β-Hydroxybutyrate enhances chondrocyte mitophagy and reduces cartilage degeneration in osteoarthritis via the HCAR2/AMPK/PINK1/Parkin pathway (Zhuang et al., 2024), and it alleviates cartilage senescence through the hnRNP A1-mediated upregulation of PTEN (Xia et al., 2023). Here, HCAR2 is linked to osteoarthritis.