What is Cardarine (GW501516)? – Changing The Course Of Boxing History

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Cardarine – The Mystery Banned Substance

The boxing universe was shocked as it received news that the heavyweight clash between two top class heavyweight fighters, Jarrell Miller vs. Anthony Joshua had been called off. But what happened? Earliest reports said he failed voluntary drugs tests by testing positive for Endurobol, also known as GW501516 or Cardarine. This begs the question, What is Cardarine? And why would a high-profile professional use it? We dive deeper into the history of this substance and its miracle performance enhancing abilities.

How GW501516 Changed Boxing History

Jarrell Miller popularly known as “Big Baby” was to fight Anthony Joshua on June 1st 2019. However, he failed a second drug test on March 20 which made his boxing license reversed in the City of New York. Earliest reports said he failed two voluntary drug tests, as he tested positive for substance use. He initially tested positive for a sporting banned substance—GW501516, and a second conducted test revealed he had traces of human growth hormone (HGH). This ultimately lead to Jarrel Miller being disqualified and Joshua without an opponent. Step forward Andy Ruiz, a  cherry-picked Mexican challenger. Team Joshua planned for this to be a walk in the park but it was entirely the opposite. Andy Ruiz, the 11-1 underdog, handed a devastating defeat to Joshua winning the fight in the 7th round by TKO. This made Andy Ruiz the first Mexican Heavyweight in boxing history.

Andy Ruiz Stands Over Anthony Joshua After Knockdown

What is Cardarine?

Cardarine also referred to as GW501516, was developed in the ’90s and 2000s by Ligand Pharmaceuticals and GlaxoSmithKline—both are pharmaceutical companies. Contrary to popular belief,  it is not a SARM but a Peroxisome proliferator-activated receptor (PPAR) Agonist.  The initial aim for the two companies was to develop a drug to treat dyslipidemia (Pelton, 2016). Subsequent trials discovered that Cardarine helped to manage type 2 diabetes and obesity.

During the onset of years 2000’s, word about Gw501516 and its miracle properties began to spread like wildfire. Many expressed their concerns about the use of substance at the 2008 Beijing Olympics. They feared that athletes could be using the performance enhancing supplement for endurance gains in sporting challenges. Furthermore, no methods existed to detect the substance as regulations did not control it. As a result of these concerns, one of the main researchers developed a urine test and presented it to the International Olympic Committee. The World Anti-Doping Agency (WADA) added Endurobol to the prohibited list in 2009 penalizing athletes who use the substance for performance gains.

Cardarine GW501516 Infographic by Phlex Labs


How Does Cardarine Work?

PPAR’s are a class of nuclear transcription factors which help to maintain metabolism (Tyagi et al., 2011). Recent research has found that in particular, PPAR-delta helps to regulate skeletal reprogramming, wound healing and mitochondrial respiration. GW501516 is a PPAR-delta agonist meaning it binds to this receptor and in turn, upregulates the expression of genes associated with contractile proteins, mitochondrial biogenesis, and lipid oxidation. Over-expression of PPAR-delta is usually a result of exercise.

Why use Cardarine?

There are two main reasons as to why athletes take Cardarine:

  • Endurance / Stamina Gains
  • Fat Loss

Cardarine Endurance Gains

Endurance is a key attribute in modern sports. It is evermore important that an athlete can withstand fatigue and remain active for long periods of time. In the case of Jarrel Miller, boxers need immense endurance so they can withstand 12-rounds of boxing. However, building endurance can take years and is a gruelling process. Consequently, athletes look towards supplements to give them the edge thus making products such as Cardarine very enticing. PPAR-delta helps to reprogram muscle fibres and increase skeletal muscle metabolism. As a result, GW501516 helps users experience a revamped endurance significantly reducing fatigue. A 2015 study showed that Endurobol was able to increase running endurance by 68.6% in untrained subjects when compared to a control group (Chen et al.,).

Bar Chart Of Bar Chart of Running Distance, Blood Glucose and Lactate of 4 groups in a Cardarine Study.
Bar Chart of Running Distance, Blood Glucose and Lactate of 4 groups (Chen et al., 2015). NN = Untrained and not supplemented NG = Untrained and supplemented with GW501516 TN = Trained but not supplemented  TG = Trained and supplemented with GW501516

Cardarine Fat Burning and Weight Loss

In the world of heavyweight boxing, having weight is a doubled-edged sword. On one hand, it can help boxers generate more force behind their punches which can lead to knockouts. On the other hand, it can seriously slow them down. When compared to Anthony Joshua, Big Baby Miller was considerably out of shape. By using Cardarine, Miller could cut down considerable fat mass improving his overall physique and athleticism. Gw501516 provides an equal benefit to both female and males with regards to fat burning. The PPAR-delta activation caused by Cardarine drives metabolism towards fatty acids as the preferred energy source. A 2008 study showed a significant reduction in fasting plasma triglycerides (-30%), LDL cholesterol (-23%) and liver fat content (-20%) in six healthy moderately overweight subjects (Risérus et al.,)This effect was linked to the increased fat oxidation caused by GW501516.

Other Uses of Cardarine

Blood Vessels and Heart Health

Apart from helping to reduce cholesterol, GW501516 can a direct impact on blood vessels and heart health. In a 2012 study by Santhanam et al., Cardarine prevented uncoupling of endothelial nitric oxide synthase (eNOS) and increased total nitrate content in cerebral microvessels. Endothelial NOS plays a protective role in the cardiovascular system. Its main role is in the regulation of vascular tone i.e. diameter of a blood vessel when fully dilated. Too much resistance against the artery wall is called hypertension or high blood pressure. This causes the heart to work harder to move blood around the body and can ultimately result in a stroke or heart attack.  Having a healthy cardiovascular system is beneficial for anyone but the effects of good blood circulation are more pronounced for athletes.

Wound Healing and Anti-Inflammatory

In sports such as boxing, recovery is an important factor. After countless rounds of sparring and training, damage to the body is unavoidable. There are methods to reduce inflammation such as taking ice baths but they are not for everyone. Generally, trials have shown Cardarine to suppress inflammation by antagonising multiple pro-inflammatory pathways. Additionally, when applied to the skin, Endurobol showed accelerated healing of diabetic wounds via redox modulation of wound microenvironment (Wang et al., 2015). This effect is ideal for boxers as they are prone to inflammation after fights.

Side Effects of Cardarine

  • Cardarine is not safe to use during pregnancy as it poses risk to fetal development
  • Induces wakefulness therefore not suitable for individuals who have trouble sleeping

Does Cardarine Cause Cancer? – A Misconception

Infographic on Cardarine Gw501516 and Cancer

GlaxoSmithKline Trials

There is a lot of conflicting information regarding the link between Cardarine and cancer. The connection arises from two carcinogenicity studies conducted by GlaxoSmithKline in 2009. In the first study conducted by Geiger et al., male Han Wistar rats were administered 0, 5, 15 or 30 mg/kg/day for the first 6 weeks and then either 0, 5, 15 or 40 mg/kg/day for the remainder of the study. Female rats were given 0, 3, 10 or 20 mg/kg/day for the entire study. Neoplasms did form in all areas of the body for both genders.
Likewise, the second study lasted a duration of 104 weeks but the test subjects were CD1 mice with dosages of 0, 10, 30, 60 or 80 mg/kg/day (Newsholme et al., 2009). This trial also resulted in neoplasms forming with survival rates decreasing at dosages > 30 mg/kg/day.

Inconsistencies In The Trial

A number of discrepancies arise when scrutinising these trials. Firstly, neither of the studies have been published as full peer-reviewed papers (Mitchell & Bishop-Bailey, 2019). As a result, other academics could not evaluate the findings from these trials. Secondly, the subjects were dosed daily with 5-6 times the recommended dosage for nearly two-thirds of their lifespan as Han Wistar & CD1 mice have a lifespan of approximately 3 years (Ades, 2015). It is confusing as to why GSK would expose the subjects to this sort of dosage. Common knowledge tells us too much of anything can have repercussions.

Evidence To The Contrary –  Does Cardarine Inhibit Cancer?

Conversely, there are a number of studies which reveal the exact opposite. In the same journal, Toxicology 2009, a study conducted by Coleman & Heuvel showed GW501516 to inhibit the proliferation of human pancreatic cancer cells. Another study examined the effects of PPAR-beta & delta ligands (GW501516 & GW0742) on human cell lines. Neither ligand resulted in an increase in cell growth or phosphorylation of Akt. Also, results showed no increase in the expression of VEGF or COX2 in any cancer cell line (Hollingshead et al., 2007). A 2008 study by Girror et al., showed that the PPAR-delta ligand, GW501516, actually inhibited growth of UACC903 (melanoma) and MCF7 (breast cancer). In addition, He et al., conducted a study in 2008 on human lung cancer cell lines. The results from the study showed that ligand activation did not exhibit significant modulation of cell proliferation in these cell lines.

Effective Cardarine Dosage

Dosages for Cardarine have varied in clinical trials. In a 2004 study by GSK, subjects were administered a daily dosage of 2.5-10 mg. In another 2004 study by GSK, a 10mg dosage was used to evaluate the effectiveness of GW501516 on body fat and inflammation. Based on the animal and human trials, a dosage from 2.5mg – 20mg is adequate enough to see results.

Where to Buy Cardarine

Many online vendors claim to sell Cardarine but the majority do not have HPLC testing or COA’s for any of their products. Poor quality products can give undesired results during testing and can be detrimental to your wallet. Phlex Labs is a stockist of high purity Cardarine (GW501516), SARMs and other research chemicals. Phlex Lab specialists can also help with any further questions on Cardarine and how it can be used for testing and research purposes. You can purchase Endurobol by clicking here or on the image below.

Phlex Labs Cardarine GW501516

Final Words

Cardarine’s performance enhancing abilities are very evident. Clinical trials and studies have shown GW501516 to increase fat loss through improving mitochondrial metabolism and endurance through reprogramming muscle fibres. Additional benefits have been reported such as wound healing and improved blood flow. The multiple strengths of Cardarine have made it an attractive substance for athletes looking to gain an edge over their opponents. Jarrel Miller is only one example of an athlete who has looked to Endurobol to improve his endurance and burn fat. Although available from numerous sellers, Cardarine should be purchased from reputable suppliers to ensure high quality.


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