Laminarin is a polysaccharide primarily found in brown algae, such as those from the genus Laminaria, where it serves as a storage carbohydrate. Chemically, it is a β-glucan composed mainly of β-(1→3)-D-glucose linkages with occasional β-(1→6) branches, making it a linear polymer that is highly water-soluble. This structure contributes to its biological roles, including acting as a prebiotic in the human gut by promoting beneficial microbiota, and exhibiting immunomodulatory and antioxidant properties. In food and nutrition, laminarin is valued for its potential health benefits, such as lowering cholesterol levels and supporting immune function, leading to its use in dietary supplements and functional foods. From a scientific perspective, research indicates that laminarin can be extracted via hot water methods and has been studied for applications in pharmaceuticals and cosmetics due to its biocompatibility. Its molecular weight typically ranges from 2,000 to 10,000 g/mol, influencing its viscosity and solubility. Overall, laminarin represents a natural compound with promising bioactive properties, supported by peer-reviewed studies in journals like those from the American Chemical Society and Marine Drugs, highlighting its safety and efficacy in various contexts.