Nanostructured lipid carriers (NLCs) represent a novel nanoparticulate drug delivery system composed of solid lipids, liquid lipids, emulsifying agents, and an aqueous phase. In recent years, NLCs have garnered considerable scientific and clinical interest due to their superior drug delivery capabilities, offering notable advantages over conventional dosage forms. Nanostructured lipid carriers (NLCs) are second generation lipid-based nanocarriers formulated using biocompatible solid lipids, liquid lipids, surfactants, and co-surfactants. These systems are capable of encapsulating a wide range of pharmacological agents, offering controlled drug release, improved drug stability and scalability for industrial production without the requirement for organic solvents. This article provides a comprehensive overview of nanostructured lipid carriers (NLCs), focusing on their structural composition, preparation techniques, characterization methods, and the advantages they offer over first-generation lipid-based nanoparticles.