Lipid droplets (LDs) are dynamic organelles found in nearly all cells, characterized by a hydrophobic core of neutral lipids surrounded by a monolayer of phospholipids. They serve as storage sites for lipids, energy, and membrane components, and are involved in various cellular functions, including viral replication, protein storage, and lipid metabolism. LDs are implicated in numerous physiological and pathological conditions, such as obesity and metabolic diseases. Recent advances in LD research have revealed their complex biology, including their role in lipid synthesis, storage, and metabolism. LDs are found in most cells, with variations in size and number depending on the cell type and physiological state. They are composed of neutral lipids such as triacylglycerols (TGs) and sterol esters (SEs), and are associated with various proteins that regulate their formation, growth, and function. LDs can grow by expansion or coalescence, and their surface is coated with polar lipids and proteins that help in their stabilization. LDs are also involved in lipid droplet formation and catabolism, and their proteins can be targeted to LDs through various mechanisms, including direct binding, lipid anchors, and interactions with other LD-bound proteins. LDs interact with other organelles such as the ER, mitochondria, and peroxisomes, and their movement within cells can be coordinated and microtubule-dependent. Lipids in LDs can be mobilized by lipases, and their catabolism can occur through lipolysis or autophagy. LDs play a significant role in physiology and disease, with their dysfunction contributing to various conditions such as obesity, diabetes, and liver disease. Understanding LD biology is crucial for elucidating the mechanisms of lipid metabolism and its regulation in health and disease.Lipid droplets (LDs) are dynamic organelles found in nearly all cells, characterized by a hydrophobic core of neutral lipids surrounded by a monolayer of phospholipids. They serve as storage sites for lipids, energy, and membrane components, and are involved in various cellular functions, including viral replication, protein storage, and lipid metabolism. LDs are implicated in numerous physiological and pathological conditions, such as obesity and metabolic diseases. Recent advances in LD research have revealed their complex biology, including their role in lipid synthesis, storage, and metabolism. LDs are found in most cells, with variations in size and number depending on the cell type and physiological state. They are composed of neutral lipids such as triacylglycerols (TGs) and sterol esters (SEs), and are associated with various proteins that regulate their formation, growth, and function. LDs can grow by expansion or coalescence, and their surface is coated with polar lipids and proteins that help in their stabilization. LDs are also involved in lipid droplet formation and catabolism, and their proteins can be targeted to LDs through various mechanisms, including direct binding, lipid anchors, and interactions with other LD-bound proteins. LDs interact with other organelles such as the ER, mitochondria, and peroxisomes, and their movement within cells can be coordinated and microtubule-dependent. Lipids in LDs can be mobilized by lipases, and their catabolism can occur through lipolysis or autophagy. LDs play a significant role in physiology and disease, with their dysfunction contributing to various conditions such as obesity, diabetes, and liver disease. Understanding LD biology is crucial for elucidating the mechanisms of lipid metabolism and its regulation in health and disease.