Understanding the Sports Underwear ecosystem requires mapping the flow from upstream inputs through midstream transformation to downstream delivery. Raw material and component suppliers furnish high‑performance fibers, elastane blends, and functional finishes that define product attributes. Textile mills and OEM manufacturers act as the midstream core, converting those inputs into finished garments while integrating sensor or antimicrobial technologies supplied by specialist technology firms. System integrators align design, sourcing, and production schedules for both private‑label and global brands. Downstream, distributors, e‑commerce platforms, and specialty retailers convey the final products to end users, who evaluate items based on fit, moisture management, and durability. Sustainability considerations, such as recycled polyester content and low‑impact dyeing, are increasingly embedded in sourcing decisions. Value is captured at each transition through margin generation, brand differentiation, and data feedback that informs subsequent design cycles.