Aims: Platelet-rich plasma (PRP) contains diverse bioactive factors, but its potential role in central regulation of energy balance remains unexplored. This study investigated whether central PRP administration alters metabolic homeostasis in diet-induced obese (DIO) mice and examined associated hypothalamic responses under obese and inflammatory conditions. Materials and Methods: PRP was administered intracerebroventricularly in mouse models of DIO and lipopolysaccharide (LPS)-induced systemic inflammation. Body weight, food intake, energy metabolism, and adiposity were assessed alongside hypothalamic microglial morphology and transcriptomic profiling. Results: A single intracerebroventricular PRP injection reduced body weight in DIO mice, with the effect persisting throughout the 7-day observation period. PRP also decreased cumulative food intake, relative gonadal white adipose tissue weight, and fasting glucose, accompanied by increased energy expenditure, oxygen consumption, fat utilization, and physical activity. In both DIO and LPS-treated mice, PRP reduced IBA1-positive area per microglial cell in the arcuate nucleus without altering microglial number. Hypothalamic RNA sequencing revealed changes in immune and metabolic signaling, extracellular matrix organization, and growth-related pathways, suggesting a complex transcriptional response rather than uniform suppression of inflammation. Conclusions: A single central PRP administration induces sustained weight loss and favorable metabolic changes in DIO mice, accompanied by region-specific hypothalamic microglial and transcriptional responses. These findings identify central PRP as a potential modulator of energy balance and provide a basis for investigating its active components and underlying mechanisms.