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Background And Research Context — Worked Examples

By Editorial Desk · published 2026-01-26 · last reviewed 2026-02-25 · Faq

A practical reference on GW501516: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.

This page was last updated on 2026-02-25 and is reviewed periodically as new material appears.

Background and Research Context

In laboratory settings, cardarine is studied as a tool compound for probing PPARδ biology. Published experiments often use cell cultures, rodent models, or isolated tissues. Some investigations focus on metabolic effects, while others assess potential risks such as carcinogenicity observed in long-term animal studies. Because human trials are sparse, most knowledge comes from preclinical work and adverse event reports. Scientific literature frequently notes the gap between animal findings and human outcomes. The compound is not a dietary supplement and is not intended for human consumption.

Cardarine is a common name for GW501516, a synthetic compound developed in the 1990s through research collaborations involving GlaxoSmithKline. It belongs to a class of molecules known as peroxisome proliferator-activated receptor delta agonists. Early studies explored its effects on lipid metabolism and energy expenditure in animal models. The compound was never approved as a human medicine, and clinical development was discontinued. In the years since, it has appeared in fitness and bodybuilding communities as a performance-enhancing substance. Regulatory agencies classify it as an unapproved drug.

Mechanism and Research Context

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.

Cardarine at a glance

PropertyValueNotes
CAS Registry Number317318-70-0Unique identifier for the compound.
Chemical classPPARδ agonistSynthetic ligand for peroxisome proliferator-activated receptor delta.
AppearanceWhite to off-white solidTypical form of research-grade material.
SolubilitySoluble in DMSO and ethanolPoorly soluble in water.
Typical storage-20°CRecommended for long-term storage of stock solutions.

Background and Regulatory History

Regulatory bodies treat GW501516 as a prohibited substance in competitive sport. The World Anti-Doping Agency added it to the prohibited list, and it falls under classes covering metabolic modulators and hormone-related agents. It is not approved by drug regulators for human use, and it is not a lawful dietary supplement. Products sold under the cardarine name may contain unlisted ingredients or different compounds. Because no approved product exists, quality and identity are not guaranteed by pharmaceutical manufacturing standards.

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.

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Preclinical Findings and Safety Signals

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.

Mechanism and Laboratory Detection

Laboratory handling focuses on identity, purity, and stability. Reference standards are typically stored cold and dry, protected from light, because solutions can degrade over time. Analytical checks may use high-performance liquid chromatography with ultraviolet detection or mass spectrometry. Impurities and related substances can be separated chromatographically and compared with a known standard. Because cardarine is not an approved drug, compendial monographs are absent, and laboratories often rely on in-house methods. Reported purity varies among unregulated products and should not be assumed from a label.

GW501516 binds and activates PPARδ, a nuclear receptor that influences transcription of genes involved in fatty acid oxidation and energy use. Activation shifts some metabolic pathways in preclinical models, which is why the compound has been studied for lipid disorders and exercise-related endpoints. The exact downstream effects in humans are incompletely mapped. PPARδ is expressed in many tissues, including skeletal muscle, liver, and adipose tissue, so broad activation may have varied consequences. Researchers continue to examine how selective or partial activation might alter the balance between benefits and risks.

Cardarine Identity and Mechanism

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.

Background from the literature

In the United Kingdom, it is a criminal offence to sell, supply, or import any medicinal product containing kava for human consumption. It is legal to possess kava for personal use or to import it for purposes other than human consumption (e.g., for animals). Until August 2018, Poland was the only EU country with an "outright ban on kava" and where the mere possession of kava was prohibited and may have resulted in a prison sentence. Under the new legislation, kava is no longer listed among prohibited substances and it is therefore legal to possess, import, and consume the plant, but it remains illegal to sell it within Poland for the purpose of human consumption. In the Netherlands the ban was never lifted, and it is still prohibited to prepare, manufacture, or trade kava or goods containing kava. Due to safety concerns, including reports of hepatotoxicity and limitations in clinical evidence, the Committee on Herbal Medicinal Products (HMPC) concluded in 2017 that the benefit-risk balance for the oral use of kava in the treatment of anxiety disorders is unfavorable, and therefore a European Union herbal monograph could not be established.

The US Food and Drug Administration granted the application for datopotamab deruxtecan priority review and breakthrough therapy designations. Efficacy was evaluated in TROPION-Breast02 (NCT05374512), a multicenter, open-label, randomized trial of 644 participants with unresectable or metastatic triple-negative breast cancer who had not received prior chemotherapy or other systemic anti-cancer therapy for unresectable or metastatic breast cancer and who were not candidates for PD-1/PD-L1 inhibitor therapy. Participants were excluded for a history of ILD/pneumonitis requiring treatment with steroids, ongoing ILD/pneumonitis, or clinically significant corneal disease at screening. Randomization was stratified by geographical region (United States, Canada and Europe, or rest of world), PD-L1 status (positive or negative) and disease-free interval history (de novo or ≤12 months or >12 months). Participants were randomized (1:1) to receive either datopotamab deruxtecan-dlnk (N=323) or investigator's choice of chemotherapy (N=321); paclitaxel (28%), nab-paclitaxel (54%), capecitabine (2.2%), eribulin (11%) or carboplatin (4.7%).

==== Reactions of tyrosines ==== Tyrosine residues are relatively unreactive; therefore they have not been a popular targets for bioconjugation. Recent development has shown that the tyrosine can be modified through electrophilic aromatic substitutions (EAS) reactions, and it is selective for the aromatic carbon adjacent to the phenolic hydroxyl group. This becomes particularly useful in the case that cysteine residues cannot be targeted. Specifically, diazonium effectively couples with tyrosine residues (diazonium salt shown as reagent in the first reaction in Figure 3 below), and an electron withdrawing substituent in the 4-position of diazonium salt can effectively increase the efficiency of the reaction. Cyclic diazodicarboxyamide derivative like 4-Phenyl-1,2,4-triazole-3,5-dione (PTAD) were reported for selective bioconjugation on tyrosine residues (the second reaction in Figure 3 below). A three-component Mannich-type reaction with aldehydes and anilines (the last reaction in Figure 3) was also described to be relatively tyrosine-selective under mild optimised reaction conditions.

The absolute speed record for wind at Le Havre – Cap de la Heve was recorded on 16 October 1987 at 180 kilometres per hour (112 miles per hour). The main natural hazards are floods, storms, and storm surges. The lower town is subject to a rising water table. The lack of watercourses within the commune prevents flooding from overflows. Le Havre's beach may rarely experience flooding known as "flooding from storms". These are caused by the combination of strong winds, high waves, and a large tidal range.

Sources: en.wikipedia.org

Further detail

=== Types === A to I RNA editing is catalyzed by a family of adenosine deaminases acting on RNA (ADARs) that specifically recognize adenosines within double-stranded regions of pre-mRNAs and deaminate them to inosine. Inosines are recognised as guanosine by the cell's translational machinery. There are three members of the ADAR family ADARs 1-3 with ADAR 1 and ADAR 2 being the only enzymatically active members. ADAR3 is thought to have a regulatory role in the brain. ADAR1 and ADAR 2 are widely expressed in tissues while ADAR 3 is restricted to the brain. The double stranded regions of RNA are formed by base-pairing between residues in the close to region of the editing site with residues usually in a neighboring intron but can be an exonic sequence. The region that base pairs with the editing region is known as an Editing Complentary Sequence (ECS). It is thought that the pre-mRNA of IGFBP7 is a substrate for ADAR1 based on the expression spectrum of the editing enzyme.

=== Reform and further enlargement === East Germany joined on 3 October 1990 through reunification with West Germany. In the 1990s, several European countries, now members of the European Union, expressed their willingness to join the Organisation. In 1995, Cyprus applied for membership, but according to the Cypriot government, it was vetoed by Turkey. In 1996, Estonia, Latvia, and Lithuania signed a Joint Declaration expressing willingness to become members of the OECD, and Slovenia also applied for membership that same year. In 2005, Malta applied to join the Organisation. The EU is lobbying for the admission of all EU member states. Romania reaffirmed in 2012 its intention to become a member of the Organisation through the letter addressed by Romanian Prime Minister Victor Ponta to OECD Secretary-General José Ángel Gurría. In September 2012, the government of Bulgaria confirmed it would apply for membership before the OECD Secretariat. The OECD established a working group headed by ambassador Seiichiro Noboru to work out a plan for the enlargement with non-members.

Coral reefs are under stress around the world. In particular, coral mining, agricultural and urban runoff, pollution (organic and inorganic), overfishing, blast fishing, disease, and the digging of canals and access into islands and bays are localized threats to coral ecosystems. Broader threats are sea temperature rise, sea level rise and pH changes from ocean acidification, all associated with greenhouse gas emissions. In 1998, 16% of the world's reefs died as a result of increased water temperature. Approximately 10% of the world's coral reefs are dead. About 60% of the world's reefs are at risk due to human-related activities. The threat to reef health is particularly strong in Southeast Asia, where 80% of reefs are endangered. Over 50% of the world's coral reefs may be destroyed by 2030; as a result, most nations protect them through environmental laws. In the Caribbean and tropical Pacific, direct contact between ~40–70% of common seaweeds and coral causes bleaching and death to the coral via transfer of lipid-soluble metabolites. Seaweed and algae proliferate given adequate nutrients and limited grazing by herbivores such as parrotfish. Water temperature changes of more than 1–2 °C (1.8–3.6 °F) or salinity changes can kill some species of coral. Under such environmental stresses, corals expel their Symbiodinium; without them, coral tissues reveal the white of their skeletons, an event known as coral bleaching.

== Side effects == Side effects of tavapadon may include nausea, headache, dizziness, fatigue or asthenia, dysgeusia, vomiting, dry mouth, and anxiety. Other potential but less common side effects include hypotension, orthostatic hypotension, impulsive control problems, compulsive behaviors, hallucinations, psychotic-like behaviors, and dyskinesia.

=== Secretome alters with exercise === A study examined the biopsies of a thigh skeletal muscle (vastus lateralis muscle) of eight 23-year old, originally sedentary, Caucasian males. Biopsies were taken both before and after a six-week long endurance exercise training program. The exercise consisted of riding a stationary bicycle for one hour, five days a week for six weeks. Of the 13,108 genes with detected expression in the muscle biopsies, 641 genes were upregulated after endurance training and 176 genes were downregulated. Of the 817 total altered genes, 531 were identified as being in the secretome by either or both of UniProt or ExoCarta, or else by studies investigating the secretome of muscle cells. Because many of the exercise-regulated genes are identified as secreted, this indicates that much of the effect of exercise has an endocrine rather than metabolic function. The main pathways found to be affected by secreted exercise-regulated proteins were related to cardiac, cognitive, kidney and platelet functions.

Sources: en.wikipedia.org

Background from the literature

==== Somatostatin analogues ==== The primary medical treatment of acromegaly is to use somatostatin analogues – octreotide (Sandostatin) or lanreotide (Somatuline). Somatostatin analogues are also sometimes used to shrink large tumors before surgery. Because octreotide inhibits gastrointestinal and pancreatic function, long-term use causes digestive problems such as loose stools, nausea, and gas in one-third of people. In addition, approximately 25 percent of people with acromegaly develop gallstones, which are usually asymptomatic. In some cases, octreotide treatment can cause diabetes because somatostatin and its analogues can inhibit the release of insulin. With an aggressive adenoma that is not able to be operated on, there may be a resistance to octreotide in which case a second-generation SSA, pasireotide, may be used for tumor control. However, insulin and glucose levels should be carefully monitored as pasireotide has been associated with hyperglycemia by reducing insulin secretion.

=== Diagnostic criteria === An international group created a set of criteria for the diagnosis of primary Sjögren's disease in 2016 based on consensus around previous guidelines from the American College of Rheumatology (ACR) and European League Against Rheumatism (EULAR), which became known as the ACR-EULAR criteria. Although used primarily for recruitment into clinical trials, the criteria were shown to be effective in diagnosing Sjögren's by a 2025 Swedish cohort study. Per the ACR-EULAR criteria, a person with previously reported dry eye or dry mouth symptoms (including if responding positively to a short questionnaire) has SjD if they have a score of at least 4 when considering the following items:

== Treatment == Disease progression may be slowed with immunosuppressives and other medications, and esophageal reflux, pulmonary hypertension and Raynaud phenomenon may benefit from symptomatic treatment. However, there is no cure for this disease as there is no cure for scleroderma in general.

The female movement of the 1960s, combined with Title IX and the all around fitness revolution, gave birth to new alternative perspectives of feminine beauty that included an athletic physique of toned muscle. This athletic physique was found in various popular media outlets such as fashion magazines. Female bodybuilders changed the limits of traditional femininity as their bodies showed that muscles are not only just for men.

Sources: en.wikipedia.org

Frequently asked questions

What is cardarine?

Cardarine is a common name for GW501516, a synthetic PPARδ agonist developed for research. It has not been approved as a medication in any country. It is classified as an unapproved drug and a prohibited substance in sport.

Is cardarine a steroid?

No. Cardarine is not an anabolic steroid; it belongs to a different chemical class that targets PPARδ. Steroids act primarily through androgen receptors, while cardarine acts through a nuclear receptor involved in metabolism.

What did animal studies find?

Some rodent studies reported increased endurance and changes in fat metabolism after cardarine exposure. Long-term studies in animals also raised concerns about cancer in certain tissues. Human trial data are limited, so these findings cannot be directly translated to people.

How does cardarine work in the body?

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.

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