octocoral (2017, 2019) Stylophora pistillata, a coral (2017) Aurelia aurita, moon jellyfish (2019) Clytia hemisphaerica, Hydrozoan jellyfish (2019) Myxobolus honghuensis (2022) Nemopilema nomurai, Nomura jellyfish (2019) Rhopilema esculentum, Flame jellyfish (2020) Cassiopea xamachana (Scyphozoa) (2019) Alatina alata (Cubozoa) (2019) Calvadosia cruxmelitensis (Staurozoa) (2019) Dendronephthya gigantea, an octocoral (2019) Acropora acuminata (2020) Acropora awi (2020) Acropora cytherea, Table coral (2020) Acropora digitifera, a coral (2011) Acropora echinata (2020) Acropora florida, branching staghorn coral(2020) Acropora gemmifera (2021) Acropora hyacinthus, Brush coral (2020) Acropora intermedia, Noble Staghorn Coral (2020) Acropora microphthalma (2020) Acropora muricata, Staghorn coral (2020) Acropora nasta, branching staghorn coral (2020) Acropora pulchra (2025) Acropora selago, Green Selago Acropora (2020) Acropora tenuis, Purple Tipped Acropora (2020) Acropora yongei ,Yonge's staghorn coral (2020) Corallium rubrum, Precious coral (2024) Astreopora myriophthalma, Porous star coral (2020) Lophelia pertusa, Deepwater White Coral (2023) Montipora cactus (2020) Montipora capitata, Rice coral (2022) Montipora efflorescens, Velvet coral (2020) Orbicella faveolata, mountainous star coral (2016) Paragorgia papillata, Bubble-gum coral (2025) Pocillopora acuta, Hosoeda Hanayasai coral (2022) Pocillopora damicornis, cauliflower coral (2018) Pocillopora meandrina, Cauliflower coral (2022) Porites astreoides, Mustard hill coral (2022) Porites compressa, Finger coral (2022)
In pharmacology and pharmaceutics, a prototype drug is an individual drug that represents a drug class – group of medications having similar chemical structures, mechanism of action and mode of action. Prototypes are the most important, and typically the first developed drugs within the class, and are used as a reference to which all other drugs are compared.
RCH(NHP)CO2H + R'CH(NH2)CO2CH3 → RCH(NHP)C(O)NH(CHR')CO2CH3 + H2O Subsequent to this coupling reaction, the amine protecting group P and the ester are converted to the free amine and carboxylic acid, respectively. For many amino acids, the ancillary functional groups are protected. The condensation of the amine and the carboxylic acid to form the peptide bond generally employs coupling agents to activate the carboxylic acid. The Bergmann azlactone peptide synthesis is a classic organic synthesis for the preparation of dipeptides.
Oxycodone, a semi-synthetic opioid, is a highly selective full agonist of the μ-opioid receptor (MOR). This is the main biological target of the endogenous opioid neuropeptide β-endorphin. Oxycodone has low affinity for the δ-opioid receptor (DOR) and the κ-opioid receptor (KOR), where it is an agonist similarly. After oxycodone binds to the MOR, a G protein-complex is released, which inhibits the release of neurotransmitters by the cell by decreasing the amount of cAMP produced, closing calcium channels, and opening potassium channels. Opioids like oxycodone are thought to produce their analgesic effects via activation of the MOR in the midbrain periaqueductal gray (PAG) and rostral ventromedial medulla (RVM). Conversely, they are thought to produce reward and addiction via activation of the MOR in the mesolimbic reward pathway, including in the ventral tegmental area, nucleus accumbens, and ventral pallidum. Tolerance to the analgesic and rewarding effects of opioids is complex and occurs due to receptor-level tolerance (e.g., MOR downregulation), cellular-level tolerance (e.g., cAMP upregulation), and system-level tolerance (e.g., neural adaptation due to induction of ΔFosB expression). Taken orally, 20 mg of immediate-release oxycodone is considered to be equivalent in analgesic effect to 30 mg of morphine, while extended release oxycodone is considered to be twice as potent as oral morphine. Similarly to most other opioids, oxycodone increases prolactin secretion, but its influence on testosterone levels is unknown.
Sources: en.wikipedia.org
19 December – With the UK government signalling its willingness to delay local elections due in May 2026 for a year, the Electoral Commission raises concerns about further delays to elections, describing the process as one that is "damaging public confidence". 21 December – The Electoral Commission finds no "credible evidence of potential offences of electoral law" over Nigel Farage's election expenses. Scottish Labour MSP Pam Duncan-Glancy confirms she will not seek re-election to the Scottish Parliament at the 2026 election because she does not want her friendship with a convicted sex offender to "become a distraction". 22 December – Liberal Democrat leader Sir Ed Davey writes to the Equalities and Human Rights Commission to ask it to investigate government plans to delay local elections, which could affect as many as 10 million voters. The leader of Plymouth City Council confirms that local elections there will go ahead in May, but local elections in Exeter are still uncertain. 23 December – The UK government announces it is watering down its plans for inheritance tax on farmers, and will raise the threshold from £1m to £2.5m. Local Government Secretary Steve Reed writes to councils in England warning them not to adopt a four-day working week. Scotland's Justice Secretary, Angela Constance, is to face an investigation over comments she made about a grooming gang expert to determine whether she broke the ministerial code.
Contemporary global warming is driven by human activities, despite claims that it is not occurring, lacks strong scientific consensus, or that warming is mostly caused by non-human factors. No scientific body of national or international standing disagrees with the decades-old, near-complete scientific consensus on climate change. Global warming is primarily a result of the increase in atmospheric greenhouse gas concentrations (like CO2 and methane) via the burning of fossil fuels as well as other human activities such as deforestation, with secondary climate change feedback mechanisms (such as the melting of the polar ice increasing the Earth's absorption of sunlight) assisting to perpetuate the change. Global warming is not caused by the hole in the ozone layer. Ozone depletion is a separate problem caused by chlorofluorocarbons (CFCs) which have been released into the atmosphere. CFCs are strong greenhouse gases; however, the hole in the ozone layer is shrinking and in 2019 was the smallest it had been since 1982, while global warming continues. Cooling towers in power stations and other facilities do not emit smoke, harmful fumes, or radiation; they emit water vapor and do not contribute to climate change. Nuclear power is one of the safest sources of energy, resulting in orders of magnitude fewer deaths than conventional power sources per unit of energy produced. Extremely few people are killed or injured due to nuclear power on a yearly basis. (See also: Radiophobia) Earthquake strength (or magnitude) is not commonly measured using the Richter scale.
=== Importance for storage and long-term survival of memory B and memory T cells === Bone marrow is a nest for migratory memory T cells and a sanctuary for plasma cells. This has implications for adaptive immunity and vaccinology. Memory B and T cells persist in the parenchyma in dedicated survival niches organized by stromal cells. This memory can be maintained over long time periods in the form of quiescent cells or by repeated antigenic restimulation. Bone marrow protects and optimizes immunological memory during dietary restriction. In cancer patients, cancer-reactive memory T cells can arise in bone marrow spontaneously or after specific vaccination. Bone marrow is a center of a variety of immune activities: i) hematopoiesis, ii) osteogenesis, iii) immune responses, iv) distinction between self and non-self antigens, v) central immune regulatory function, vi) storage of memory cells, vii) immune surveillance of the central nervous system, viii) adaptation to energy crisis, ix) provision of mesenchymal stem cells for tissue repair.
(3) Post- synthetic modification of MOFs increased their functionality by reacting organic units and metal-organic complexes with linkers. (4) Multifunctional MOFs incorporated multiple functionalities in a single framework. Since ligands in MOFs typically bind reversibly, the slow growth of crystals often allows defects to be redissolved, resulting in a material with millimeter-scale crystals and a near-equilibrium defect density. Solvothermal synthesis is useful for growing crystals suitable to structure determination, because crystals grow over the course of hours to days. However, the use of MOFs as storage materials for consumer products demands an immense scale-up of their synthesis. Scale-up of MOFs has not been widely studied, though several groups have demonstrated that microwaves can be used to nucleate MOF crystals rapidly from solution. This technique, termed "microwave-assisted solvothermal synthesis", is widely used in the zeolite literature, and produces micron-scale crystals in a matter of seconds to minutes, in yields similar to the slow growth methods. Some MOFs, such as the mesoporous MIL-100(Fe), can be obtained under mild conditions at room temperature and in green solvents (water, ethanol) through scalable synthesis methods. A solvent-free synthesis of a range of crystalline MOFs has been described. Usually the metal acetate and the organic proligand are mixed and ground up with a ball mill. Cu3(BTC)2 can be quickly synthesised in this way in quantitative yield.
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.