GW-501516

GW-501516 (Cardarine) — Research Overview

GW-501516 is a synthetic PPARδ (peroxisome proliferator-activated receptor delta) agonist, also designated GW1516 or GSK-516. It was originally developed by GlaxoSmithKline and Ligand Pharmaceuticals as part of a metabolic disease research program. Although frequently grouped with SARMs in performance research discussions, GW-501516 operates through an entirely different receptor mechanism — PPARδ rather than the androgen receptor.

Mechanism of Action

PPARδ (also called PPARβ/δ) is a ligand-activated nuclear receptor that regulates gene expression involved in fatty acid oxidation, glucose utilization, and mitochondrial function. Upon GW-501516 binding, PPARδ heterodimerizes with RXR (retinoid X receptor) and binds PPAR response elements (PPREs) in target gene promoters. This activates transcription of:

• CPT1 (carnitine palmitoyltransferase 1) — rate-limiting enzyme in mitochondrial fatty acid transport
• PDK4 (pyruvate dehydrogenase kinase 4) — shifts substrate preference from glucose to fatty acids
• ABCA1 (ATP-binding cassette transporter A1) — increases reverse cholesterol transport
• UCP3 (uncoupling protein 3) — thermogenic uncoupling in skeletal muscle mitochondria

Research Applications

GW-501516 has been studied extensively in preclinical models across several fields:

• Metabolic syndrome research: Insulin sensitivity, dyslipidemia, and fatty acid oxidation in obesity models
• Endurance physiology: Mitochondrial biogenesis and fiber-type switching in skeletal muscle — landmark mouse studies showed significant increases in running endurance without training
• Cardiovascular research: HDL cholesterol elevation, reverse cholesterol transport, and atherosclerosis models
• Muscle fiber composition: Fast-to-slow (Type IIb → Type I) fiber-type transition studies
• NASH/NAFLD models: Hepatic lipid accumulation and inflammatory marker studies
• PPARδ receptor pharmacology: Selectivity studies vs. PPARα and PPARγ agonists

Important Research Context

GW-501516’s clinical development was discontinued after preclinical carcinogenicity studies revealed dose-dependent tumor formation in multiple organ systems in rodent models. This discontinuation makes it a compound of significant pharmacological interest — researchers study both the carcinogenic mechanisms (rapid proliferation of pre-neoplastic cells, PPARδ-mediated anti-apoptotic signaling) and the metabolic benefits observed at sub-carcinogenic exposures. Research use requires appropriate institutional safety review.

Pharmacokinetic Profile

GW-501516 is orally bioavailable with high protein binding (>99.9%). It undergoes extensive oxidative metabolism via CYP3A4, producing sulfoxide and hydroxylated metabolites. Half-life is approximately 16–24 hours in preclinical models. It distributes widely into tissues including fat, liver, and skeletal muscle — consistent with its role as a PPARδ agonist targeting lipid-metabolizing tissues.

Supplied For

Research and laboratory use by qualified investigators under appropriate institutional safety and ethical oversight. Not for human consumption. Certificate of Analysis available upon request.