This is a working overview of fatty acid oxidation, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-05-16 and is reviewed periodically as new material appears.
Early clinical research explored GW501516 for lipid disorders, obesity, and diabetes. Some short-term human studies reported changes in HDL cholesterol, LDL cholesterol, and triglycerides. The development program was discontinued after rodent studies showed dose-dependent tumor formation in multiple tissues, including liver, bladder, stomach, and skin. These findings raised concerns about long-term cancer risk in humans. Because human exposure data are limited, the clinical significance of the rodent tumors remains uncertain.
Literature on cardarine often separates receptor pharmacology from toxicology. Mechanistic papers describe PPARδ activation and gene expression changes, while safety assessments focus on carcinogenicity and species differences. Questions remain about whether rodent tumors arise through PPARδ-dependent or off-target mechanisms. Another open area is how human metabolism and exposure compare with those in animal studies. Analytical methods such as liquid chromatography–mass spectrometry are used to confirm identity in biological and product samples.
Handling and quality assessment of cardarine reference material follow general laboratory practices for poorly characterized compounds. It typically appears as a white to off-white powder and is sparingly soluble in water but soluble in organic solvents such as dimethyl sulfoxide and ethanol. Storage recommendations usually specify a cool, dry, dark place, with long-term storage at low temperature and desiccation. Purity may be checked by high-performance liquid chromatography with ultraviolet detection, while identity is confirmed by mass spectrometry and nuclear magnetic resonance. No pharmacopeial monograph exists, so reported purity and stability depend on the supplier’s methods.
GW501516 acts as a selective agonist at PPARδ, a nuclear receptor that regulates transcription of genes involved in lipid handling and energy metabolism. Activation of PPARδ in preclinical models increases fatty acid oxidation, mitochondrial biogenesis, and exercise endurance in rodents. These effects have made the compound a subject of metabolic research and also a target for sport anti-doping rules. In humans, however, controlled studies are limited, and whether similar endurance or metabolic changes occur at tolerated exposures remains an open question. The receptor’s broad tissue distribution also means downstream effects may vary by organ and condition.
| Property | Value | Notes |
|---|---|---|
| Primary target | PPARδ | Nuclear receptor; not androgen receptor |
| Studied indications | Dyslipidemia; obesity; diabetes | Early clinical research; development discontinued |
| Rodent toxicity | Tumor formation in multiple tissues | Dose-dependent findings in some studies |
| Human approval | None | No approved therapeutic use |
| Typical analytical method | LC-MS/MS | Used for identity and quantification |
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.
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.
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.
Safety discussions about cardarine frequently cite rodent carcinogenicity findings reported in the 2000s. In those studies, treated animals developed tumors at multiple sites, leading sponsors to discontinue clinical development. The relevance of these findings to humans has not been resolved, but they are a major reason the compound is not approved. Current literature emphasizes uncertainty about long-term effects and the risks of unregulated use. Regulators and health agencies have not established a safe human exposure level.
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 collapse of birthrates among blacks and (non-white) Hispanics, down 50%, was largely responsible for this development. However, their birthrates remained, on average, twice as high as those of their white counterparts. The birth rates of teenage Asians and Pacific Islanders were even lower, about half that of whites. In a 2014 paper, economists Melissa S. Kearney and Phillip B. Levine howed that popular TV programs depicting the reality of teenage parenthood, such as MTV's 16 and Pregnant and its Teen Mom sequels, have played a significant role in the reduction of teenage childbearing. Researchers from the Guttmacher Institute showed that the fall in teenage birthrates is likely not due to terminated pregnancies. The number of abortions remained the same or decreased in all U.S. states except for Vermont. This contradicts the historically negative correlation between birthrates and abortions. Modern youths also have better access to contraception than did their predecessors when they were at the same age. A CDC analysis found that the rates of teens using a long-acting and reversible method of contraception, such as an intrauterine device (IUD), jumped from 0.4% in 2005 to 7.1% in 2013. The teen birthrate continues to fall in the late 2010s, down to 17.4 births per 1000 in 2018. In 2022, it fell to 13.5, the lowest on record.
=== Psoriasis === In psoriasis Th22 cells have been causally linked to pathological processes. In patients with psoriasis the levels of Th22 cells and interleukin-22 (IL-22) were increased. High levels of interleukin-22 (IL-22) together with interleukin-6 (IL-6) can induce the expression of antimicrobial proteins (AMPs), and stimulate the keratinocytes to secrete proinflammatory mediators and chemokines in the skin. In addition, it can also inhibit keratinocyte differentiation and inhibit the normal skin healing process.
Nicotinamide adenine dinucleotide kinase 2, mitochondrial (NADK2), is a mitochondrial enzyme encoded by the human NADK2 gene. In eukaryotes it maintains the mitochondrial NADP(H) pool by phosphorylating NAD+ and NADH. NADPH plays a central role in mitochondrial metabolism by providing reducing power for protection against oxidative stress and for mitochondrial fatty acid synthesis (mtFAS), proline biosynthesis, lysine degradation, and the beta oxidation of polyunsaturated fatty acids. NADK2 was identified in humans by Ohashi et al. in 2012, more than a decade after its cytosolic counterpart, NADK1. Mutations in the NADK2 gene cause an autosomal recessive disorder known as NADK2 deficiency.
Somalia was likely one of the first lands to be settled by early humans due to its location. Hunter-gatherers who would later migrate out of Africa likely settled here before their migrations. During the Stone Age, the Doian and Hargeisan cultures flourished here. The oldest evidence of burial customs in the Horn of Africa comes from cemeteries in Somalia dating back to the 4th millennium BC. The stone implements from the Jalelo site in the north were also characterised in 1909 as important artefacts demonstrating the archaeological universality during the Paleolithic between the East and the West. According to linguists, the first Afroasiatic-speaking populations arrived in the region during the ensuing Neolithic period from the family's proposed urheimat ("original homeland") in the Nile Valley, or the Near East. The Laas Geel complex on the outskirts of Hargeisa in northwestern Somalia dates back approximately 5,000 years, and has rock art depicting both wild animals and decorated cows. Other cave paintings are found in the northern Dhambalin region, which feature one of the earliest known depictions of a hunter on horseback. The rock art is dated to 1,000 to 3,000 BC. Additionally, between the towns of Las Khorey and El Ayo in northern Somalia lies Karinhegane, the site of numerous cave paintings, which collectively have been estimated to be around 2,500 years old. The camel is believed to have been domesticated in the Horn region between the 2nd and 3rd millennium BC. From there, it spread to Egypt and the Maghreb.
Louisville hotspot (23) 53°36′S 140°36′W, w= 1 az= 316° ±5° rate= 67 ±5 mm/yr Possibly related to the Ontong Java Plateau (125–120 Ma). Foundation hotspot/Ngatemato seamounts (57) 37°42′S 111°06′W, w= 1 az= 292° ±3° rate= 80 ±6 mm/yr Macdonald hotspot (24) 29°00′S 140°18′W, w= 1 az= 289° ±6° rate= 105 ±10 mm/yr North Austral/President Thiers (President Thiers Bank, 58) 25°36′S 143°18′W, w= (1.0) az= 293° ± 3° rate= 75 ±15 mm/yr Arago hotspot (Arago Seamount, 59) 23°24′S 150°42′W, w= 1 az= 296° ±4° rate= 120 ±20 mm/yr Maria/Southern Cook hotspot (Îles Maria, 60) 20°12′S 153°48′W, w= 0.8 az= 300° ±4° Samoa hotspot (35) 14°30′S 168°12′W, w= 0.8 az= 285°±5° rate= 95 ±20 mm/yr Crough hotspot (Crough Seamount, 61) 26°54′S 114°36′W, w= 0.8 az= 284° ± 2° Pitcairn hotspot (31) 25°24′S 129°18′W, w= 1 az= 293° ±3° rate= 90 ±15 mm/yr Society/Tahiti hotspot (38) 18°12′S 148°24′W, w= 0.8 az= 295°±5° rate= 109 ±10 mm/yr Marquesas hotspot (26) 10°30′S 139°00′W, w= 0.5 az= 319° ±8° rate= 93 ±7 mm/yr Caroline hotspot (4) 4°48′N 164°24′E, w= 1 az= 289° ±4° rate= 135 ±20 mm/yr Hawaii hotspot (12) 19°00′N 155°12′W, w= 1 az= 304° ±3° rate= 92 ±3 mm/yr Socorro/Revillagigedos hotspot (37) 19°00′N 111°00′W Guadalupe hotspot (11) 27°42′N 114°30′W, w= 0.8 az= 292° ±5° rate= 80 ±10 mm/yr Cobb hotspot (5) 46°00′N 130°06′W, w= 1 az= 321° ±5° rate= 43 ±3 mm/yr Bowie/Pratt-Welker hotspot (3) 53°00′N 134°48′W, w= 0.8 az= 306° ±4° rate= 40 ±20 mm/yr
Sources: en.wikipedia.org
==== Integrate-and-Fire Model ==== The integrate-and-fire model aims for mathematic simplicity in describing biological systems by focusing on, and only on, the threshold activity of a neuron. By doing so, the model successfully reduces the complexity of a complicated system; however it ignores the actual mechanisms of action and replaces them with functions that define how the output of a system depends on its input. This model has been used to describe the release of hormones to the posterior pituitary gland, specifically oxytocin and vasopressin.
==== Hormones ==== BST is destroyed in the digestive system and even if directly injected, has not been found to have any direct effect on humans. Researchers have found that "IGF-1 in milk is not denatured by pasteurization and the extent to which intact, active IGF-1 is absorbed through the human digestive tract remains still however uncertain" implicating that an extensive study on the nature of IGF-1 in relation to rBST milk is required. FDA rBST labeling guidelines state, "FDA is concerned that the term 'rBST free' may imply a compositional difference between milk from treated and untreated cows rather than a difference in the way the milk is produced. Without proper context, such statements could be misleading. Such unqualified statements may imply that milk from untreated cows is safer or of higher quality than milk from treated cows. Such an implication would be false and misleading". The FDA has determined that no significant difference has been shown between milk derived from rBST treated and non-rBST treated cows. The FDA, World Health Organization, and National Institutes of Health have independently stated that dairy products and meat from rBST-treated cows are safe for human consumption. The American Cancer Society issued a report declaring, "The evidence for potential harm to humans [from rBGH milk] is inconclusive. It is not clear that drinking milk produced using rBGH significantly increases IGF-1 levels in humans or adds to the risk of developing cancer. More research is needed to help better address these concerns."
Committee on Natural Resources Subcommittee on Federal Lands Subcommittee on Water, Wildlife and Fisheries Committee on Oversight and Government Reform Subcommittee on Delivering on Government Efficiency (Ranking Member)
While certain effects of developmental temperature, like body size, are irreversible in ectotherms, others can be reversible. When Drosophila melanogaster develop at cold temperatures they will have greater cold tolerance, but if cold-reared flies are maintained at warmer temperatures their cold tolerance decreases and heat tolerance increases over time. Because insects typically only mate in a specific range of temperatures, their cold/heat tolerance is an important trait in maximizing reproductive output. While the traits described above are expected to manifest similarly across sexes, developmental temperature can also produce sex-specific effects in D. melanogaster adults.
Acetamide (systematic name: ethanamide) is an organic compound with the formula CH3CONH2. It is an amide derived from ammonia and acetic acid. It finds some use as a plasticizer and as an industrial solvent. The related compound N,N-dimethylacetamide (DMA) is more widely used, but it is not prepared from acetamide. Acetamide can be considered an intermediate between acetone, which has two methyl (CH3) groups either side of the carbonyl (CO), and urea which has two amide (NH2) groups in those locations. Acetamide is also a naturally occurring mineral with the IMA symbol: Ace.
Sources: en.wikipedia.org
It targets PPARδ, a nuclear receptor involved in lipid and energy metabolism. It does not act primarily on androgen receptors. This distinction separates it from SARMs.
Rodent studies found dose-dependent tumors in several organs. The sponsor discontinued the program over cancer concerns. Human risk from long-term use remains unknown.
Controlled human endurance trials are lacking. Animal studies show increased exercise capacity under some conditions. Anecdotal reports are not equivalent to clinical evidence.
Cardarine targets PPARδ, a nuclear receptor involved in lipid and energy metabolism. It does not bind the androgen receptor in the way SARMs do.