N-terminally acetylated Leu-enkephalin is primarily used in research settings to study opioid receptors and their signaling pathways. It serves as a modified peptide analog to investigate the effects of acetylation on receptor binding affinity and activity. This compound is particularly valuable in neuroscience and pharmacology for understanding pain modulation, addiction mechanisms, and the role of enkephalins in the central nervous system. Additionally, it is utilized in biochemical assays to explore peptide stability, metabolism, and interactions with enzymes such as peptidases. Its application extends to drug development, where it aids in designing peptide-based therapeutics with enhanced pharmacokinetic properties.