GW-501516 (Cardarine Peptide Context)
Synthetic small-molecule PPAR-delta agonist, not a peptide; researched for endurance metabolism and discontinued over rodent tumor findings.
Overview
Despite the Peptide Context label used in some catalogs, GW-501516 (often called Cardarine in sports circles) is a synthetic small-molecule agonist of the peroxisome proliferator-activated receptor delta (PPAR-delta), not a peptide. It was developed in the 1990s by GlaxoSmithKline and Ligand Pharmaceuticals as a candidate for metabolic disease, where it was shown to shift muscle toward fat-oxidative fiber types and increase exercise endurance in rodents. Clinical development was stopped after dose-dependent tumors appeared in long-term rodent studies.
Mechanism
GW-501516 binds and activates PPAR-delta, a nuclear receptor that regulates genes for fatty-acid oxidation, mitochondrial biogenesis, and slow-twitch fiber programming. Activation increases lipid utilization and is associated with endurance-like metabolic adaptations in animal studies.
Dosing
In published animal research the compound is given orally at milligram-per-kilogram doses specified per protocol. There is no approved human dose, and the rodent carcinogenicity findings argue against any human use rationale.
Expected Effects
- increased running endurance and fatty-acid oxidation in rodent studies
- shifts toward oxidative muscle fiber types in animal models
- favorable effects on lipids reported in early human trials
Side Effects & Tolerability
The decisive tolerability issue is the tumor signal: long-term rodent studies found dose-dependent cancers in multiple tissues, which ended pharmaceutical development. This finding is a documented, published reason the compound is not clinically available.
Storage
Research-grade material should be stored per the supplier label, typically cool and dry and protected from light; it is an oral small molecule rather than a reconstituted peptide.