Biologic Injection Therapy for Shoulder Disorders: A Narrative Review Comparing Platelet-Rich Plasma and Bone Marrow Aspirate Concentrate

Background and Objectives: Shoulder disorders—including rotator cuff disease, glenohumeral osteoarthritis (GH OA), and adhesive capsulitis—are among the most prevalent musculoskeletal conditions and are frequently refractory to conservative management. Platelet-rich plasma (PRP) and bone marrow aspirate concentrate (BMAC) have attracted increasing clinical interest as regenerative alternatives to corticosteroid injection, but a comparative appraisal of these two principal biologics across the full spectrum of shoulder pathology is lacking. Materials and Methods: This narrative review is based on structured searches of MEDLINE, Embase, Cochrane CENTRAL, and Scopus for clinical studies (randomized controlled trials [RCTs], comparative studies, and prospective series) and evidence syntheses evaluating PRP or BMAC in shoulder disorders. Studies were synthesized narratively by biologic type and disorder; no formal systematic-review or scoping-review reporting protocol was applied. Current society guidelines and consensus statements were additionally examined to position each biologic, and PRP formulation subgroups (leukocyte-rich versus leukocyte-poor) were considered. Results: PRP has the larger shoulder-specific evidence base, supported by several RCTs and meta-analyses in rotator cuff tendinopathy and in adhesive capsulitis; however, results are heterogeneous, effect sizes are generally modest, and some trials show no advantage over saline or corticosteroid. BMAC shoulder evidence is sparse and is strongest as a biological augment to rotator cuff repair (supported chiefly by a case-controlled study) rather than as a standalone injection; standalone shoulder BMAC RCTs are essentially absent. No published RCT directly compares PRP with BMAC for a shoulder disorder; the only direct randomized head-to-head comparison available is in knee osteoarthritis, where the two were reported to be equivalent at two years. Where PRP formulation was examined, leukocyte-poor preparations were associated with better structural and pain outcomes and leukocyte-rich preparations with functional gains in the surgical setting; current society guidance (e.g., the 2025 American Academy of Orthopaedic Surgeons [AAOS] rotator cuff guideline) does not endorse routine PRP use, and BMAC is not yet incorporated into shoulder guideline recommendations. Conclusions: PRP rests on a larger but still heterogeneous evidence base for shoulder disorders, whereas BMAC is biologically promising but clinically under-evidenced in the shoulder. Neither biologic is established as superior. Standardized, shoulder-specific head-to-head RCTs—incorporating biologic characterization, structural (imaging) outcomes, and longer follow-up—represent the most important research priority in this field.