If you have been reading about PPARδ agonist and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Cardarine is a common name for GW501516, also GW-1516, a synthetic compound developed as a peroxisome proliferator-activated receptor delta (PPARδ) agonist. It belongs to a class of agents that modulate gene transcription related to lipid and energy metabolism. The compound was studied in preclinical and early clinical research for metabolic and cardiovascular conditions, but it did not progress to approved therapeutic use. Its name appears in fitness and sports contexts despite not being approved as a drug.
PPARδ is a nuclear receptor that influences transcription of genes involved in fatty acid oxidation, lipid transport, and energy homeostasis. GW501516 binds and activates this receptor with high selectivity relative to PPARα and PPARγ in laboratory assays. Activation alters expression of target genes in skeletal muscle, liver, and adipose tissue in animal models. The exact clinical consequences of these changes in humans remain incompletely characterized, and observed effects in animals do not establish therapeutic benefit or safety.
| 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. |
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 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.
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.
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.
N-Formylmethionine (fMet, HCO-Met, For-Met) is a derivative of the amino acid methionine in which a formyl group has been added to the amino group. It is specifically used for initiation of protein synthesis from bacterial and organellar genes, and may be removed post-translationally. fMet plays a crucial part in the protein synthesis of bacteria, mitochondria and chloroplasts. It is not used in cytosolic protein synthesis of eukaryotes, where eukaryotic nuclear genes are translated. It is also not used by Archaea. In the human body, fMet is recognized by the immune system as foreign material, or as an alarm signal released by damaged cells, and stimulates the body to fight against potential infection.
== Contraindications == Contraindications are severe respiratory or liver impairment and acute alcoholism. There are limited accounts of cross-reactivity with opioids, but there is a possibility. Serious central nervous system (CNS) and respiratory depression may also occur with concurrent use of CNS depressants, ingesting alcohol, or other CNS-depressing factors while on buprenorphine/naloxone.
N,O-Didesmethyltramadol (tramadol metabolite M5) is an opioid derivative which is one of two active metabolites of the opioid analgesic medication tramadol. It is many times less potent than the other active metabolite O-Desmethyltramadol but is still more potent as a mu opioid receptor agonist than tramadol itself, unlike the other metabolites N-desmethyltramadol, N,N-didesmethyltramadol, and N,N,O-tridesmethyltramadol which are entirely without opioid activity. As with tramadol and O-desmethyltramadol it is found as a mixture of the (1S,2S)- and (1R,2R)-enantiomers, although the separate enantiomers of N,O-didesmethyltramadol have not been studied individually. It is specifically listed as a Schedule I drug in Canada, presumably due to concerns it may be subject to abuse as a designer drug in a similar manner to other opioid active metabolites such as O-desmethyltramadol and nortilidine.
Sources: en.wikipedia.org
=== In genetic disorders === Many genetic disorders involve hereditary defects in receptor genes. Often, it is hard to determine whether the receptor is nonfunctional or the hormone is produced at decreased level; this gives rise to the "pseudo-hypo-" group of endocrine disorders, where there appears to be a decreased hormonal level while in fact it is the receptor that is not responding sufficiently to the hormone.
Iodine-131 (131I) is a beta-emitting isotope with a half-life of 8.0249 days, and comparatively energetic (0.61 MeV) beta radiation, which penetrates 0.6 to 2.0 mm from the site of uptake. This beta radiation can be used for the destruction of thyroid nodules or hyperfunctioning thyroid tissue and for elimination of remaining thyroid tissue after surgery for the treatment of Graves' disease. The purpose of this therapy, which was first explored by Dr. Saul Hertz in 1941, is to destroy thyroid tissue that could not be removed surgically. In this procedure, 131I is administered either intravenously or orally following a diagnostic scan. This procedure may also be used, with higher doses of radio-iodine, to treat patients with thyroid cancer. The 131I is taken up into thyroid tissue and concentrated there. The beta particles emitted by the radioisotope destroys the associated thyroid tissue with little damage to surrounding tissues (more than 2.0 mm from the tissues absorbing the iodine). Due to similar destruction, 131I is the iodine radioisotope used in other water-soluble iodine-labeled radiopharmaceuticals (such as MIBG) used therapeutically to destroy tissues. The high energy beta radiation (up to 606 keV) from 131I causes it to be the most carcinogenic of the iodine isotopes.
The importance of membrane technology is growing in the field of environmental protection (Nano-Mem-Pro IPPC Database). Even in modern energy recovery techniques, membranes are increasingly used, for example in fuel cells and in osmotic power plants.
Sources: en.wikipedia.org
=== Silicone oils === The most common silicone oils used in diffusion pumps are trisiloxanes, which contain the chemical group Si-O-Si-O-Si, to which various phenyl groups or methyl groups are attached. These are available as the so-called 702 and 703 blends, which were formerly manufactured by Dow Corning. These can be further separated into 704 and 705 oils, which are made up of the isomers of tetraphenyl tetramethyl trisiloxane and pentaphenyl trimethyl trisiloxane respectively.
=== Post-embryonic retention === In most vertebrates, the notochord develops into secondary structures. In other chordates, the notochord is retained as an essential anatomical structure. The evolution of the notochord within the phylum Chordata is considered in detail by Holland and Somorjai (2020). Vertebrates now have spines so they do not need a notochord. The following organisms retain a post-embryonic notochord:
A mastiff is a large and powerful type of dog. Mastiffs are among the largest dogs, and typically have a short coat, a long low-set tail and large feet; the skull is large and bulky, the muzzle broad and short (brachycephalic) and the ears drooping and pendant-shaped. European and Asian records dating back 3,000 years show dogs of the mastiff type. Mastiffs have historically been guard dogs, protecting homes and property, although throughout history they have been used as hunting dogs, war dogs and for blood sports, such as dog fighting, bull-baiting, bear-baiting, and even lion-baiting.
In addition to non-viral delivery methods, RNA viruses have been engineered to achieve similar immunological responses. Typical RNA viruses used as vectors include retroviruses, lentiviruses, alphaviruses and rhabdoviruses, each of which can differ in structure and function. Clinical studies have utilized such viruses on a range of diseases in model animals such as mice, chicken and primates.
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.
Cardarine is commonly known as GW501516 or GW-1516. These names refer to the same synthetic compound. It is not a brand-name approved medicine.