Beta Glucans: The 21st Century's Multifunctional Key to Drug Delivery

β-Glucans are naturally occurring polysaccharides composed of β-D-glucose units, increasingly recognized for their multifunctional roles in human health and industrial biotechnology. Their physicochemical parameters, including molecular weight, branching, solubility, and viscosity, critically determine biological activity, rendering them superior to α-glucans in nutraceutical, pharmaceutical, and cosmeceutical applications. The motivation for this review arises from the need to integrate fragmented knowledge into a unified framework that connects structural attributes with therapeutic and industrial outcomes. This review consolidates evidence from biochemical, biophysical, and molecular studies, emphasizing β-glucan interactions with immune receptors, including Complement Receptor 3, Lactosylceramide, Scavenger Receptors, and Dectin-1, which mediate antifungal defense, immune regulation, and the control of inflammation. The scope further extends to their expanding applications in the food, beverage, healthcare, cosmetics, animal feed, agriculture, vaccine adjuvant, and biotechnology sectors. Importantly, emerging molecular docking studies highlight their ability to function as immune checkpoint modulators, opening novel opportunities in cancer immunotherapy. Key findings highlight β-glucans as versatile, sustainable agents that bridge nutrition, medicine, and industry. The uniqueness of this work lies in its holistic synthesis of structure–function relationships and translational relevance, positioning β-glucans as pivotal 21st -century biomolecules for advancing drug delivery and global innovation.