Cardarine (GW-501516) monograph

Cardarine (GW-501516)

Overview

Cardarine (GW-501516) is an investigational selective PPAR-δ agonist studied mainly for dyslipidemia and other metabolic indications, not an approved medicine. It became popular in bodybuilding circles because of its reputation for improving endurance and fat metabolism, but human evidence is limited and safety concerns are significant. It is prohibited in sport and is associated with carcinogenicity concerns in preclinical data.

Pharmacokinetics & Mechanism

• Class: Selective PPAR-δ (PPARβ/δ) agonist; investigational metabolic modulator
• Mechanism of action: Activates PPAR-δ, a nuclear receptor that regulates transcription of genes involved in fatty acid oxidation, lipid metabolism, and energy homeostasis. In skeletal muscle and adipose tissue, PPAR-δ activation shifts substrate use toward fat oxidation and away from glucose, which is the biologic basis for the claimed endurance effects. Human performance-enhancement effects are not well established.
• Target(s): Primary target: peroxisome proliferator-activated receptor delta (PPARβ/δ; gene PPARD). Downstream pathways include fatty-acid oxidation and metabolic-gene transcription programs; AMPK-related metabolic effects are discussed in some literature but are not the primary direct target.
• Route(s) of administration: Oral only in the clinical/investigational setting. No approved injectable, transdermal, or other route exists; community use is typically oral liquid or capsules from research-chemical vendors.
• Onset: Not well established in humans. Metabolic gene-expression effects are expected over days rather than minutes to hours; performance effects, if any, would likely require repeated dosing.
• Half-life: About 16–24 hours in human studies and reviews, so once-daily dosing is commonly assumed. Some secondary sources and community writeups cite roughly 20–24 hours; exact human half-life is not robustly established and should be treated as approximate.
• Metabolism / clearance: Not well established from accessible authoritative sources in humans. Published summaries describe it as a small-molecule investigational compound with hepatic metabolism and systemic clearance; detailed human metabolic pathways are not clearly established in the sources reviewed.