This is a working overview of Prohibited substance, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-01-12. Anything still debated is marked as such rather than presented as settled.
Legal status varies by country. In some places, cardarine is controlled under medicines or psychoactive substances laws; in others, it may be sold with minimal oversight as a research chemical. Customs agencies have intercepted shipments, and several national health agencies have issued warnings about products marketed for bodybuilding or performance enhancement. The lack of a standardized pharmaceutical supply means identity, purity, and contamination levels can differ widely between samples. These factors make cardarine a regulatory and public health concern rather than a conventional prescription drug.
Cardarine is a common name for GW501516, a synthetic compound first described in the 1990s as a selective agonist of the peroxisome proliferator-activated receptor delta. It was studied in preclinical models for metabolic and cardiovascular conditions, but it has not been approved as a medicine in the United States, Europe, or other major jurisdictions. Retail products labeled as cardarine are generally research chemicals or supplements, not pharmaceutical formulations. Because human safety and efficacy data remain limited, regulatory agencies treat it as an unapproved substance rather than a therapeutic product.
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.
| Property | Value | Notes |
|---|---|---|
| IUPAC name | {4-[({4-methyl-2-[4-(trifluoromethyl)phenyl]-1,3-thiazol-5-yl}methyl)sulfanyl]phenoxy}acetic acid | Systematic name for GW501516 |
| CAS Registry Number | 317318-70-0 | Unique identifier for the parent compound |
| Molecular formula | C21H18F3NO3S2 | Includes carbon, hydrogen, fluorine, nitrogen, oxygen, and sulfur |
| Molecular weight | 453.5 g/mol | Approximate value for the neutral form |
| Appearance | White to off-white powder | Typical description for purified laboratory material |
==== Absorption and bioavailability ==== The oral bioavailability of estradiol is very low. This is due to the fact that estradiol is poorly soluble in water, which limits its dissolution and absorption, and is additionally subject to extensive metabolism during the first pass through the intestines and liver. Estradiol is micronized and/or conjugated with an ester, as in estradiol valerate or estradiol acetate, to improve its oral bioavailability and potency. Micronization decreases the particle size of estradiol crystals and hence increases the surface area for absorption, thereby improving the rate and extent of absorption. In addition, there is an improvement in metabolic stability. Oral micronized estradiol consists of more than 80% of estradiol particles micronized to a size smaller than 20 μm in diameter, or to about 1 to 3 μm on average. All oral formulations of estradiol available today are micronized, and oral estradiol valerate tablets also seem to be micronized. Oral non-micronized estradiol and oral micronized estradiol do not appear to have ever been directly compared in a study. Both have been assessed independently however, and have been found to produce significant estrogenic effects. Micronization of other poorly water-soluble steroids such as spironolactone and norethisterone acetate has been found to increase their potency by several-fold.
Moreover, the PP opted for a greater alignment with the United States, which was immediately reflected in European policy, especially when in 2003 the debate on the draft European Constitution was opened, to which the Spanish government opposed by not accepting the distribution of votes proposed for the adoption of decisions in the European Councils. This policy of "international reaffirmation" was also reflected in the deterioration of relations with Morocco, which reached a peak of tension in the summer of 2002 on the occasion of the occupation by Moroccan gendarmes of the uninhabited Perejil Island, close to Ceuta, and which Spain considered under its sovereignty. Aznar's government decidedly supported the "war against terrorism" declared by President George W. Bush after the September 11 attacks in New York and Washington, so that when the United States started the Afghanistan war in October 2001 and the Iraq War in March 2003, it had his support despite the fact that in the second case the public opinion was mostly against it. Thus, four days after the beginning of the invasion of Iraq, the government decided to send a "joint humanitarian support unit", which arrived in Iraq one day after the fall of Baghdad, on April 9. Meanwhile, demonstrations against the war continued to take place ─ some led by the Socialist leader Rodríguez Zapatero.
== Further reading == Viana, Raquel V.; Wallis, Carole L. (2011). "3. Good clinical laboratory practice (GCLP) for molecular based tests used in diagnostic laboratories". In Akyar, Isin (ed.). Wide Spectra of Quality Control. BoD – Books on Demand. pp. 29–52. ISBN 978-953-307-683-6.
Trimipramine is a very potent antihistamine; it has the third highest affinity for the H1 receptor (Ki = 0.27 nM) after doxepin (Ki = 0.24 nM) and mirtazapine (Ki = 0.14 nM) among the TCAs and tetracyclic antidepressants (TeCAs). The TeCA mianserin (Ki = 0.40) and the TCA amitriptyline (Ki = 1.0) are also very potent H1 receptor antagonists, whereas other TCAs and TeCAs are less potent. These TCAs and TeCAs, including trimipramine, are far more potent than the standard antihistamine diphenhydramine (approximately 800 times for doxepin and 250 times for trimipramine), and are among the most potent antihistamines available. Trimipramine is also an antagonist of the H2 receptor with lower potency and has been found to be effective in the treatment of duodenal ulcers.
The therapeutic window is the amount of a medication between the amount that gives an effect (effective dose) and the amount that gives more adverse effects than desired effects. For instance, medication with a small pharmaceutical window must be administered with care and control, e.g. by frequently measuring blood concentration of the drug, since it easily loses effects or gives adverse effects.
Sources: en.wikipedia.org
The drug combination fenfluramine/phentermine, usually called fen-phen, is an anti-obesity medication that is no longer widely available. It was sold in the early 1990s, and utilized two anorectics. Fenfluramine was marketed by American Home Products (later known as Wyeth) as Pondimin, but was shown to cause potentially fatal pulmonary hypertension and heart valve problems, which eventually led to its withdrawal in 1997 and legal damages of over $13 billion. On the other hand, phentermine has side effects such as a fast heart beat, high blood pressure, trouble sleeping, dizziness, and restlessness. Fenfluramine acts as a serotonin releasing agent, phentermine as primarily a norepinephrine releasing agent. Phentermine also induces the release of serotonin and dopamine, although to a far lesser extent than it induces the release of norepinephrine.
=== Archaeobotanical record and ruderal habitat === The interaction between the Moche and this wild species is supported by its ecological behavior and archaeobotanical findings in the La Libertad Region. Solanum pimpinellifolium behaves as a ruderal plant, proliferating naturally and constantly along the edges of irrigation canals, ditches, and humid depressions built by pre-Hispanic agricultural engineers. Contemporary botanical and archaeological inventories have recorded stable populations of this wild tomato growing directly over the cultural contexts of major Moche political-religious centers, such as the El Brujo Arqueological Complex (in the Chicama Valley) and near the Huaca del Rosario (in Magdalena de Cao). This resource holds high scientific and historical value because Peru is a key center of origin for the tomato, hosting 14 of the world's 17 tomato species. Research by Peru's Ministry of the Environment indicates that roughly 90% of the genes in modern commercially cultivated tomatoes worldwide originate from these wild Andean relatives, which contributed high natural sugar levels and lycopene content to ancient diets.
==== Body composition and strength improvements ==== Anabolic steroids influence muscle fiber characteristics, affecting both the size and type of muscle fibers. This alteration significantly contributes to enhanced muscle strength and endurance. Anabolic-androgenic steroids (AAS) cause these changes by directly impacting the muscle tissue's cellular components. Studies have shown that these changes are not merely superficial but represent a profound transformation in the muscle's structural and functional properties. This transformation is a key factor in the steroids' ability to enhance physical performance and endurance. Body weight in men may increase by 2 to 5 kg as a result of short-term (<10 weeks) AAS use, which may be attributed mainly to an increase of lean mass. Animal studies also found that fat mass was reduced, but most studies in humans failed to show significant fat mass decrements. The effects on lean body mass have been shown to be dose-dependent. Both muscle hypertrophy and the formation of new muscle fibers have been observed. The hydration of lean mass remains unaffected by AAS use, although small increments of blood volume cannot be ruled out. The upper region of the body (thorax, neck, shoulders, and upper arm) seems to be more susceptible for AAS than other body regions because of predominance of ARs in the upper body. The largest difference in muscle fiber size between AAS users and non-users was observed in type I muscle fibers of the vastus lateralis and the trapezius muscle as a result of long-term AAS self-administration.
==== Nitrogen ==== Nitrogen gas (N2) makes up 78% of the atmosphere and is extremely well mixed over short time-scales, resulting in a homogenous isotopic distribution ideal for use as a reference material. Atmospheric N2 is commonly called AIR when being used as an isotopic reference. In addition to atmospheric N2 there are multiple N isotopic reference materials.
Sources: en.wikipedia.org
No. Major drug regulators have not approved GW501516 for treating any medical condition. Products sold as cardarine are typically unapproved research chemicals or supplements, so their contents and safety are not assured.
It is prohibited by the World Anti-Doping Agency as a hormone and metabolic modulator. Athletes who test positive for GW501516 can face sanctions, including suspensions and loss of results.
Cardarine is a common or trade-style name, while GW501516 is the research code for the same chemical entity. Some sources also use Endurobol or GSK-516. The names refer to the same compound, not distinct drugs.
No. Cardarine is a PPARδ agonist, while selective androgen receptor modulators act on androgen receptors. The two classes differ in receptor target and downstream effects.