ULK-101 is primarily used in biochemical and pharmaceutical research as a potent and selective inhibitor of the ULK1 (Unc-51 like autophagy activating kinase 1) enzyme, which plays a critical role in the initiation of autophagy—a cellular degradation and recycling process. By targeting ULK1, ULK-101 allows researchers to modulate autophagy in cell-based studies, making it a valuable tool for investigating the role of autophagy in diseases such as cancer, neurodegenerative disorders, and infectious diseases. In cancer research, ULK-101 is used to explore how inhibition of autophagy affects tumor cell survival, particularly in combination with other anticancer therapies. Since some cancer cells rely on autophagy to survive under stress, blocking this pathway with ULK-101 can enhance the efficacy of chemotherapy or radiation. It is also employed in studies examining metabolic regulation and cellular responses to nutrient deprivation. Due to its selectivity and cell permeability, ULK-101 is favored in mechanistic studies over less specific autophagy inhibitors. It is commonly applied in in vitro models to dissect signaling pathways involving ULK1 and to validate ULK1 as a therapeutic target. While still primarily a research compound, its application supports the development of future drugs targeting autophagy-related pathways.