Glutathione vs GW-0742

Immune

Metabolic

Research Only

Research Only

Glutathione cycles between reduced (GSH) and oxidized (GSSG) forms, donating electrons to reactive oxygen species via glutathione peroxidase. It serves as a cofactor for glutathione S-transferases (GSTs) in Phase II detoxification, maintains reduced protein thiols, supports T-cell proliferation and NK cell cytotoxicity, and regenerates vitamins C and E. Proposed skin-lightening activity is attributed to inhibition of tyrosinase and a shift from eumelanin toward phaeomelanin synthesis, though clinical evidence is limited and largely from small Asian dermatology trials.

GW-0742 is a high-affinity, highly selective agonist of human PPARδ (EC50 = 1.1 nM for hPPARδ transactivation vs ~1.1 µM for hPPARα and ~2 µM for hPPARγ), conferring ~1000-fold selectivity for PPARδ over the other PPAR subtypes. Upon activation, PPARδ heterodimerizes with RXR and binds PPAR-response elements (PPREs) to alter transcription of genes governing fatty-acid oxidation, glucose utilization, and inflammatory signaling. In mice, however, GW-0742-induced hepatomegaly, hepatic/skeletal-muscle peroxisome proliferation, and skeletal myopathy were shown to be predominantly mediated by off-target PPARα cross-activation rather than PPARδ—a mechanism-based toxicity concern at animal-study exposures.