This is a working overview of LC-MS/MS, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-12-25. 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.
Laboratory studies have examined GW501516 in cell cultures and rodents for conditions such as dyslipidemia, insulin resistance, and obesity. Some trials in humans were initiated, but development was discontinued after preclinical findings raised concerns about cancer in certain models. Those findings do not prove that the compound causes cancer in people, but they contributed to regulatory caution. Later reviews often describe the evidence as preliminary and insufficient for assessing long-term safety.
In the fitness and bodybuilding literature, cardarine is frequently discussed as an endurance agent or fat-loss compound, although such claims are not supported by robust clinical evidence. Online descriptions often mix animal data, user anecdotes, and marketing language. Researchers who study PPARδ agonists distinguish between receptor activation in controlled experiments and unsupervised use of unverified products. The latter introduces unknown purity, dose, and interactions, making reported experiences difficult to interpret scientifically.
GW501516 acts as an agonist at peroxisome proliferator-activated receptor delta, a nuclear receptor involved in transcription of genes related to lipid handling and energy use. Activation of PPARδ can shift skeletal muscle toward greater fatty acid oxidation in animal models, which is one reason it drew interest for metabolic disease and exercise research. The exact downstream effects depend on tissue, species, dose, and duration. Human data are sparse, so many proposed benefits remain hypotheses rather than established clinical outcomes.
| 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. |
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.
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.
Published literature on cardarine includes in vitro assays, rodent experiments, and a small number of human studies. Reports describe effects on exercise capacity and lipid metabolism in animals, while human evidence is sparse. Many online descriptions present the compound as a proven endurance aid, a claim not supported by regulatory approval or large clinical trials. Analytical studies focus on identifying the parent compound and its metabolites in biological samples. Important uncertainties include species differences, dose-response relationships, and the relevance of rodent tumor findings to humans.
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.
== P == P42 MAP kinase -p53 - pancreatic polypeptide - parathyroid hormone receptor - partial pressure - passive transport - Pauling scale - PCR - peptide - peptide bond - peptide elongation factor - peptide elongation factor tu - peptide fragment - peptide initiation factor - peptide receptor - peptide termination factor - peripheral membrane protein - pesticide - pH - phage display - pharmaceutical - pharmacist - pharmacology - phenol - phenotype - phenyl group - phenylalanine - Philadelphia chromosome - phospholipid - phospholipid bilayer - phosphopeptide - phosphoprotein - phosphorus - phosphorylation - phosphoserine - phosphothreonine - phosphotyrosine - photobiology - photolysis - photophosphorylation - photoreceptor - photorespiration - photosynthesis - photosystem I - photosystem II - phototransduction - phylogenetics - phylogeny - physical chemistry - physiology - phytohaemagglutinin - pituitary hormone receptor - pituitary hormone-regulating hormone receptor - plant protein - plasma membrane - plasmid - plasmin - plasminogen - platelet glycoprotein GPIb-IX complex - platelet membrane glycoprotein - platelet-derived growth factor - platelet-derived growth factor receptor - polymer - polymerase chain reaction - polymerization - polymyxin - polymyxin B - polyomavirus transforming antigen - polypeptide - polysaccharide - porphyrin - Posttranslational modification - potassium - potassium channel - potential energy - pregnancy proteins - primary nutritional groups - primary structure - primer - prion - progesterone receptor - prokaryote - prolactin - prolactin receptor - proline - promoter - prostaglandin e receptor - prostaglandin receptor - protein - protein biosynthesis - Protein Data Bank - protein design - protein expression - protein folding - protein isoform - protein nuclear magnetic resonance spectroscopy - protein P16 - protein P34cdc2 - protein precursor - protein structure prediction - protein subunit - protein synthesis - protein targeting - protein translocation - protein-tyrosine kinase - protein-tyrosine-phosphatase - proteinoid - proteomics - protirelin - proto-oncogene - proto-oncogene proteins - proto-oncogene protein C-kit - proto-oncogene proteins c-abl - proto-oncogene proteins c-bcl-2 - Proto-oncogene proteins c-fos - proto-oncogene proteins c-jun - proto-oncogene proteins c-mo - proto-oncogene proteins c-myc - proto-oncogene proteins c-raf - proton - proton pump - protozoan proteins - purine - purinergic P1 receptor - purinergic P2 receptor - purinergic receptor - pyridine - pyrimidine - pyruvate - pyruvate oxidation
=== Phase 2 === 7-Oxoprasterone (7-keto-DHEA; HBL-9001; HL-9001; At-Ease) – undefined mechanism of action (immunomodulator) [4] [5] Amdiglurax (ALTO-100; NSI-189) – unknown mechanism of action (hippocampal neurogenesis stimulant and indirect brain-derived neurotrophic factor (BDNF) modulator) [6] [7] BI-1358894 – transient receptor potential cation channel TRPC4 and TRPC5 inhibitor [8] Cannabidiol (A-1002-N5S; CBD; Nantheia™) – cannabinoid, various actions [9] CORT-108297 (ADS-108297) – glucocorticoid receptor antagonist [10] Dronabinol (BX-1) – cannabinoid CB1 and CB2 receptor agonist [11] Iloperidone (Fanapt; Fanaptum; Fiapta; HP-873; ILO-522; VYV-683; Zomaril) – atypical antipsychotic (non-selective monoamine receptor modulator) [12] Ketamine intranasal (Ereska; PMI-100; PMI-150; SLS-002; TUR-002) – NMDA receptor antagonist and dissociative hallucinogen [13] Lithium cocrystal (AL-001; LiProSal; lithium salicylate/L-proline cocrystal) – undefined mechanism of action and mood stabilizer (improved formulation of lithium) [14] Methylone (MDMC; TSND-201) – serotonin–norepinephrine–dopamine releasing agent and entactogen Midomafetamine/citalopram (MDMA/citalopram) – serotonin–norepinephrine–dopamine releasing agent, weak serotonin 5-HT2 receptor agonist, and entactogen followed by a selective serotonin reuptake inhibitor Psilocybin (COMP-360; COMP360) – non-selective serotonin receptor agonist, serotonin 5-HT2A receptor agonist, and psychedelic hallucinogen [15] Psilocybin (MYCO-001, MYCO-003) – non-selective serotonin receptor agonist, serotonin 5-HT2A receptor agonist, and psychedelic hallucinogen [16] Soclenicant (BNC-210; IW-2143) – α7-nicotinic acetylcholine receptor antagonist [17] SRX-246 (API-246) – vasopressin V1A receptor antagonist [18] Xenon (NBTX-001) – NMDA receptor antagonist [19]
RTI-5152-12, or WW-12 (in patent), is a synthetic small-molecule agonist of the atypical chemokine receptor ACKR3 (CXCR7) that was derived from the naturally occurring alkaloid conolidine. RTI-5152-12 has 15-fold improved potency towards ACKR3 relative to conolidine. ACKR3 is a novel opioid receptor which functions as a broad-spectrum trap or scavenger for endogenous opioid peptides, including enkephalins, dynorphins, and nociceptin. The receptor acts as a negative modulator of the opioid system by decreasing the availability of opioid peptides for their classical receptors like the μ-opioid receptor. Ligands of ACKR3, by competitively displacing endogenous opioid peptides from ACKR3, can potentiate the actions of these endogenous opioids and produce effects like analgesia and anxiolysis in animals. RTI-5152-12 is being developed as a potential pharmaceutical drug and, as of December 2021, is in the preclinical stage of development for treatment of pain. The chemical structure was not disclosed until a patent was published in June 2022.
=== Comorbidities === The condition is strongly associated with or caused by type 2 diabetes, insulin resistance, and metabolic syndrome (defined as at least three of the five following medical conditions: abdominal obesity, high blood pressure, high blood sugar, high serum triglycerides, and low serum high-density lipoprotein). It is also associated with:
Sources: en.wikipedia.org
=== Safety === By definition, a first-in-class drug does not have the safety evidence from analogous products that not-first-in-class drugs would have. However, a study investigating recalls and warnings in relation to first-in-class drugs approved between 1997 and 2012 by Health Canada has found that first-in-class drugs actually have a more favourable benefit-to-harm ratio.
Lungs can be affected by a number of diseases and disorders. Pulmonology is the medical speciality that deals with respiratory diseases involving the lungs and respiratory system. Cardiothoracic surgery deals with surgery of the lungs including lung volume reduction surgery, lobectomy, pneumectomy and lung transplantation.
== Function == This region functions to provide mechanical support for the articular cartilage. It serves primarily as an intermediate protective layer for tissues undergoing continuous mechanical loading. The fibril network distributes these stresses away from the chondrocyte membrane. Proteoglycan aggregates create osmotic swelling pressure that resists compression, while densely woven collagen fibrils confer tensile strength. The territorial matrix is also involved in signal transduction and nutrient exchange within the cartilage. The cartilage matrix lacks blood vessels, so nutrient and waste transport may only occur through diffusion directly through the extracellular matrix. The territorial matrix serves as a boundary layer, selectively permeable to the molecules necessary for chondrocyte. In result, the structure and composition of the territorial matrix directly influences the metabolism and function of the cells it protects. The territorial matrix also has an important role in mechanotransduction, the conversion of physical forces into biochemical signals. The mechanical movement of the territorial matrix changes ion concentrations, fluid flow, and strain on fibrils, all leading to various cellular responses like synthesis of matrix components or degradation. Mechanical stresses lead to adaptation and ultimately cartilage homeostasis; proper functioning of these signaling pathways are essential.
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.
It binds and activates PPARδ, a nuclear receptor that influences gene expression related to fatty acid metabolism and energy balance. This mechanism has been studied mainly in animals and cell models, not established as a safe human therapy.