Nanomedicine for Benign Prostatic Hyperplasia: Pathological Axes and Translational Evidence

Benign prostatic hyperplasia (BPH) is heterogeneous, and lower urinary tract symptoms also depend on smooth-muscle tone, outlet mechanics and bladder function. Nanomedicine research spans formulation development, animal experiments and limited clinical exploration, but these stages do not establish a continuous chain from delivery to durable patient benefit. This critical narrative review combines a structured PubMed update search through September 7, 2026 with descriptive evidence mapping. Historical search strings were unavailable; the update queries and records are retained, and retrieved records are distinguished from the curated study inventory. We organize relevant biology into inflammatory, hormonal-metabolic and fibrotic/extracellular-matrix axes and propose a barrier-signal-payload-feedback framework. The evidence tiers and decision gates are proposed analytical tools, not validated clinical classifications or regulatory pathways. Source-checked reports predominantly assess formulation properties, systemic exposure, organ size, histology or molecular outcomes. Healthy-volunteer pharmacokinetics does not constitute BPH therapeutic evidence, and whole-prostate exposure does not establish delivery to nodules or specific cells. A small nanomicellar-curcumin trial provides an early symptom signal below its study-defined clinical-importance threshold. Animal saline-loaded urine measurements and short-term cystometry from an adjacent local hydrogel represent different functional outcomes and cannot be equated with durable clinical benefit. The three-axis framework also does not establish which process initiates early nodular formation. Progress requires reproducible disease-state stratification, quantitative lesion delivery with prespecified target engagement, and sustained functional benefit supported by chronic safety and manufacturability. Added formulation complexity is justified only by measurable incremental value over simpler formulations, free payloads or appropriate standard treatment.