This is a working overview of PPARδ agonist, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-03-30. Anything still debated is marked as such rather than presented as settled.
Cardarine can be detected in biological samples and product materials using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The method separates compounds by chromatography and identifies them by mass-to-charge transitions, allowing low-level detection in urine or blood. Sample preparation often involves enzymatic hydrolysis, solid-phase extraction, or protein precipitation. Certified reference materials and isotope-labeled internal standards improve quantification. Detection windows depend on metabolism, matrix, and assay sensitivity, so no single universal window applies.
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.
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.
| Property | Value | Notes |
|---|---|---|
| WADA classification | S4 Hormone and Metabolic Modulators | Prohibited at all times in sport. |
| Drug approval status | Not approved in major jurisdictions | No accepted therapeutic indication. |
| Common detection method | LC-MS/MS | Detects parent compound and metabolites. |
| Typical test matrix | Urine or blood | Urine is common in anti-doping testing. |
| Product labeling | Research chemical or supplement | Often not independently verified. |
Activation of PPARδ changes transcription of genes involved in fatty acid transport, mitochondrial function, and skeletal muscle fuel preference. In rodent studies, pharmacological PPARδ activation was associated with increased endurance and altered body composition. These findings generated interest in performance enhancement, but species differences and study designs limit direct extrapolation to humans. Small human trials were conducted in the 2000s and later discontinued. The extent to which cardarine produces similar metabolic or performance effects in people remains an open question.
The compound is typically described as a laboratory compound rather than a therapeutic product. Published reports have explored its role in lipid disorders, insulin sensitivity, and exercise metabolism, yet no major drug regulator has approved it for medical use. Commercial samples sold under the cardarine name may vary in purity and identity. Analytical confirmation is therefore necessary when the material is discussed in scientific or regulatory contexts. Its classification as a prohibited substance in sport further shapes how it is studied and reported.
GW501516 acts as a ligand for PPAR delta, a nuclear receptor that regulates transcription of genes involved in fatty acid oxidation and energy use. Activation of this receptor in skeletal muscle shifts metabolism toward fat burning in animal models. The compound does not burn fat directly; it changes gene expression over hours to days. Researchers study it to understand metabolic flexibility and exercise adaptation. Effects observed in rodents are not automatically expected in humans.
Preclinical research reported that GW501516 increased running endurance in mice and improved lipid profiles in some animal species. Early human trials explored effects on high-density lipoprotein cholesterol, triglycerides, and glucose handling, but the program was discontinued. Published human data are sparse and do not establish efficacy for any condition. Studies also examined PPAR delta in cancer biology, with conflicting findings across models. The relationship between receptor activation, tissue context, and disease risk remains an active area of investigation.
Anti-doping laboratories identify GW501516 and its metabolites using liquid chromatography-tandem mass spectrometry. Urine is the usual matrix, and detection can occur after the parent compound has cleared from blood. The exact detection window depends on dose, formulation, individual metabolism, and assay sensitivity. Because the compound is prohibited at all times, athletes are subject to testing in and out of competition. Analytical methods continue to improve as new metabolites and designer analogs are characterized.
Regulatory treatment varies, but cardarine is not approved as a medicine. Sports authorities list GW501516 as a prohibited substance, and it is banned at all times under the World Anti-Doping Agency code. Many countries restrict sales for human consumption, while online vendors market it as a research chemical. Such products may lack purity data, and their actual contents can differ from the label. Purchasing or possessing cardarine may carry legal consequences depending on jurisdiction. The compound is not a dietary supplement ingredient in regulated markets.
Clinical development stopped after rodent studies showed tumors at multiple sites. Whether those findings predict human cancer risk remains an open question, but they led sponsors to discontinue programs. Human safety data are limited to small, short-term studies that were not designed to assess cancer risk. Reported effects in those studies included changes in blood lipids, but the evidence is insufficient for medical use. Long-term consequences of nonmedical use are not well characterized. Questions about dose, duration, and individual susceptibility remain unresolved.
Cardarine is a common name for GW501516, an investigational compound developed in the 1990s for metabolic conditions. It acts as an agonist at peroxisome proliferator-activated receptor delta, a nuclear receptor involved in lipid and energy metabolism. The compound is frequently mislabeled as a selective androgen receptor modulator, or SARM, but its molecular target is different. GW501516 reached early clinical testing before development was discontinued. It has no approved therapeutic use in any country. The name cardarine is not a formal international nonproprietary name.
== Chemistry == Each amino acid has an amine group and a carboxylic group. Amino acids link to one another by peptide bonds which form through a dehydration reaction that joins the carboxyl group of one amino acid to the amine group of the next in a head-to-tail manner to form a polypeptide chain. The chain has two ends – an amine group, the N-terminus, and an unbound carboxyl group, the C-terminus. When a protein is translated from messenger RNA, it is created from N-terminus to C-terminus. The amino end of an amino acid (on a charged tRNA) during the elongation stage of translation, attaches to the carboxyl end of the growing chain. Since the start codon of the genetic code codes for the amino acid methionine, most protein sequences start with a methionine (or, in bacteria, mitochondria and chloroplasts, the modified version N-formylmethionine, fMet). However, some proteins are modified posttranslationally, for example, by cleavage from a protein precursor, and therefore may have different amino acids at their N-terminus.
I would guess if we had gone in there, we would still have forces in Baghdad today. We'd be running the country. We would not have been able to get everybody out and bring everybody home. And the final point that I think needs to be made is this question of casualties. I don't think you could have done all of that without significant additional US casualties, and while everybody was tremendously impressed with the low cost of the conflict, for the 146 Americans who were killed in action and for their families, it wasn't a cheap war.
== Applications == Enteropeptidase's specificity makes it an ideal tool in biochemical applications; a fusion protein containing a C-terminal affinity tag (such as poly-His) linked by this sequence can be cleaved by enteropeptidase to obtain the target protein following protein purification. On the converse, the N-terminal pro-sequence of proteases that must be cleaved prior to activation can be mutated to enable activation with enteropeptidase.
Sources: en.wikipedia.org
== Discovery == Studies conducted in the 1970s found that a series of N-formylmethionine-containing oligopeptides, including the most potent and best known member of this series, N-formylmethionine-leucyl-phenylalanine (fMLF or fMet-Leu-Phe), stimulated rabbit and human neutrophils by an apparent receptor-dependent mechanism to migrate in a directional pattern in classical laboratory assays of chemotaxis. Since these oligopeptides were produced by bacteria or synthetic analogs of such products, it was suggested that the N-formyl oligopeptides are important chemotactic factors and their receptors are important chemotactic factor receptors that act respectively as signaling and signal-recognizing elements to initiate inflammation responses in order to defend against bacterial invasion. Further studies defined a receptor for the N-formyl oligopeptides, formyl peptide receptor (FPR), so named based on its ability to bind and become activated by the oligopeptides. Two receptors where thereafter discovered and named FPR1 and FPR2 based on the similarity of their genes' predicted amino acid sequence to that of FPR rather than on any ability to bind or be activated by the formyl oligopeptides.
These studies both reported that all obvious symptoms of scurvy could be completely reversed by supplementation of only 10 mg a day. Treatment of scurvy can be with vitamin C-containing foods or dietary supplements or injection.
Topical beta-adrenergic receptor antagonists, such as timolol, levobunolol, and betaxolol, decrease aqueous humor production by the epithelium of the ciliary body. Alpha2-adrenergic agonists, such as brimonidine and apraclonidine, work by a dual mechanism, decreasing aqueous humor production and increasing uveoscleral outflow. Less-selective alpha agonists, such as epinephrine, decrease aqueous humor production through vasoconstriction of ciliary body blood vessels, useful only in open-angle glaucoma. Epinephrine's mydriatic effect, however, renders it unsuitable for closed-angle glaucoma due to further narrowing of the uveoscleral outflow (i.e., further closure of the trabecular meshwork, which is responsible for the absorption of aqueous humor). Miotic agents (parasympathomimetics), such as pilocarpine, work by contraction of the ciliary muscle, opening the trabecular meshwork and allowing increased outflow of the aqueous humor. Echothiophate, an acetylcholinesterase inhibitor, is used in chronic glaucoma. Carbonic anhydrase inhibitors, such as dorzolamide, brinzolamide, and acetazolamide, lower secretion of aqueous humor by inhibiting carbonic anhydrase in the ciliary body. Each of these medicines may have local and systemic side effects. Wiping the eye with an absorbent pad after the administration of eye drops may result in fewer adverse effects. Initially, glaucoma drops may reasonably be started in either one or in both eyes.
The cause is genetic mosaicism; that is, some of, or most of, the germ cells of one parent have a dominant form of OI, but not enough of their somatic cells do to cause symptoms or obvious disability in the parent—the parent's different cells have two (or more) sets of slightly different DNA. It has been clinically observed that ≈5–10% of cases of OI types II and III are attributable to genetic mosaicism.
Sources: en.wikipedia.org
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.
Legality varies by country and context. It lacks marketing approval as a medicine in major countries. Sports organizations prohibit its use at all times.
A certificate of analysis may report identity, purity, and testing methods for a specific batch. It does not guarantee safety or legal status. Independent verification can confirm whether the material matches the label.
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.