PPARGC1B (Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-Beta) is a transcriptional coactivator that plays a key role in the regulation of cellular energy metabolism, particularly in tissues with high metabolic demands such as the heart, skeletal muscle, liver, and brain. Encoded by the PPARGC1B gene in humans, it interacts with a variety of nuclear receptors and transcription factors, including PPARs, ERRs, and NRF1, to promote the expression of genes involved in mitochondrial biogenesis, oxidative phosphorylation, fatty acid oxidation, and glucose homeostasis. Unlike its close paralog PGC-1α, PGC-1β is less responsive to physiological stimuli like cold exposure or exercise but is more constitutively expressed and tightly linked to lipid metabolism and reactive oxygen species (ROS) detoxification.