GW 501516

GW-501516 (Cardarine) 20mg by Dragon Pharma

GW-501516, commonly known as Cardarine, is Dragon Pharma's formulation at 20mg per tablet — a PPARδ (peroxisome proliferator-activated receptor delta) agonist that enhances fatty acid oxidation, endurance capacity and lipid metabolism. Supplied in a 100-tablet pack, GW-501516 is frequently and incorrectly classified as a SARM — it is not. Its mechanism is entirely different from androgen receptor modulators, and understanding this distinction is essential to understanding both its effects and its safety profile.

Also searched as: GW 501516, Cardarine 20mg, PPAR delta agonist, GW501516 Dragon Pharma.

GW-501516 Is Not a SARM — The Critical Misclassification

This is the most pervasive and consequential error in competitor content on this compound:

• SARMs (Selective Androgen Receptor Modulators) bind androgen receptors — the same receptors as testosterone and other anabolic steroids — with tissue-selective activity
• GW-501516 does not bind androgen receptors. It binds PPARδ (peroxisome proliferator-activated receptor delta) — a nuclear receptor that regulates fatty acid oxidation gene expression, mitochondrial biogenesis and metabolic switching
• GW-501516 has no anabolic activity, produces no testosterone suppression, does not require PCT, and does not produce any of the hormonal effects of SARMs or AAS
• Its mechanism — activating PPARδ to shift energy metabolism toward fat oxidation — is pharmacologically similar to the pathway activated by endurance exercise at the cellular level
• It is classified alongside SARMs in some contexts purely because it is commonly used by the same community and sold through the same channels — not because of any shared mechanism

The PPARδ Mechanism — How GW-501516 Actually Works

PPARδ is a nuclear receptor involved in regulating genes governing fatty acid oxidation and mitochondrial function. GW-501516's activation of PPARδ produces several downstream effects:

• Fatty acid oxidation upregulation: PPARδ activation increases expression of genes encoding enzymes involved in beta-oxidation — the cellular process of burning fatty acids for energy. The shift toward fat as a primary fuel source is similar to the metabolic adaptation seen in endurance-trained athletes
• Mitochondrial biogenesis: PPARδ activates PGC-1α co-activation — the same pathway stimulated by aerobic exercise — increasing mitochondrial density in skeletal muscle. More mitochondria per fibre = greater capacity for sustained aerobic energy production
• Muscle fibre type shift: Animal studies demonstrated a shift toward type I (slow-twitch, oxidative) muscle fibres with PPARδ activation — physically altering muscle composition toward endurance performance
• Endurance without training: The 2008 Narkar et al. study in Cell demonstrated that GW-501516 increased running endurance by 68% in untrained mice — generating significant media attention as a potential "exercise pill"

The Safety Question — Why GSK Discontinued Development

This is the most important safety information that competitor content almost universally omits or minimises:

• GlaxoSmithKline (GSK) developed GW-501516 in the 1990s-2000s for metabolic syndrome and dyslipidaemia indications
• In 2007, GSK halted all development of GW-501516 after animal toxicology studies showed rapid and widespread tumour development across multiple organ systems — in all animal species tested and at multiple dose levels
• The mechanism of concern: PPARδ activation may promote tumour proliferation and progression in pre-existing cancer cells. PPARδ plays a role in cell proliferation pathways, and its activation was found to accelerate cancer progression in models with pre-existing cancer
• Key distinction: GW-501516 does not appear to initiate cancer in healthy cells in all studies — the primary concern is its potential to accelerate existing tumour growth
• Human clinical data is very limited — the compound never progressed to Phase III trials. The safety picture in humans at the doses used in performance contexts is not established by rigorous clinical evidence
• WADA added GW-501516 to its prohibited list in 2009 specifically citing the cancer risk findings as a reason beyond doping concerns

Effects and Benefits

• Significant endurance enhancement — documented 68% increase in untrained mouse endurance; human reports consistent with meaningful aerobic capacity improvement
• Enhanced fatty acid oxidation — metabolic shift toward fat as primary fuel, improving body composition during caloric deficits
• Improved lipid profile — PPARδ activation associated with reduced LDL and triglycerides, increased HDL in animal studies
• No hormonal effects — no testosterone suppression, no estrogen effects, no PCT required
• Anti-catabolic during caloric deficit — fat oxidation shift preserves muscle glycogen, reducing catabolism of lean tissue

Dosage and Administration

With a ~16-24 hour half-life, once-daily dosing maintains stable blood levels. The 20mg tablet represents the higher end of commonly used doses — some users start at 10mg (half tablet) before escalating. GW-501516 does not require PCT and can be discontinued without a taper. It does not interact with androgen receptors or the HPG axis and can be used during AAS cycles or independently.